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school-of-sre/level102/system_troubleshooting_and_performance/troubleshooting-example/index.html
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Level 101
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<li class="md-nav__item md-nav__item--nested">
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Fundamentals Series
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<span class="md-nav__icon md-icon"></span>
Fundamentals Series
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<ul class="md-nav__list" data-md-scrollfix>
<!-- Nested navigation item -->
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<!-- Navigation item with nested items -->
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<!-- Navigation pruning -->
<!-- Nested navigation item -->
<li class="md-nav__item md-nav__item--nested">
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<!-- Active checkbox expands items contained within nested section -->
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type="checkbox"
id="__nav_2_1_1"
/>
<!-- Toggle to expand nested items -->
<label
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<span class="md-ellipsis">
Linux Basics
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<label class="md-nav__title" for="__nav_2_1_1">
<span class="md-nav__icon md-icon"></span>
Linux Basics
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<ul class="md-nav__list" data-md-scrollfix>
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Introduction
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Command Line Basics
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Server Administration
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<!-- Navigation item with nested items -->
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<!-- Navigation link title -->
<span class="md-ellipsis">
Conclusion
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</li>
<!-- Currently active page -->
<!-- Determine classes -->
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<!-- Navigation item with nested items -->
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<!-- Nested navigation item -->
<li class="md-nav__item md-nav__item--nested">
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id="__nav_2_1_2"
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<!-- Toggle to expand nested items -->
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tabindex="0"
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<span class="md-ellipsis">
Git
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<!-- Nested navigation -->
<nav
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data-md-level="3"
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<label class="md-nav__title" for="__nav_2_1_2">
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Git
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<ul class="md-nav__list" data-md-scrollfix>
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<li class="md-nav__item">
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<!-- Navigation link title -->
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Git Basics
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<li class="md-nav__item">
<a href="../../../level101/git/branches/" class="md-nav__link">
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<!-- Navigation link title -->
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Working With Branches
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<a href="../../../level101/git/github-hooks/" class="md-nav__link">
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<!-- Navigation link title -->
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Github and Hooks
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<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/git/conclusion/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Conclusion
</span>
<!-- Navigation link status -->
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</li>
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</nav>
<!-- Pruned navigation item -->
</li>
<!-- Currently active page -->
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<!-- Determine all nested items that are index pages -->
<!-- Navigation tabs -->
<!-- Render 1st level items with nested items as sections -->
<!-- Navigation pruning -->
<!-- Nested navigation item -->
<li class="md-nav__item md-nav__item--nested">
<!-- Determine checked and indeterminate state -->
<!-- Active checkbox expands items contained within nested section -->
<input
class="md-nav__toggle md-toggle "
type="checkbox"
id="__nav_2_1_3"
/>
<!-- Toggle to expand nested items -->
<label
class="md-nav__link"
for="__nav_2_1_3"
id="__nav_2_1_3_label"
tabindex="0"
>
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Linux Networking
</span>
<!-- Navigation link status -->
<span class="md-nav__icon md-icon"></span>
</label>
<!-- Toggle to expand nested items with link to index page -->
<!-- Nested navigation -->
<nav
class="md-nav"
data-md-level="3"
aria-labelledby="__nav_2_1_3_label"
aria-expanded="false"
>
<label class="md-nav__title" for="__nav_2_1_3">
<span class="md-nav__icon md-icon"></span>
Linux Networking
</label>
<ul class="md-nav__list" data-md-scrollfix>
<!-- Nested navigation item -->
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/linux_networking/intro/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Introduction
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/linux_networking/dns/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
DNS
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/linux_networking/udp/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
UDP
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/linux_networking/http/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
HTTP
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/linux_networking/tcp/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
TCP
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/linux_networking/ipr/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Routing
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/linux_networking/conclusion/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Conclusion
</span>
<!-- Navigation link status -->
</a>
</li>
</ul>
</nav>
<!-- Pruned navigation item -->
</li>
<!-- Currently active page -->
</ul>
</nav>
<!-- Pruned navigation item -->
</li>
<!-- Currently active page -->
