NodeFilesystemAlmostOutOfFiles alert troubleshooting in OpenShift Container Platform 4

Issue

NodeFilesystemAlmostOutOfFiles alert is firing in the cluster

The NodeFilesystemAlmostOutOfFiles alert is similar to the NodeFilesystemSpaceFillingUp alert, but rather than being based on a prediction that a filesystem will run out of inodes in a certain amount of time, it uses simple static thresholds. The alert triggers at a warning level when 5% of available inodes remain, and triggers at a critical level when 3% of available inodes remain.

When a node's filesystem becomes full, it has a widespread impact. This issue can cause any or all of the applications scheduled to that node to experience anything from degraded performance to becoming fully inoperable. Depending on the node and filesystem involved, this issue could pose a critical threat to the stability of the cluster.