iDeepesh / goKubernetes

Building container image and running it locally

• docker-machine start default
• eval $(docker-machine env default)
• go build -o main .
• docker build -t scratch-app -f Dockerfile .
• docker run --publish 7080:7080 -it scratch-app
• Test from docker host:
  • docker-machine ssh default
  • curl localhost:7080/Arya
• OR test from your laptop running docker-machine host
  • docker ps | grep scratch-app
  • docker-machine ip default
  • curl IP_RETRIVED_IN_PREVIOS_STEP:7080/Arya

Tagging the image and uploading to hub.docker.com

• docker images
• docker tag 0cf5c5dbd51f ideepesh/k8s-demo:v2
• docker push ideepesh/k8s-demo
• docker tag 0adflkadfjlf ideepesh/k8s-demo:latest
• docker push ideepesh/k8s-demo

Running the image in kubernetes for single pod

• minikube start
• cd basics
• kubectl create -f config/k8sDemoOnePod.yml
• kubectl get pods
• kubectl get pod scratch-app
• kubectl describe pod scratch-app
• Expose service:
  • kubectl expose pod scratch-app --type=NodePort --name scratch-app-pod-svc
  • kubectl get service
  • kubectl describe service scratch-app-pod-svc
  • minikube service scratch-app-pod-svc --url
  • curl URL_RETRIEVED_WITH_PREVIOUS_COMMAND/Arya
• kubectl exec scratch-app -- ANY_COMMAND
• kubectl delete service scratch-app-pod-svc
• kubectl delete pod scratch-app

Running the image in kubernetes with replication controller

• minikube start
• cd basics
• kubectl create -f config/k8sDemoReplicas.yml
• kubectl get replicationcontrollers
• kubectl describe rc scratch-app-controller
• kubectl get pods
• kubectl scale --replicas=3 -f config/k8sDemoReplicas.yml
• kubectl scale --replicas=4 replicationcontroller scratch-app-controller
• Expose service
  • kubectl expose rc scratch-app-controller --type=NodePort --name scratch-app-rc-svc
  • kubectl get service
  • kubectl describe service scratct-app-rc-svc
  • minikube service scratch-app-rc-svc --url
  • curl URL_RETRIEVED_WITH_PREVIOUS_COMMAND/Arya
• kubectl delete service scratch-app-rc-svc
• kubectl delete replicationcontroller scratch-app-controller

Running the image in kubernetes with deployment

• minikube start
• cd basics
• kubectl create -f config/k8sDemoDeployment.yml
• kubectl get deployments
• kubectl describe deployment scratch-app-deployment
• kubectl get replicaset
• kubectl describe rs XXXXX
• kubectl get pods
• kubectl
• Expose service
  • kubectl expose deployment scratch-app-deployment --type=NodePort --name scratch-app-dep-svc
  • kubectl get service
  • kubectl describe service scratct-app-dep-svc
  • minikube service scratch-app-dep-svc --url
  • curl URL_RETRIEVED_WITH_PREVIOUS_COMMAND/Arya
• kubectl set image deployment/scratch-app-deployment k8s-demo=ideepesh/k8s-demo:v1
• kubectl rollout status deployment/scratch-app-deployment
• curl URL_RETRIEVED_WITH_PREVIOUS_COMMAND/Arya
• kubectl rollout undo deployment/scratch-app-deployment
• kubectl rollout status deployment/scratch-app-deployment
• curl URL_RETRIEVED_WITH_PREVIOUS_COMMAND/Arya
• kubectl delete service scratch-app-dep-svc
• kubectl delete deployment scratch-app-deployment

Creating service from config file

• minikube start
• cd basics
• kubectl create -f config/k8sDemoDeployment.yml
• kubectl get deployments
• kubectl create -f config/k8sDemoSvc.yml
• kubectl get service
• minikube service scratch-app-dep-svc --url
• curl URL_RETRIEVED_WITH_PREVIOUS_COMMAND/Arya
• kubectl delete service scratch-app-dep-svc
• kubectl delete deployment scratch-app-deployment

Using Node selectors:

• minikube start
• cd basics
• kubectl get nodes
• kubectl get nodes --show-labels
• kubectl create -f config/k8sDemoDepNodeSelector.yml
• kubectl get po
• kubectl get deploy
• kubectl describe po
• kubectl label nodes minikube hardware=commodity
• kubectl get nodes --show-labels
• kubectl get po
• kubectl label nodes minikube hardware=commodity
• kubectl get po
• kubectl delete po ANY_ONE_POD
• kubectl get po
• kubectl delete deployment scratch-app-dep-node-selector

Adding secrets with volumes

• minikube start
• cd basics
• create -f config/secrets/my-secrets.yml
• kubectl create -f config/secrets/my-secrets.yml
• kubectl create -f config/k8sDemoDepSecretsVolume.yml
• kubectl get po
• kubectl describe pod scratch-app-deployment-5bf9dc78f7-2hrbh
• kubectl exec scratch-app-deployment-5bf9dc78f7-2hrbh -it -- /bin/bash
  • cd /etc/credentials/
  • cat username
  • cat password
  • mount
  • exit
• kubectl delete secrets user-secrets
• kubectl delete deployment scratch-app-dep-secretes-volume