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<!-- Determine all nested items that are index pages -->
<!-- Navigation tabs -->
<!-- Render 1st level items with nested items as sections -->
<!-- Navigation pruning -->
<!-- Nested navigation item -->
<li class="md-nav__item md-nav__item--nested">
<!-- Determine checked and indeterminate state -->
<!-- Active checkbox expands items contained within nested section -->
<input
class="md-nav__toggle md-toggle "
type="checkbox"
id="__nav_2_2"
/>
<!-- Toggle to expand nested items -->
<label
class="md-nav__link"
for="__nav_2_2"
id="__nav_2_2_label"
tabindex="0"
>
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Python and Web
</span>
<!-- Navigation link status -->
<span class="md-nav__icon md-icon"></span>
</label>
<!-- Toggle to expand nested items with link to index page -->
<!-- Nested navigation -->
<nav
class="md-nav"
data-md-level="2"
aria-labelledby="__nav_2_2_label"
aria-expanded="false"
>
<label class="md-nav__title" for="__nav_2_2">
<span class="md-nav__icon md-icon"></span>
Python and Web
</label>
<ul class="md-nav__list" data-md-scrollfix>
<!-- Nested navigation item -->
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/python_web/intro/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Introduction
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/python_web/python-concepts/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Some Python Concepts
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/python_web/python-web-flask/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Python, Web and Flask
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/python_web/url-shorten-app/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
The URL Shortening App
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/python_web/sre-conclusion/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Conclusion
</span>
<!-- Navigation link status -->
</a>
</li>
</ul>
</nav>
<!-- Pruned navigation item -->
</li>
<!-- Currently active page -->
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<!-- Determine all nested items that are index pages -->
<!-- Navigation tabs -->
<!-- Render 1st level items with nested items as sections -->
<!-- Navigation pruning -->
<!-- Nested navigation item -->
<li class="md-nav__item md-nav__item--nested">
<!-- Determine checked and indeterminate state -->
<!-- Active checkbox expands items contained within nested section -->
<input
class="md-nav__toggle md-toggle "
type="checkbox"
id="__nav_2_3"
/>
<!-- Toggle to expand nested items -->
<label
class="md-nav__link"
for="__nav_2_3"
id="__nav_2_3_label"
tabindex="0"
>
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Data
</span>
<!-- Navigation link status -->
<span class="md-nav__icon md-icon"></span>
</label>
<!-- Toggle to expand nested items with link to index page -->
<!-- Nested navigation -->
<nav
class="md-nav"
data-md-level="2"
aria-labelledby="__nav_2_3_label"
aria-expanded="false"
>
<label class="md-nav__title" for="__nav_2_3">
<span class="md-nav__icon md-icon"></span>
Data
</label>
<ul class="md-nav__list" data-md-scrollfix>
<!-- Nested navigation item -->
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<!-- Determine all nested items that are index pages -->
<!-- Navigation tabs -->
<!-- Render 1st level items with nested items as sections -->
<!-- Navigation pruning -->
<!-- Nested navigation item -->
<li class="md-nav__item md-nav__item--nested">
<!-- Determine checked and indeterminate state -->
<!-- Active checkbox expands items contained within nested section -->
<input
class="md-nav__toggle md-toggle "
type="checkbox"
id="__nav_2_3_1"
/>
<!-- Toggle to expand nested items -->
<label
class="md-nav__link"
for="__nav_2_3_1"
id="__nav_2_3_1_label"
tabindex="0"
>
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Relational Databases
</span>
<!-- Navigation link status -->
<span class="md-nav__icon md-icon"></span>
</label>
<!-- Toggle to expand nested items with link to index page -->
<!-- Nested navigation -->
<nav
class="md-nav"
data-md-level="3"
aria-labelledby="__nav_2_3_1_label"
aria-expanded="false"
>
<label class="md-nav__title" for="__nav_2_3_1">
<span class="md-nav__icon md-icon"></span>
Relational Databases
</label>
<ul class="md-nav__list" data-md-scrollfix>
<!-- Nested navigation item -->
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/databases_sql/intro/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Introduction
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/databases_sql/concepts/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Key Concepts
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/databases_sql/mysql/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
MySQL
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/databases_sql/innodb/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
InnoDB
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/databases_sql/backup_recovery/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Backup and Recovery
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/databases_sql/replication/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
MySQL Replication
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/databases_sql/operations/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Operational Concepts
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/databases_sql/select_query/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Select Query
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/databases_sql/query_performance/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Query Performance
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/databases_sql/lab/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Lab
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/databases_sql/conclusion/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Conclusion
</span>
<!-- Navigation link status -->
</a>
</li>
</ul>
</nav>
<!-- Pruned navigation item -->
</li>
<!-- Currently active page -->
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<!-- Determine all nested items that are index pages -->
<!-- Navigation tabs -->
<!-- Render 1st level items with nested items as sections -->
<!-- Navigation pruning -->
<!-- Nested navigation item -->
<li class="md-nav__item md-nav__item--nested">
<!-- Determine checked and indeterminate state -->
<!-- Active checkbox expands items contained within nested section -->
<input
class="md-nav__toggle md-toggle "
type="checkbox"
id="__nav_2_3_2"
/>
