A container runs fine at first… then slowly degrades. No spikes. No crashes. Just silent slowness.
Root cause
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Layered filesystem (OverlayFS) grows
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Log files inside containers never rotate
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Memory fragmentation inside long-lived containers
Golden rule
Containers are not VMs. They are disposable.
Fix
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Never log to disk inside containers
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Use external logging drivers
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Restart containers periodically (even healthy ones)
logging:
driver: "json-file"
options:
max-size: "10m"
max-file: "3"