One Registry to Rule Them All: Harbor as the Single Image Entry Point for a Bare-Metal k3s Cluster
If you run a Kubernetes cluster seriously, you eventually hit the Docker Hub wall. One morning your CI pipeline starts failing with toomanyrequests: You have reached your pull rate limit. Or worse — it fails during a cluster recovery at 2 AM, when your nodes are pulling images to restart critical workloads and Docker Hub decides you've exceeded your 100-pulls-per-6-hours anonymous quota.
The standard advice is to add authentication. But that only raises the limit — it doesn't eliminate the dependency on an external service during your most vulnerable moments. The production answer is a pull-through proxy cache, and on a self-hosted k3s cluster, Harbor + k3s mirrors makes every node behave as if Docker Hub were local.