<!-- Toggle to expand nested items -->
<label
class="md-nav__link"
for="__nav_2_3_2"
id="__nav_2_3_2_label"
tabindex="0"
>
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
NoSQL
</span>
<!-- Navigation link status -->
<span class="md-nav__icon md-icon"></span>
</label>
<!-- Toggle to expand nested items with link to index page -->
<!-- Nested navigation -->
<nav
class="md-nav"
data-md-level="3"
aria-labelledby="__nav_2_3_2_label"
aria-expanded="false"
>
<label class="md-nav__title" for="__nav_2_3_2">
<span class="md-nav__icon md-icon"></span>
NoSQL
</label>
<ul class="md-nav__list" data-md-scrollfix>
<!-- Nested navigation item -->
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/databases_nosql/intro/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Introduction
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/databases_nosql/key_concepts/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Key Concepts
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/databases_nosql/further_reading/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Conclusion
</span>
<!-- Navigation link status -->
</a>
</li>
</ul>
</nav>
<!-- Pruned navigation item -->
</li>
<!-- Currently active page -->
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<!-- Determine all nested items that are index pages -->
<!-- Navigation tabs -->
<!-- Render 1st level items with nested items as sections -->
<!-- Navigation pruning -->
<!-- Nested navigation item -->
<li class="md-nav__item md-nav__item--nested">
<!-- Determine checked and indeterminate state -->
<!-- Active checkbox expands items contained within nested section -->
<input
class="md-nav__toggle md-toggle "
type="checkbox"
id="__nav_2_3_3"
/>
<!-- Toggle to expand nested items -->
<label
class="md-nav__link"
for="__nav_2_3_3"
id="__nav_2_3_3_label"
tabindex="0"
>
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Message Queue
</span>
<!-- Navigation link status -->
<span class="md-nav__icon md-icon"></span>
</label>
<!-- Toggle to expand nested items with link to index page -->
<!-- Nested navigation -->
<nav
class="md-nav"
data-md-level="3"
aria-labelledby="__nav_2_3_3_label"
aria-expanded="false"
>
<label class="md-nav__title" for="__nav_2_3_3">
<span class="md-nav__icon md-icon"></span>
Message Queue
</label>
<ul class="md-nav__list" data-md-scrollfix>
<!-- Nested navigation item -->
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/messagequeue/intro/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Introduction
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/messagequeue/key_concepts/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Key Concepts
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/messagequeue/further_reading/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Conclusion
</span>
<!-- Navigation link status -->
</a>
</li>
</ul>
</nav>
<!-- Pruned navigation item -->
</li>
<!-- Currently active page -->
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<!-- Determine all nested items that are index pages -->
<!-- Navigation tabs -->
<!-- Render 1st level items with nested items as sections -->
<!-- Navigation pruning -->
<!-- Nested navigation item -->
<li class="md-nav__item md-nav__item--nested">
<!-- Determine checked and indeterminate state -->
<!-- Active checkbox expands items contained within nested section -->
<input
class="md-nav__toggle md-toggle "
type="checkbox"
id="__nav_2_3_4"
/>
<!-- Toggle to expand nested items -->
<label
class="md-nav__link"
for="__nav_2_3_4"
id="__nav_2_3_4_label"
tabindex="0"
>
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Big Data
</span>
<!-- Navigation link status -->
<span class="md-nav__icon md-icon"></span>
</label>
<!-- Toggle to expand nested items with link to index page -->
<!-- Nested navigation -->
<nav
class="md-nav"
data-md-level="3"
aria-labelledby="__nav_2_3_4_label"
aria-expanded="false"
>
<label class="md-nav__title" for="__nav_2_3_4">
<span class="md-nav__icon md-icon"></span>
Big Data
</label>
<ul class="md-nav__list" data-md-scrollfix>
<!-- Nested navigation item -->
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/big_data/intro/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Introduction
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/big_data/evolution/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Evolution and Architecture of Hadoop
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/big_data/tasks/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Conclusion
</span>
<!-- Navigation link status -->
</a>
</li>
</ul>
</nav>
<!-- Pruned navigation item -->
</li>
<!-- Currently active page -->
</ul>
</nav>
<!-- Pruned navigation item -->
</li>
<!-- Currently active page -->
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<!-- Determine all nested items that are index pages -->
<!-- Navigation tabs -->
<!-- Render 1st level items with nested items as sections -->
<!-- Navigation pruning -->
<!-- Nested navigation item -->
<li class="md-nav__item md-nav__item--nested">
<!-- Determine checked and indeterminate state -->
<!-- Active checkbox expands items contained within nested section -->
<input
class="md-nav__toggle md-toggle "
type="checkbox"
id="__nav_2_4"
/>
<!-- Toggle to expand nested items -->
<label
class="md-nav__link"
for="__nav_2_4"
id="__nav_2_4_label"
tabindex="0"
>
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Systems Design
</span>
<!-- Navigation link status -->
<span class="md-nav__icon md-icon"></span>
</label>
<!-- Toggle to expand nested items with link to index page -->
<!-- Nested navigation -->
<nav
class="md-nav"
data-md-level="2"
aria-labelledby="__nav_2_4_label"
aria-expanded="false"
>
<label class="md-nav__title" for="__nav_2_4">
<span class="md-nav__icon md-icon"></span>
Systems Design
</label>
<ul class="md-nav__list" data-md-scrollfix>
<!-- Nested navigation item -->
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/systems_design/intro/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Introduction
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/systems_design/scalability/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Scalability
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/systems_design/availability/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Availability
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/systems_design/fault-tolerance/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Fault Tolerance
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/systems_design/conclusion/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Conclusion
