In Kubernetes, the standard way to execute a command inside a running container iskubectl exec, which is whyAis correct. kubectl exec calls the Kubernetes API (API server), which then coordinates with thekubeleton the target node to run the requested command inside the container using the container runtime’s exec mechanism. The -- separator is important: it tells kubectl that everything after -- is the command to run in the container rather than flags for kubectl itself.

This is fundamentally different from docker exec. In Kubernetes, you don’t normally target containers through Docker/CRI tools directly because Kubernetes abstracts the runtime behind CRI. Also, “Docker” might not even be installed on nodes in modern clusters (containerd/CRI-O are common). So optionBis not the Kubernetes-native approach and often won’t work.

kubectl run (option C) is for creating a new Pod (or generating workload resources), not for executing a command in an existing container. kubectl attach (option D) attaches your terminal to a running container’s process streams (stdin/stdout/stderr), which is useful for interactive sessions, but it does not execute an arbitrary new command like exec does.

In real usage, you often specify the container when a Pod has multiple containers: kubectl exec -it -c -- /bin/sh. This is common for debugging, verifying config files mounted from ConfigMaps/Secrets, testing DNS resolution, or checking network connectivity from within the Pod network namespace. Because exec uses the API and kubelet, it respects Kubernetes access control (RBAC) and audit logging—another reason it’s the correct operational method.

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