day23.md

On the twenty-third day, I learned the following things about Kubernetes.

• First update the machine by writing sudo apt-get update.

• Once the instance is created, write sudo su to go to the root user.

• First of all install the docker by writing sudo apt update && apt -y install docker.io

• Then install the kubectl by writing curl -LO https://storage.googleapis.com/kubernetes-release/release/$(curl -s https://storage.googleapis.com/kubernetes-release/release/stable.txt)/bin/linux/amd64/kubectl && chmod +x ./kubectl && sudo mv ./kubectl /usr/local/bin/kubectl

• Then install the minikube by writing curl -Lo minikube https://storage.googleapis.com/minikube/releases/latest/minikube-linux-amd64 && chmod +x minikube && sudo mv minikube /usr/local/bin

• Once the minikube is installed, start it by first writing apt install conntrack

• After that, type minikube start --vm-driver=docker and it will give you the following error.

• It is saying that docker should not be used with root privilege. To solve this problem, press CTRL+D to go out from root.

• After that, again type minikube start --vm-driver=docker and it will give you another following error.

• To solve this problem, type the following commands.

  sudo groupadd docker
  sudo usermod -aG docker $USER
  newgrp docker
  

• If it is still not working then visit this website that will show you more ways.

• Visit this link StackOverflow and it will show you the solution if you faced a problem.

• Once the commands are executed successfully, you will get the following result.

• If you type minikube status, it will show you running status.

Note: The above screenshots are executed by using the AWS instance but if you run these commands in your local machine then they will be successfully executed because I installed minikube on my local machine also using these commands.

• You can get more info about kubectl installation by visiting this page.

• You can get more info about minikube installation by visiting this page.

• minikube version will show the version of minikube.

• minikube dashboard will show you the minikube dashboard in your browser.

• minikube docker-env will give some environment variables that will help you to communicate with remote servers.

• minikube ssh will take you inside the minikube.

• docker container ls will show you the list of containers that are required for Kubernetes.

• docker ps will show you the list of containers that are required for Kubernetes.

• kubectl get pods will show you the pods that are running.

• kubectl get nodes will show you the nodes that are running.

• kubectl describe node node-name will show you the information about a particular node.

Data in YAML file

kind: Pod
apiVersion: v1
metadata:
  name: testpod
spec:
  containers:
    - name: c00
      image: ubuntu
      command: ["/bin/bash", "-c", "while true; do echo Hello-Bilal; sleep 5; done"]

• kubectl apply -f pod.yml will run the comands that are present in the yaml file.

• kubectl get pods -o wide will show you the exact location of the pods with their ip addresses.

• kubectl describe pod pod-name OR kubectl describe pod/pod-name will show each and every detail of a pod.

• kubectl logs -f pod-name will show you the information of the container(s) in a specific pod.

• kubectl logs -f pod-name -c container-name will show you the information of a specific container in a specific pod.

• kubectl exec pod-name -it -c container-name -- hostname -i will show you the ip the address of the pod that contain these containers.

• kubectl delete pod pod-name OR kubectl delete -f pod.yaml will delete a specific pod. A pod can either be deleted by pod-name or a filename that contains the pod information.

• Now write annotations for the description of a pod.

  kind: Pod
  apiVersion: v1
  metadata:
    name: testpod
    annotations:
      description: Our first test pod is created.
  spec:
  ...
  

• kubectl describe pod pod-name OR kubectl describe pod/pod-name will show each and every detail of a pod.

Data in YAML file for multiple containers

kind: Pod
apiVersion: v1
metadata:
  name: testpod2
spec:
  containers:
  - name: c00
    image: ubuntu
    command: ["/bin/bash", "-c", "while true; do echo Hello-Bilal; sleep 5; done"]
  - name: c01
    image: ubuntu
    command: ["/bin/bash", "-c", "while true; do echo Hello-Khan; sleep 5; done"]

• First apply the file by writing kubectl apply -f pod.yml

• kubectl exec pod-name -it -c container-name -- /bin/bash will move you inside the container.

• ps -ef will show you the things that are running inside the container.

• kubectl logs -f pod-name will show you the information of the container(s) in a specific pod.

• kubectl logs -f pod-name -c container-name will show you the information of a specific container in a specific pod.

Writing environment variables in YAML file

kind: Pod
apiVersion: v1
metadata:
    name: environment
spec:
  containers:
    - name: c00
      image: ubuntu
      command: ["/bin/bash", "-c", "while true; do echo Environment-variables; sleep 5; done"]
      env:
        - name: MYNAME
          value: Bilal

• First apply the file by writing kubectl apply -f pod.yml

• After going inside the container by this command kubectl exec pod-name -it -c container-name -- /bin/bash, type env to get the environment variables.

• After getting inside the container, type echo $MYNAME to get the environment variable value.

• kubectl config view will show you the information about the cluster.

• kubectl config current-context will display the current context.

• kubectl get all will show you the pods, services, deployment, replicaset etc.

• minikube stop will stop the minikube.

Explaining it in a video

Here you can get an explanation in a video. 23/60 Day of DevOps Challenge