</span>
<!-- Navigation link status -->
</a>
</li>
</ul>
</nav>
<!-- Pruned navigation item -->
</li>
<!-- Currently active page -->
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<!-- Determine all nested items that are index pages -->
<!-- Navigation tabs -->
<!-- Render 1st level items with nested items as sections -->
<!-- Navigation pruning -->
<!-- Nested navigation item -->
<li class="md-nav__item md-nav__item--nested">
<!-- Determine checked and indeterminate state -->
<!-- Active checkbox expands items contained within nested section -->
<input
class="md-nav__toggle md-toggle "
type="checkbox"
id="__nav_2_5"
/>
<!-- Toggle to expand nested items -->
<label
class="md-nav__link"
for="__nav_2_5"
id="__nav_2_5_label"
tabindex="0"
>
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Metrics and Monitoring
</span>
<!-- Navigation link status -->
<span class="md-nav__icon md-icon"></span>
</label>
<!-- Toggle to expand nested items with link to index page -->
<!-- Nested navigation -->
<nav
class="md-nav"
data-md-level="2"
aria-labelledby="__nav_2_5_label"
aria-expanded="false"
>
<label class="md-nav__title" for="__nav_2_5">
<span class="md-nav__icon md-icon"></span>
Metrics and Monitoring
</label>
<ul class="md-nav__list" data-md-scrollfix>
<!-- Nested navigation item -->
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/metrics_and_monitoring/introduction/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Introduction
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/metrics_and_monitoring/command-line_tools/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Command-line Tools
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/metrics_and_monitoring/third-party_monitoring/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Third-party Monitoring
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/metrics_and_monitoring/alerts/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Proactive Monitoring with Alerts
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/metrics_and_monitoring/best_practices/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Best Practices for Monitoring
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/metrics_and_monitoring/observability/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Observability
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/metrics_and_monitoring/conclusion/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Conclusion
</span>
<!-- Navigation link status -->
</a>
</li>
</ul>
</nav>
<!-- Pruned navigation item -->
</li>
<!-- Currently active page -->
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<!-- Determine all nested items that are index pages -->
<!-- Navigation tabs -->
<!-- Render 1st level items with nested items as sections -->
<!-- Navigation pruning -->
<!-- Nested navigation item -->
<li class="md-nav__item md-nav__item--nested">
<!-- Determine checked and indeterminate state -->
<!-- Active checkbox expands items contained within nested section -->
<input
class="md-nav__toggle md-toggle "
type="checkbox"
id="__nav_2_6"
/>
<!-- Toggle to expand nested items -->
<label
class="md-nav__link"
for="__nav_2_6"
id="__nav_2_6_label"
tabindex="0"
>
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Security
</span>
<!-- Navigation link status -->
<span class="md-nav__icon md-icon"></span>
</label>
<!-- Toggle to expand nested items with link to index page -->
<!-- Nested navigation -->
<nav
class="md-nav"
data-md-level="2"
aria-labelledby="__nav_2_6_label"
aria-expanded="false"
>
<label class="md-nav__title" for="__nav_2_6">
<span class="md-nav__icon md-icon"></span>
Security
</label>
<ul class="md-nav__list" data-md-scrollfix>
<!-- Nested navigation item -->
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/security/intro/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Introduction
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/security/fundamentals/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Fundamentals of Security
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/security/network_security/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Network Security
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/security/threats_attacks_defences/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Threat, Attacks & Defences
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/security/writing_secure_code/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Writing Secure code
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../../level101/security/conclusion/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Conclusion
</span>
<!-- Navigation link status -->
</a>
</li>
</ul>
</nav>
<!-- Pruned navigation item -->
</li>
<!-- Currently active page -->
</ul>
</nav>
<!-- Pruned navigation item -->
</li>
<!-- Currently active page -->
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<!-- Determine all nested items that are index pages -->
<!-- Navigation tabs -->
<!-- Render 1st level items with nested items as sections -->
<!-- Navigation pruning -->
<!-- Nested navigation item -->
<li class="md-nav__item md-nav__item--active md-nav__item--section md-nav__item--nested">
<!-- Determine checked and indeterminate state -->
<!-- Active checkbox expands items contained within nested section -->
<input
class="md-nav__toggle md-toggle "
type="checkbox"
id="__nav_3"
checked
/>
<!-- Toggle to expand nested items -->
<label
class="md-nav__link"
for="__nav_3"
id="__nav_3_label"
tabindex=""
>
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Level 102
</span>
<!-- Navigation link status -->
<span class="md-nav__icon md-icon"></span>
</label>
<!-- Toggle to expand nested items with link to index page -->
<!-- Nested navigation -->
<nav
class="md-nav"
data-md-level="1"
aria-labelledby="__nav_3_label"
aria-expanded="true"
>
<label class="md-nav__title" for="__nav_3">
<span class="md-nav__icon md-icon"></span>
Level 102
</label>
<ul class="md-nav__list" data-md-scrollfix>
<!-- Nested navigation item -->
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<!-- Determine all nested items that are index pages -->
<!-- Navigation tabs -->
<!-- Render 1st level items with nested items as sections -->
<!-- Navigation pruning -->
<!-- Nested navigation item -->
<li class="md-nav__item md-nav__item--nested">
<!-- Determine checked and indeterminate state -->
<!-- Active checkbox expands items contained within nested section -->
<input
class="md-nav__toggle md-toggle "
