Disk that is not a volume.
WHAT IT IS
Space a container uses on the node's disk: the writable layer, temporary directories, and logs.
WHY IT MATTERS
It is finite, shared between everything on the node, and easily exhausted.
WHAT CONSUMES IT
Files written inside the container Temporary directories Container logs Downloaded images
WHAT HAPPENS WHEN A NODE RUNS SHORT
Pods are evicted, and they move elsewhere.
WHY THAT SPREADS THE PROBLEM
The same behaviour fills the next node.
WHAT TO SET
Ephemeral storage requests and limits, where the platform supports them.
WHAT EXCEEDING A LIMIT CAUSES
The pod being evicted.
WHAT TO DO ABOUT APPLICATIONS WRITING HEAVILY
Give them a volume instead.
WHAT TO USE FOR GENUINELY TEMPORARY DATA
A memory-backed temporary volume, sized deliberately.
WHAT TO BE CAREFUL WITH THERE
It consumes memory, counted against the pod's limit.
WHAT TO CONFIGURE ON NODES
Log rotation Image cleanup thresholds
WHAT TO MONITOR
Node disk use, with warning well before full.
WHAT TO CHECK WHEN PODS ARE EVICTED UNEXPECTEDLY
Node conditions, which state which resource was under pressure.
WHAT THE COMMONEST CAUSE IS
Logs nobody rotated.
