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One docker rm -f took down my whole k3s cluster
Freeing a busy port with docker rm -f by filter removed the external Postgres that holds my k3s cluster state: about 20 minutes of total outage. How k3s datastores work, why recovery was quick, and the guard rails I added.
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NetworkPolicy gotchas: hostNetwork Traefik and Docker DNAT
A hostNetwork ingress shares the node IP with everything on the host, and Docker rewrites destinations before kube-router filters egress. What that broke on my k3s cluster, how a forged header created an admin, and how to write exact policies.
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Velero said Completed. It had backed up a RAM disk.
Velero's Kopia backup skipped my main Postgres because it used hostPath, saving only an in-memory temp volume; 13 of 17 databases had no backup anywhere. PV fixes, two OOM kills, and a byte-exact restore.
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On single-node Kubernetes, RollingUpdate can mount your database twice
With one replica, RollingUpdate starts the new pod before stopping the old, and on a single node both mount the same ReadWriteOnce volume. How I audited 123 Deployments, fixed 15 with zero downtime, and what really slowed Qdrant.