type="checkbox"
id="__nav_3_1"
/>
<!-- Toggle to expand nested items -->
<label
class="md-nav__link"
for="__nav_3_1"
id="__nav_3_1_label"
tabindex="0"
>
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Linux Intermediate
</span>
<!-- Navigation link status -->
<span class="md-nav__icon md-icon"></span>
</label>
<!-- Toggle to expand nested items with link to index page -->
<!-- Nested navigation -->
<nav
class="md-nav"
data-md-level="2"
aria-labelledby="__nav_3_1_label"
aria-expanded="false"
>
<label class="md-nav__title" for="__nav_3_1">
<span class="md-nav__icon md-icon"></span>
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<ul class="md-nav__list" data-md-scrollfix>
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<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../linux_intermediate/introduction/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Introduction
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<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../linux_intermediate/package_management/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Package Management
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<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../linux_intermediate/storage_media/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Storage Media
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<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../linux_intermediate/archiving_backup/" class="md-nav__link">
<!-- Navigation link icon -->
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<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../linux_intermediate/introvim/" class="md-nav__link">
<!-- Navigation link icon -->
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<span class="md-ellipsis">
Introduction to Vim
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<li class="md-nav__item">
<a href="../../linux_intermediate/bashscripting/" class="md-nav__link">
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Bash Scripting
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<li class="md-nav__item">
<a href="../../linux_intermediate/conclusion/" class="md-nav__link">
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<!-- Currently active page -->
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<!-- Navigation tabs -->
<!-- Render 1st level items with nested items as sections -->
<!-- Navigation pruning -->
<!-- Nested navigation item -->
<li class="md-nav__item md-nav__item--nested">
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<!-- Active checkbox expands items contained within nested section -->
<input
class="md-nav__toggle md-toggle "
type="checkbox"
id="__nav_3_2"
/>
<!-- Toggle to expand nested items -->
<label
class="md-nav__link"
for="__nav_3_2"
id="__nav_3_2_label"
tabindex="0"
>
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<!-- Navigation link title -->
<span class="md-ellipsis">
Linux Advanced
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<span class="md-nav__icon md-icon"></span>
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<!-- Nested navigation -->
<nav
class="md-nav"
data-md-level="2"
aria-labelledby="__nav_3_2_label"
aria-expanded="false"
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<label class="md-nav__title" for="__nav_3_2">
<span class="md-nav__icon md-icon"></span>
Linux Advanced
</label>
<ul class="md-nav__list" data-md-scrollfix>
<!-- Nested navigation item -->
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<!-- Navigation tabs -->
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<!-- Navigation pruning -->
<!-- Nested navigation item -->
<li class="md-nav__item md-nav__item--nested">
<!-- Determine checked and indeterminate state -->
<!-- Active checkbox expands items contained within nested section -->
<input
class="md-nav__toggle md-toggle "
type="checkbox"
id="__nav_3_2_1"
/>
<!-- Toggle to expand nested items -->
<label
class="md-nav__link"
for="__nav_3_2_1"
id="__nav_3_2_1_label"
tabindex="0"
>
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Containerization And Orchestration
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<span class="md-nav__icon md-icon"></span>
</label>
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<!-- Nested navigation -->
<nav
class="md-nav"
data-md-level="3"
aria-labelledby="__nav_3_2_1_label"
aria-expanded="false"
>
<label class="md-nav__title" for="__nav_3_2_1">
<span class="md-nav__icon md-icon"></span>
Containerization And Orchestration
</label>
<ul class="md-nav__list" data-md-scrollfix>
<!-- Nested navigation item -->
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<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../containerization_and_orchestration/intro/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Introduction
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</a>
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<!-- Determine classes -->
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<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../containerization_and_orchestration/intro_to_containers/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Introduction To Containers
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</a>
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<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../containerization_and_orchestration/containerization_with_docker/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Containerization With Docker
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<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../containerization_and_orchestration/orchestration_with_kubernetes/" class="md-nav__link">
<!-- Navigation link icon -->
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<span class="md-ellipsis">
Orchestration With Kubernetes
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<!-- Navigation link status -->
</a>
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<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../containerization_and_orchestration/conclusion/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Conclusion
</span>
<!-- Navigation link status -->
</a>
</li>
</ul>
</nav>
<!-- Pruned navigation item -->
</li>
<!-- Currently active page -->
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<!-- Determine all nested items that are index pages -->
<!-- Navigation tabs -->
<!-- Render 1st level items with nested items as sections -->
<!-- Navigation pruning -->
<!-- Nested navigation item -->
