Ensure Eviction threshold Settings Are Set - evictionHard: memory.available

Description

Two types of garbage collection are performed on an OpenShift Container Platform node:

• Container garbage collection: Removes terminated containers.
• Image garbage collection: Removes images not referenced by any running pods.

Container garbage collection can be performed using eviction thresholds. Image garbage collection relies on disk usage as reported by cAdvisor on the node to decide which images to remove from the node.

The OpenShift administrator can configure how OpenShift Container Platform performs garbage collection by creating a kubeletConfig object for each Machine Config Pool using any combination of the following:

• soft eviction for containers
• hard eviction for containers
• eviction for images

To configure, follow the directions in the documentation

This rule pertains to the memory.available setting of the evictionHard section.

Rationale

Garbage collection is important to ensure sufficient resource availability and avoiding degraded performance and availability. In the worst case, the system might crash or just be unusable for a long period of time. Based on your system resources and tests, choose an appropriate threshold value to activate garbage collection.