How to Use the kubectl exec Command

kubectl exec runs a command inside a container of a running pod. It is like docker exec for Kubernetes, and it is one of the main tools for troubleshooting, checking configuration and maintenance.

You need kubectl installed and access to a cluster.

Syntax

kubectl exec [OPTIONS] POD_NAME -- COMMAND [args...]

• kubectl is the client for the cluster.
• exec runs a command in a container of a pod.
• OPTIONS are flags such as -it, -c <container> or --namespace.
• POD_NAME is the pod.
• -- separates the kubectl options from the command that runs in the container. It is required.
• COMMAND is what to run, such as sh, bash or ps.
• args are the arguments of that command.

1. Run a simple command

List the files in the working directory of the container:

kubectl exec my-pod -- ls -la

Print the current directory:

kubectl exec my-pod -- pwd

2. Open an interactive shell

kubectl exec -it my-pod -- /bin/bash

-i keeps standard input open and -t allocates a terminal. You can then run many commands.

Minimal images such as Alpine do not have bash. Use sh:

kubectl exec -it my-pod -- /bin/sh

To see which shells exist:

kubectl exec my-pod -- ls -la /bin/*sh

3. Choose the container in a multi-container pod

kubectl exec -it my-pod -c container-name -- /bin/bash

If you skip -c, kubectl uses the first container (or the default one set by an annotation). List the containers:

kubectl describe pod my-pod

4. Use another namespace

kubectl exec -it my-pod -n my-namespace -- /bin/bash

5. Show environment variables

kubectl exec my-pod -- env

This helps when you debug configuration problems.

6. Work with files

Read a file:

kubectl exec my-pod -- cat /etc/hostname

Create a file:

kubectl exec my-pod -- touch /tmp/testfile

Check disk usage:

kubectl exec my-pod -- df -h

Find files:

kubectl exec my-pod -- find /var/log -name "*.log"

7. Network checks

Run a temporary pod and ping an address:

kubectl run pingbox --image=busybox -it --restart=Never -- ping 8.8.8.8

8. Read logs and config files

kubectl exec my-pod -- tail -f /var/log/apt/term.log

kubectl exec my-pod -- cat /etc/nginx/nginx.conf

kubectl exec my-pod -- find /var -name "*.log"

9. Install tools for debugging

kubectl exec my-pod -- apt-get update

kubectl exec my-pod -- apt-get install -y curl wget

10. Reload and test a configuration

kubectl exec nginx-pod -- nginx -s reload

kubectl exec nginx-pod -- nginx -t

11. Files and directories

kubectl exec my-pod -- mkdir -p /tmp/test

kubectl exec my-pod -- chmod 755 /etc/nginx/nginx.conf

kubectl exec my-pod -- find /app -name "*.log"

FAQ

What is the difference between kubectl exec and docker exec? kubectl exec works on pods in a cluster. docker exec works on Docker containers on one host.

Can I use another namespace? Yes, with -n or --namespace.

Which container does it use in a multi-container pod? The default one. Use -c to choose.

What does "exit code 126" mean? The command or shell does not exist in the container. Try /bin/sh instead of /bin/bash.

Can I exec into a pod that is not running? No. Check with kubectl get pods.

Can I set a timeout? Use the --request-timeout option or wrap the command in timeout 30 ... inside the container.

Quick recap

• kubectl exec POD -- COMMAND runs one command.
• kubectl exec -it POD -- sh opens a shell.
• Use -c for the container and -n for the namespace.