Tutorial to get started with some kubectl commands and a kube-manifest.yaml to create and manage a single-node cluster using docker-for-desktop for Kubernetes integrated with Docker for Mac version with Engine: 19.03.4 and Kubernetes: v1.14.7 at release time of this project.

• Deploy a new Docker stack (default orchestrator is Kubernetes): docker stack deploy -c docker-compose.yaml nginx

• Stop stack docker stack rm nginx

• Kubernetes version: kubectl version

• Config view: kubectl config view

• Get config contexts: kubectl config get-contexts

• Set a config context (e.g. docker-for-desktop): kubectl config use-context docker-for-desktop

• Get cluster information: kubectl cluster-info

• View nodes in the cluster: kubectl get nodes

• Get deployments: kubectl get deployments

• Get pods: kubectl get pods

• Enables direct access to the API with proxy: kubectl proxy

• The most common operations can be done with the following kubectl commands:

  kubectl get <resource> - list resources

  kubectl describe <resource> - show detailed information about a resource

  kubectl logs <pod_name|type/name> - print the logs from a container in a pod

  kubectl exec <pod_name> <command> - execute a command on a container in a pod

• Apply filter to kubectl to sort by (e.g. get Replica Sets sorted by creation date):

  kubectl get rs --sort-by=.metadata.creationTimestamp

• Example to scale up a Deployment resource:

  kubectl scale deployments/kubernetes-bootcamp --replicas=4

For more info about these commands and learn some basics: https://kubernetes.io/docs/tutorials/kubernetes-basics/ Getting started with Kubernetes guide: https://theithollow.com/2019/01/26/getting-started-with-kubernetes/

https://kubernetes.io/docs/reference/kubectl/cheatsheet/

https://kubernetes.io/docs/reference/generated/kubectl/kubectl-commands

• Pods - Step 1: Create a manifest to start understanding Pods as a single unit (https://theithollow.com/2019/01/21/kubernetes-pods/)

  Pod docs: https://kubernetes.io/docs/concepts/workloads/pods/init-containers/

  • Deploy kubernete: kubectl apply -f kube-manifest.yaml

  • Delete kubernete resource: kubectl delete -f kube-manifest.yaml

  kubectl get pods or kubectl get pods --show-labels to show the Pods' labels

  kubectl describe pod [pod name] or kubectl get pods [pod-name] -o yaml to get the ouput in yaml format

  • Notes:

    • You can only horizontally scale stateless Pods. If you have stateful Pods (horizontal) scaling up/down is not possible

    • To create stateless apps check 12factor app (https://12factor.net/)

• Replica Set - Step 2: Deploy a Replica Set for replicating Pods (https://theithollow.com/2019/01/28/kubernetes-replica-sets/)

  Replica set docs: https://kubernetes.io/docs/concepts/workloads/controllers/replicaset/

  kubectl delete po [pod name] &

  Run kubectl get pods to see the state of replicating during the Pod deleting

• Deployments - Step 3: Deployment object construct a level above replica sets and actually manage the replica set objects (https://theithollow.com/2019/01/30/kubernetes-deployments/)

  Deployment docs: https://kubernetes.io/docs/concepts/workloads/controllers/deployment/

  Deploy update on deployment object: kubectl apply -f kube-update-deployment.yaml

  kubectl get po; kubectl get deploy

  For larger updates better keep tracking with kubectl rollout status deployment [deployment name]

  Update image container of the deployment object (e.g. Update nginx image to nginx:1.15.1-alpine version):

  kubectl set image deployment [deployment name] nginx=nginx:1.15.1-alpine

  See rollout history status: kubectl rollout history deployment [deployment name]

  We can remove the update running kubectl delete -f kube-update-deployment.yaml

• Services and Labels - Step 4: Deploy Service object to front-end Pods (https://theithollow.com/2019/01/31/kubernetes-services-and-labels/)

  Services docs: https://kubernetes.io/docs/concepts/services-networking/service/#defining-a-service

  kubectl get services

  kubectl get pods -o wide

  Given the declaration that nodePort: 30001 we can access our nginx server at http://localhost:30001

• Endpoints and External services - Step 5: Verify and create external endpoint service (https://theithollow.com/2019/02/04/kubernetes-endpoints/)

  Endpoint docs: https://kubernetes.io/docs/concepts/services-networking/endpoint-slices/

  kubectl get endpoints