Pod on Micha Kops' Tech Notes

Setting up a Kubernetes Master Node

Fri, 14 May 2021 00:00:00 +0200

Goals

Initialize the cluster on the master node

sudo kubeadm init --pod-network-cidr=10.244.0.0/16

This might take a few minutes … afterward we set up our local kubeconfig:

mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config

Shows that the cluster is responding and kubectl working:

kubectl version

Mon, 01 Mar 2010 00:00:00 +0100

Simple steps for remote debugging a Java process running on a k8 pod:

Edit deployment and add the following parameters to the Java start line: -agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=127.0.0.1:5005

Also add the following port mapping at the section container → ports in the deployment:
```
- containerPort: 5005
  protocol: TCP
```
Safe, wait for the new pods and then add a port forward for port 5005 for this pod:
```
kubectl port-forward podname 5005
```

Mon, 01 Mar 2010 00:00:00 +0100

You need to have jq installed to use this snippet!

kubectl --context=my-context -n my-namespace get secret my-secret-name -o json | jq '.data | map_values(@base64d)'

kubectl replace deletes the old job, if there is any error, your job definition is lost, don’t forget to save it first!

Replace an existing Job with itself

kubectl get job JOBNAME -o yaml | kubectl replace --force -f -