<li class="md-nav__item md-nav__item--nested">
<!-- Determine checked and indeterminate state -->
<!-- Active checkbox expands items contained within nested section -->
<input
class="md-nav__toggle md-toggle "
type="checkbox"
id="__nav_3_2_2"
/>
<!-- Toggle to expand nested items -->
<label
class="md-nav__link"
for="__nav_3_2_2"
id="__nav_3_2_2_label"
tabindex="0"
>
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
System Calls and Signals
</span>
<!-- Navigation link status -->
<span class="md-nav__icon md-icon"></span>
</label>
<!-- Toggle to expand nested items with link to index page -->
<!-- Nested navigation -->
<nav
class="md-nav"
data-md-level="3"
aria-labelledby="__nav_3_2_2_label"
aria-expanded="false"
>
<label class="md-nav__title" for="__nav_3_2_2">
<span class="md-nav__icon md-icon"></span>
System Calls and Signals
</label>
<ul class="md-nav__list" data-md-scrollfix>
<!-- Nested navigation item -->
<!-- Determine classes -->
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<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../system_calls_and_signals/intro/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Introduction
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
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<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../system_calls_and_signals/signals/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Signals
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../system_calls_and_signals/system_calls/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
System Calls
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
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<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../system_calls_and_signals/conclusion/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Conclusion
</span>
<!-- Navigation link status -->
</a>
</li>
</ul>
</nav>
<!-- Pruned navigation item -->
</li>
<!-- Currently active page -->
</ul>
</nav>
<!-- Pruned navigation item -->
</li>
<!-- Currently active page -->
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<!-- Determine all nested items that are index pages -->
<!-- Navigation tabs -->
<!-- Render 1st level items with nested items as sections -->
<!-- Navigation pruning -->
<!-- Nested navigation item -->
<li class="md-nav__item md-nav__item--nested">
<!-- Determine checked and indeterminate state -->
<!-- Active checkbox expands items contained within nested section -->
<input
class="md-nav__toggle md-toggle "
type="checkbox"
id="__nav_3_3"
/>
<!-- Toggle to expand nested items -->
<label
class="md-nav__link"
for="__nav_3_3"
id="__nav_3_3_label"
tabindex="0"
>
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Networking
</span>
<!-- Navigation link status -->
<span class="md-nav__icon md-icon"></span>
</label>
<!-- Toggle to expand nested items with link to index page -->
<!-- Nested navigation -->
<nav
class="md-nav"
data-md-level="2"
aria-labelledby="__nav_3_3_label"
aria-expanded="false"
>
<label class="md-nav__title" for="__nav_3_3">
<span class="md-nav__icon md-icon"></span>
Networking
</label>
<ul class="md-nav__list" data-md-scrollfix>
<!-- Nested navigation item -->
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<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../networking/introduction/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Introduction
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
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<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../networking/security/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Security
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<!-- Navigation link status -->
</a>
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<!-- Determine classes -->
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<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../networking/scale/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Scale
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<!-- Navigation link status -->
</a>
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<!-- Determine classes -->
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<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../networking/rtt/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
RTT
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<!-- Navigation link status -->
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<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../networking/infrastructure-features/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Infrastructure Services
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<!-- Navigation link status -->
</a>
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<!-- Determine classes -->
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<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../networking/conclusion/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Conclusion
</span>
<!-- Navigation link status -->
</a>
</li>
</ul>
</nav>
<!-- Pruned navigation item -->
</li>
<!-- Currently active page -->
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<!-- Determine all nested items that are index pages -->
<!-- Navigation tabs -->
<!-- Render 1st level items with nested items as sections -->
<!-- Navigation pruning -->
<!-- Nested navigation item -->
<li class="md-nav__item md-nav__item--nested">
<!-- Determine checked and indeterminate state -->
<!-- Active checkbox expands items contained within nested section -->
<input
class="md-nav__toggle md-toggle "
type="checkbox"
id="__nav_3_4"
/>
<!-- Toggle to expand nested items -->
<label
class="md-nav__link"
for="__nav_3_4"
id="__nav_3_4_label"
tabindex="0"
>
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
System Design
</span>
<!-- Navigation link status -->
<span class="md-nav__icon md-icon"></span>
</label>
<!-- Toggle to expand nested items with link to index page -->
<!-- Nested navigation -->
<nav
class="md-nav"
data-md-level="2"
aria-labelledby="__nav_3_4_label"
aria-expanded="false"
>
<label class="md-nav__title" for="__nav_3_4">
<span class="md-nav__icon md-icon"></span>
System Design
</label>
<ul class="md-nav__list" data-md-scrollfix>
<!-- Nested navigation item -->
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../system_design/intro/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Introduction
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