Running redis in docker container

• docker run --name my-redis-container -p 7001:6379 -d redis
• docker ps | grep my-redis-container
• docker-machine ip default
• redis-cli -h IP_OF_THE_DOCKER_MACHINE_HOST -p 7001
• docker rm -f my-redis-container

Running the redis and app as separate containers in same pod in kubernetes

• minikube start
• cd appAndRedis
• kubectl create -f config/k8sRedisPod.yml
• kubectl get pods
• kubectl get pod redis-app
• kubectl describe pod redis-app
• kubectl create -f config/k8sRedisSvc.yml
• kubectl get service
• minikube service redis-app-service --url
• redis-cli -h IP_OF_THE_SERVICE -p 32002
• curl APP_URL_RETRIEVED_IN_PREVIOUS_COMMAND:32001/Arya
• kubectl delete service redis-app-service
• kubectl delete pod redis-app

Running the redis and app in separate pods in kubernetes. Sevice discovery via env variables.

• minikube start
• cd svcDiscEnvVar
• kubectl create -f config/k8sRedisPod.yml
• kubectl describe pod redis-pod
• kubectl create -f config/k8sRedisSvc.yml
• kubectl get service
• kubectl create -f config/k8sRedisAppPod.yml
• kubectl describe pod redis-app-svc-disc
• kubectl logs redis-app-svc-disc
• kubectl create -f config/k8sRedisAppSvc.yml
• kubectl get service
• minikube service redis-app-service --url
• curl APP_URL_RETRIEVED_IN_PREVIOUS_COMMAND:32001/Arya
• kubectl delete service redis-app-service
• kubectl delete service redis--service
• kubectl delete pod redis-app-svc-disc
• kubectl delete pod redis-pod

Config map

• minikube start
• cd basics
• kubectl create -f config/configMap/user-config.yaml
• kubectl create configmap prop-config --from-file=config/configMaps/prop-config.properties
• kubectl create -f config/k8sDemoDepConfigMapVolume.yml
• kubectl get po
• kubectl describe pod scratch-app-deployment-5bf9dc78f7-2hrbh
• kubectl exec scratch-app-deployment-5bf9dc78f7-2hrbh -it -- /bin/bash
  • cd /etc/config/
  • cat username
  • cat email
  • cd /etc/properties/
  • cat prop-config.properties
  • mount
  • exit
• kubectl delete deployment scratch-app-dep-config-map-volume
• kubectl delete configmap user-config
• kubectl delete configmap prop-config

Using nginx as reverse proxy with configMap/volume specifying nginx configuration

• minikube start
• cd nginx
• kubectl create -f config/k8sRedisPod.yml
• kubectl describe pod redis-pod
• kubectl create -f config/k8sRedisSvc.yml
• kubectl get service
• kubectl create configmap nginx-config --from-file=config/reverseproxy.conf
• kubectl create -f config/k8sNginxDep.yml
• kubectl create -f config/k8sNginxSvc.yml
• kubectl get service
• minikube service nginx-service --url
• curl APP_URL_RETRIEVED_IN_PREVIOUS_COMMAND:32080/Arya
• kubectl delete service nginx-service
• kubectl delete deployment nginx-dep
• kubectl delete configmap nginx-config
• kubectl delete service redis-service
• kubectl delete pod redis-pod

Ingress controller with Nginx Ingress controller

• cd ingressCongroller
• minikube start
• minikube addons list
• minikube addons enable ingress
• kubectl create -f config/k8sRedisPod.yml
• kubectl create -f config/k8sRedisSvc.yml
• kubectl create -f config/mandatory.yaml
• kubectl create -f config/service-nodeport.yaml
• kubectl create -f config/k8sIngress.yml
• minikube ip
• curl IP_OF_CLUSTER
• curl IP_OF_CLUSTER/Sansa -H 'Host: foo.bar.com'
• curl IP_OF_CLUSTER/Sansa -H 'Host: bar.baz.com'
• curl IP_OF_CLUSTER/Arya -H 'Host: bar.baz.com'
• curl IP_OF_CLUSTER/Arya -H 'Host: foo.bar.com'
• kubectl delete namesapce ingress-nginx
• kubectl delete ingress ingress-resource
• kubectl delete service redis-app-service
• kubectl delete pod redis-app

Debugging tricks

• k8s: Simple port forwarding on localhost to pod:
  • kubectl port-forward FULL_POD_NAME 6080:7080
  • localhost:6080/Arya
  • Checks if the pod is working
• ssh into the docker-machine host
  • docker-machine ssh default
• Service discovery
  • kubectl get po --namespace=kube-system
  • kubectl run -i --tty busybox --image=busybox ---restart=Never -- sh
  • nslookup NAME_OF_ANY_SERVICE_CLUSTER