Automating Cache Cleanup on K8s Cluster Nodes with Cron Job

This document explains how to set up a cron job to clear the cache on ubuntu systems.

Overview

Linux caches data in memory to improve performance, but over time, excessive caching can lead to high memory usage. To free up RAM, we can follow the below procedure.

Procedure

To optimize memory usage on RKE2 cluster nodes, a cron job can be scheduled to periodically clear the RAM cache using the following command.

sync; echo 3 > /proc/sys/vm/drop_caches

• Use sync to ensure all data is written to disk.

• echo 3 Clears page cache, dentries, and inodes.

Steps to add the cron job

1. Open the crontab file for editing as a root user. crontab -e

2. Add the following line to schedule the cache clearing every week. 0 0 * * 6 sync; echo 3 > /proc/sys/vm/drop_caches

3. Save and exit the editor.

4. Check if the cron job is added successfully. crontab -l

This cron job will run every week on saturday 12am, ensuring that RAM cache is cleared periodically to optimize memory usage on RKE2 nodes.