Docker build fails inode exhausted
A self-hosted CI runner host starts failing jobs at 09:00 with 'no space left on device' during `docker build` and `git checkout`, but `df -h` on /var/lib/docker shows only 40% bytes used. `df -i` shows that filesystem at 100% inodes. The host runs hundreds of short-lived containers a day; image pulls and intermediate build layers (each a tree of many small files in overlay2) have accumulated, and `docker image prune`/container cleanup has never been scheduled. No deploy — just steadily more pipelines over months. Triage and recover.
What a strong answer looks like
Stop the bleeding first (mitigate), then form hypotheses from real signals. Separate root cause from symptom, communicate status as you go, and close with what prevents a repeat.
0:00 of about 30 min
Which questions mattered is sealed until you submit. Telling you now would just be handing over the edge cases.
Run or narrate your approach, then ask the coach.