Kubernetes for SysAdmins

Summary

Some of my K8 learnings and exam preparation. Anypne preparing for exam, would recoment Udemy cource by Mumshad.

• Samples : Basic K8 templates, ideal for starter and exam practice
• Vagrant. : Vagrant Kubernetes environment. (Not sure who wrote it, it works)
• Mycompany : Helm chart2 sample charts with configmaps

Development Principle

Exam tips

Kubectl auto complete alias k=kubectl; complete -F __start_kubectl

Kube Config

• Get current context k config current-context
• Set context and namespace k config set-context newcontext --namespace=newns
• View current configuration k config view
• Read config from a file k config view --kubeconfig=/newconf.txt

Useful commands

Make use of --dry-run and -o yaml, sometimes easier to edit yaml and apply it.

Create simple pod running Nginx

k run nginx --image=nginx --restart=Never --dry-run -o yaml 
--restart=Alyays  Creates Deployment
--restart=OnFailure  Creates a Job

Create Deployment with 4 replicas

k create deploy deploy1 --image=nginx --dry-run -o yaml 
k scale --replicas=4 deploy/deploy1 

Create Service to expose Deploy1 running port 80, on NodePort=32005

NodePort cannot be specified at command prompt, edit Yaml add nodePort then apply. Or use k create and add matching labels for your deployment.

k expose deploy deploy1 --name=deploy-service --type=NodePort --port=80 --dry-run -o yaml

Edit yaml and add "nodePort=32005" in ports section and apply config.