Moving Logic Out of Pods: Extending the Argo Workflows Controller

Argo Workflows typically runs every step as its own Kubernetes pod, which is great for isolation but expensive for fast, lightweight tasks. This article explains the Executor Plugin mechanism—an HTTP contract that lets you extend the Argo controller without maintaining a fork—by moving step execution into a reusable agent pod. It walks through enabling plugins in the controller, implementing a minimal plugin server (with examples), registering plugins via ConfigMaps, and tightening security with token checks, ServiceAccounts, and RBAC (including WorkflowTaskSet). The result: fewer pods, lower scheduler load, and a clean extension path for custom workflow behavior.