k8s awesome (Kubernetes Practical Cheat Sheet)

A small practical guide for everyday Kubernetes usage: copying files into containers, entering pods, and handling common real-world pitfalls.

Enter a container shell

1. Verify context

   kubectl config get-contexts
   kubectl config use-context my_CTX

2. List pods

   kubectl get pods -n my_NS

3. Enter pod shell (single container)

   kubectl exec -it my_POD -n my_NS -- sh

   or, if multiple containers:

   kubectl exec -it my_POD -n my_NS -c container-name -- sh

   
   

   ALL in ONE command:

   
   kubectl config use-context my_CTX && kubectl exec -it $(kubectl get pods -n my_NS --sort-by=.metadata.creationTimestamp -o name | grep api | tail -1) -n my_NS -- sh
   

Copy file from local machine to a container

1. Show all Kubernetes contexts and see which one is active (*)

   kubectl config get-contexts

2. Switch to the required context

   kubectl config use-context my_CTX

3. List namespaces (usually your application name)

   kubectl get namespaces

4. List pods in the namespace

   kubectl get pods -n my_NS

5. Check container names inside the pod

   kubectl get pod my_POD -n my_NS -o jsonpath='{.spec.containers[*].name}'

6. Copy a file into the pod (single container)

   kubectl cp /path/to/local/file.txt my_NS/my_POD:/path/in/container

7. Copy a file into a specific container (multiple containers)

   kubectl cp /path/to/local/file.txt my_NS/my_POD:/path/in/container -c container-name

Fix file permissions inside container (IMPORTANT)

Example:

chown app-data:app-data /var/www/app/var/*.csv

Pro tips

1. Debug containers are safer than touching app containers

   If your cluster supports it, prefer ephemeral debug containers:

   kubectl debug -it my_POD -n my_NS --image=busybox