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<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../system_design/large-system-design/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Large System Design
</span>
<!-- Navigation link status -->
</a>
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<!-- Determine classes -->
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<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../system_design/scaling/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Scaling
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../system_design/scaling-beyond-the-datacenter/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Scaling Beyond the Data Center
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<!-- Navigation link status -->
</a>
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<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../system_design/resiliency/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Resiliency
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
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<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../system_design/conclusion/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Conclusion
</span>
<!-- Navigation link status -->
</a>
</li>
</ul>
</nav>
<!-- Pruned navigation item -->
</li>
<!-- Currently active page -->
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<!-- Determine all nested items that are index pages -->
<!-- Navigation tabs -->
<!-- Render 1st level items with nested items as sections -->
<!-- Navigation pruning -->
<!-- Nested navigation item -->
<li class="md-nav__item md-nav__item--active md-nav__item--nested">
<!-- Determine checked and indeterminate state -->
<!-- Active checkbox expands items contained within nested section -->
<input
class="md-nav__toggle md-toggle "
type="checkbox"
id="__nav_3_5"
checked
/>
<!-- Toggle to expand nested items -->
<label
class="md-nav__link"
for="__nav_3_5"
id="__nav_3_5_label"
tabindex="0"
>
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
System Troubleshooting and Performance Improvements
</span>
<!-- Navigation link status -->
<span class="md-nav__icon md-icon"></span>
</label>
<!-- Toggle to expand nested items with link to index page -->
<!-- Nested navigation -->
<nav
class="md-nav"
data-md-level="2"
aria-labelledby="__nav_3_5_label"
aria-expanded="true"
>
<label class="md-nav__title" for="__nav_3_5">
<span class="md-nav__icon md-icon"></span>
System Troubleshooting and Performance Improvements
</label>
<ul class="md-nav__list" data-md-scrollfix>
<!-- Nested navigation item -->
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../introduction/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Introduction
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../troubleshooting/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Troubleshooting
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
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<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../important-tools/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Important Tools
</span>
<!-- Navigation link status -->
</a>
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<!-- Determine classes -->
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<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../performance-improvements/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Performance Improvements
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item md-nav__item--active">
<!-- State toggle -->
<input
class="md-nav__toggle md-toggle"
type="checkbox"
id="__toc"
/>
<!-- Hack: see partials/toc.html for more information -->
<!-- Navigation link to table of contents -->
<label class="md-nav__link md-nav__link--active" for="__toc">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Troubleshooting Example
</span>
<!-- Navigation link status -->
<span class="md-nav__icon md-icon"></span>
</label>
<a
href="./"
class="md-nav__link md-nav__link--active"
>
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Troubleshooting Example
</span>
<!-- Navigation link status -->
</a>
<!-- Table of contents -->
<nav class="md-nav md-nav--secondary" aria-label="Table of contents">
<label class="md-nav__title" for="__toc">
<span class="md-nav__icon md-icon"></span>
Table of contents
</label>
<ul class="md-nav__list" data-md-component="toc" data-md-scrollfix>
<li class="md-nav__item">
<a href="#example-memory-leak" class="md-nav__link">
<span class="md-ellipsis">
Example - Memory leak :
</span>
</a>
</li>
</ul>
</nav>
</li>
<!-- Navigation item -->
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../conclusion/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Conclusion
</span>
<!-- Navigation link status -->
</a>
</li>
</ul>
</nav>
<!-- Pruned navigation item -->
</li>
<!-- Currently active page -->
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<!-- Determine all nested items that are index pages -->
<!-- Navigation tabs -->
<!-- Render 1st level items with nested items as sections -->
<!-- Navigation pruning -->
<!-- Nested navigation item -->
<li class="md-nav__item md-nav__item--nested">
<!-- Determine checked and indeterminate state -->
<!-- Active checkbox expands items contained within nested section -->
<input
class="md-nav__toggle md-toggle "
type="checkbox"
id="__nav_3_6"
/>
<!-- Toggle to expand nested items -->
<label
class="md-nav__link"
for="__nav_3_6"
id="__nav_3_6_label"
tabindex="0"
>
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Continuous Integration and Continuous Delivery
</span>
<!-- Navigation link status -->
<span class="md-nav__icon md-icon"></span>
</label>
<!-- Toggle to expand nested items with link to index page -->
<!-- Nested navigation -->
<nav
class="md-nav"
data-md-level="2"
aria-labelledby="__nav_3_6_label"
aria-expanded="false"
>
<label class="md-nav__title" for="__nav_3_6">
<span class="md-nav__icon md-icon"></span>
Continuous Integration and Continuous Delivery
</label>
<ul class="md-nav__list" data-md-scrollfix>
<!-- Nested navigation item -->
<!-- Determine classes -->
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<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../continuous_integration_and_continuous_delivery/introduction/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Introduction
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../continuous_integration_and_continuous_delivery/introduction_to_cicd/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
What is CI/CD?
