Kubernetes

• Design
• Operation
• Run a container with kubectl
• Use Port Forwarding to Access Applications in a Cluster
• Troubleshooting
• Links & Tools

Design

Operation

Run a container with kubectl

In Docker you can run a one-time container with the following

docker run --rm -it centos /bin/bash

To use the same in Kubernetes you need to use kubectl in any cluster

kubectl run tmp-shell --restart=Never --rm -i --tty --image centos -- /bin/bash

Links

For mor information in general:
kubectl for Docker Users

Use Port Forwarding to Access Applications in a Cluster

If you need to connect directly to a tcp-port in a pod you can do this with port forwarding.

So for example to access the redis pod in the namespace redis you will use this on the client:

kubectl port-forward redis1-master-0 6379:6379 -n redis

"redis1-master" is the pod name.

You can then access redis with a client to localhost:6379

Get pod names

To get all pod names from namespace redis use the following:

$ kubectl get pods -n redis
NAME                READY   STATUS    RESTARTS   AGE
redis1-master-0     1/1     Running   0          39h
redis1-replicas-0   1/1     Running   0          39h
redis1-replicas-1   1/1     Running   0          39h
redis1-replicas-2   1/1     Running   0          39h

Links

https://kubernetes.io/docs/tasks/access-application-cluster/port-forward-access-application-cluster/

Troubleshooting

Links & Tools