How a 1 GiB Memory Limit Took Down My Entire k3s Cluster (opens in new tab)

Originally published at woitzik.dev It started with Paperless-ngx crashing. It ended with my control-plane node sitting at a load average of 90, CoreDNS generating 1.2 million DNS queries per day, and worker nodes reporting 3.8 GiB of allocatable memory instead of the 16 GiB they actually had. The root cause of all of it: a single 1 GiB memory limit set three months earlier without much thought. This is the full post-mortem — not the sanitized version where everything was obvious in hindsight...