reorganise course folders

courses/level101/metrics_and_monitoring/best_practices.md

@@ -0,0 +1,40 @@
+##
+
+# Best practices for monitoring
+
+When setting up monitoring for a service, keep the following best
+practices in mind.
+
+-   **Use the right metric type** -- Most of the libraries available
+     today offer various metric types. Choose the appropriate metric
+     type for monitoring your system. Following are the types of
+     metrics and their purposes.
+
+    -   **Gauge --** *Gauge* is a constant type of metric. After the
+         metric is initialized, the metric value does not change unless
+         you intentionally update it.
+
+    -   **Timer --** *Timer* measures the time taken to complete a
+         task.
+
+    -   **Counter --** *Counter* counts the number of occurrences of a
+         particular event.
+
+ For more information about these metric types, see [Data
+ Types](https://statsd.readthedocs.io/en/v0.5.0/types.html).
+
+-   **Avoid over-monitoring** -- Monitoring can be a significant
+     engineering endeavor***.*** Therefore, be sure not to spend too
+     much time and resources on monitoring services, yet make sure all
+     important metrics are captured.
+
+-   **Prevent alert fatigue** -- Set alerts for metrics that are
+     important and actionable. If you receive too many non-critical
+     alerts, you might start ignoring alert notifications over time. As
+     a result, critical alerts might get overlooked.
+
+-   **Have a runbook for alerts** -- For every alert, make sure you have
+     a document explaining what actions and checks need to be performed
+     when the alert fires. This enables any engineer on the team to
+     handle the alert and take necessary actions, without any help from
+     others.