gc-watchdog

Amazon DocumentDB Garbage Collection Watchdog

This tool monitors a DocumentDB cluster for garbage collection activity. It displays the start and end of each garbage collection to a log file and can optionally create 3 CloudWatch metrics for monitoring and alerting purposes.

Installation

Clone the repository

Requirements

• Python 3.7+
• PyMongo, boto3
  • IAM permission "cloudwatch:PutMetricData" is required to create CloudWatch metrics

Using the garbage collection watchdog

python3 gc-watchdog.py --uri <uri> --log-file-name <log-file-name> [--create-cloudwatch-metrics] [--cluster-name <cluster-name>]

• <uri> follows the MongoDB Connection String URI Format
• <log-file-name> is the name of the log file created by the tool
• include --create-cloudwatch-metrics to create metrics for the number of ongoing garbage collections, maximum time of an ongoing garbage collection in seconds, and total time of all ongoing garbage collections in seconds
  • CloudWatch metrics are captured in namespace "CustomDocDB" as "GCCount", "GCTotalSeconds", and "GCMaxSeconds"
• include --cluster-name <cluster-name> if capturing CloudWatch metrics via --create-cloudwatch-metrics
• NOTE - The default frequency to check for garbage collection activity is every 5 seconds. Garbage collections requiring less than 5 seconds might not be recorded by this tool.