</span>
<!-- Navigation link status -->
</a>
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<!-- Determine classes -->
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<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../continuous_integration_and_continuous_delivery/cicd_brief_history/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Brief History
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../continuous_integration_and_continuous_delivery/continuous_integration_build_pipeline/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Continuous Integration
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
<!-- Navigation item with nested items -->
<li class="md-nav__item">
<a href="../../continuous_integration_and_continuous_delivery/continuous_delivery_release_pipeline/" class="md-nav__link">
<!-- Navigation link icon -->
<!-- Navigation link title -->
<span class="md-ellipsis">
Continuous Delivery and Deployment
</span>
<!-- Navigation link status -->
</a>
</li>
<!-- Determine classes -->
<!-- Determine active page for paginated views -->
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Example - Memory leak :
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<h1>Troubleshooting Example</h1>
<p>In this section we will see an example of an issue and try to troubleshoot it, and at the end a few famous troubleshooting stories are shared, which were shared by LinkedIn engineers earlier.</p>
<h3 id="example-memory-leak">Example - Memory leak :</h3>
<p>Often memory leak issues go unnoticed until the service becomes unresponsive after running for some time (days, week or even month) until service is restarted or bug is fixed, In such cases, service memory usage will reflect in increasing order in the metric graph, something like this graph.</p>
<p><img alt="" src="../images/MemUsageChart.png" /></p>
<p>Memory leak is mismanagement of memory allocations by application, where unneeded memory is not released, over the period of time objects continue to pile up in memory resulting in service crash. Generally such non-released objects get sorted by <a href="https://en.wikipedia.org/wiki/Garbage_collection_(computer_science)">garbage collector</a> automatically, but sometimes due to a bug it fails. Debugging helps in figuring where much of the application storage memory is being applied. Then, you start tracking and filter everything based on usage. In case, you find objects that arent in use, but are referenced, you can get rid of them by deleting them to avoid memory leaks. In the case of python applications, it comes with inbuilt features like <a href="https://docs.python.org/3/library/tracemalloc.html">tracemalloc</a>. This module can help pinpoint where an object was allocated first. Almost every language comes with a set of tools/libraries (inbuilt or external) which helps find memory issues. Similarly for Java there is a famous memory leak detection tool called <a href="http://visualvm.java.net/intro.html">Java VisualVM</a>.</p>
<p>Lets see how a dummy flask based web app with a memory leak bug, with every request its memory usage keeps increasing, and how we can use tracemalloc to capture the leak.</p>
<p>Assumption -: A python virtual environment is created, and flask is installed in it.</p>
<p><strong>A bare minimum flask code with bug, read comments for more info</strong>
<img alt="" src="../images/FlaskCode.png" /></p>
<p><strong>Starting flask app</strong>
<img alt="" src="../images/FlaskStart.png" /></p>
<p><strong>On start, Its memory usage is around 26576 kb, i.e approx 26MB</strong>
<img alt="" src="../images/MemUsage01.png" /></p>
<p><strong>Now with every subsequent GET request, We can notice that process memory usage continues to increase slowly.</strong>
<img alt="" src="../images/MemUsage02.png" /></p>
<p><strong>Now lets try 10000 requests, to see if memory usage increases heavily.</strong>
To hit a high number of requests, we use an Apache benchmarking tool called <a href="https://httpd.apache.org/docs/2.4/programs/ab.html">“ab”</a>. After 10000 hits, we can notice memory usage of flask app is jumped almost 15 times, i.e from initial <strong>26576 KB to 419316 KB, i.e from roughly 26 MB to 419 MB</strong>, Thats a huge jump for such a small webapp.
<img alt="" src="../images/MemUsage03.png" /></p>
<p><strong>Lets try the python <a href="https://docs.python.org/3/library/tracemalloc.html">tracemalloc</a> module to try to understand the application memory allocations.</strong> Tracemalloc takes memory snapshots at a particular point, performing various statistics on the same. </p>
<p>Adding a bare minimum code to our app.py file, no change in fetchuserdata.py file, it will allow us to capture tracemalloc snapshots whenever we will hit /capture uri.
<img alt="" src="../images/Tracemalloc01.png" /></p>
<p><strong>After restart of app.py (flask run)</strong>, we will
- First hit http://127.0.0.1:5000/capture
- Then hit http://127.0.0.1:5000/ 10000 times, for memory leak/s to take place.
- Finally hit http://127.0.0.1:5000/capture again to take a snapshot to know which line has the most allocation.
<img alt="" src="../images/Tracemalloc02.png" /></p>
<p>In the final snapshot, we noticed the exact module and lineno where most allocation happened. I.e fetchuserdata.py, line no 6, after 10000 hits, it is holding 419 MB of memory.
<img alt="" src="../images/Tracemalloc03.png" /></p>
<p><strong>Summary</strong></p>
<p>Above example shows how a bug can lead to memory leak, and how we can use <a href="https://docs.python.org/3/library/tracemalloc.html">tracemalloc</a> to understand where it is. In real world applications are way more complex than the above dummy example, you must understand that using tracemalloc might degrade application performance somebit, due to tracemalloc own overheads. Be mindful about its use in production environments.</p>
<p>If you are interested in digging deeper into Python Object Memory Allocation Internals and debugging memory leak, have a look at an Interesting talk by <a href="https://www.linkedin.com/in/sanketplus/">Sanket Patel</a> in PyCon India 2019, <a href="https://www.youtube.com/watch?v=s9kAghWpzoE">Debug Memory Leak In Python Flask | Python Object Memory Allocation Internals</a></p>
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