Kubectl exec
Internal
Overview
Execute a command in a container:
kubectl exec <pod|type/name> [-c <container>] [flags] -- <command> [args...] [options]
Do not surround the command and its flags/arguments with quotes unless that is how it would execute normally (i.e., do ls -t /usr, not "ls -t /usr").
Example
Read-Only Commands
Get the date on the target pod:
kubectl exec my-pod date
Interactive Commands
Start a bash into the container, switch to raw terminal mode, send stdin to the bash process in pod my-pod and sends stdout/stderr from 'bash' back to the client:
kubectl exec my-pod -it -- bash -il
The Role of '--' on Command Line
The '--' is a sequence of characters that signals to kubectl to stop scanning command line for its own flags and options (sequences that start with -). This is particularly useful if the command to be executed has its own command line arguments that start with '-'. If the command you want to execute in the pod has any flags in common (e.g. -i), two dashes (--) must be used to separate the command's flags/arguments from kubectl's commands/arguments.
For example,
kubectl exec my-pod -it bash -c my-command
will fail because kubectl will interpret "-c" as a container name flag and try to look up "my-command" as a container in the pod - which will fail.
The correct command is:
kubectl exec my-pod -it -- bash -c my-command
which tells kubectl to execute "bash -c my-command" as command on the pod.
Flags
-c,--container=
The name of the container to execute the command into. If omitted, the first container in the pod will be chosen.
-i,--stdin=false
Pass stdin to the container.
-t,--tty=false
Stdin is a TTY
--pod-running-timeout=
The length of time (like 5s, 2m, or 3h, higher than zero) to wait until at least one pod is running.