A POD is a collection of container and its storage inside a node of kubernetes cluster. We can have single or multiple container inside POD.

Create a pod.yaml file with list of lines needs to be executed

kubectl create -f pod.yaml => Will create pod now

kubectl get pods => To see list of pods

Replication controller is responsible for making sure that the specified number of pod replicas are running at any point of time. It is used for managing POD life cycle. It is used to make sure specified number of pod is running or atleast one POD is running. It has ability to bring up or down the specified no of pod. If there are too many pods, the replication controller has ability to terminate extra pods.

to create namespace => kubectl create ns namespacename

To see list of namespaces => kubeclt get ns

To descibe namespace => kubectl describe ns namespcename

To create replication controller => kubectl create -f rc.yaml -n=namespacename

To update/ apply changes to resources => kubectl apply -f rc.yaml -n=namespacename

To delete replication controller => delete rc replicationcontroller-example -n=namespacename

3.What is ReplicaSets – in 4 lines with 1 YAML example?

Replica set is used to maintain number of running state of pods. It helps to ensure specified number of pod replicas are running at any given time.

To create replicaset => kubectl apply -f example.yaml

To see list of replicassets deployed => kubectl get rs

To see state of replicaset => kubectl describe rs/example

To see list of pods => kubectl get pods

4.What is Deployment – in 10 lines with 1 YAML example?

A deployment provides declarative updates for pods and replicasets.

features of deployment => replication + controller + versioning + zero time rollout + zero time rollback

To create deployment => kubectl create deployment my-dep –image=scmgalaxy/nginx-devopsschoolv1 -n=vishnu

type of deployment can be 2 ways => Recreate & Rolling Update

Recreate => Before creating new one all existing pods will be terminated. while doing deployment, it will ensures older version of pod has terminated before creating a new Pods.

Rolling Update => The update strategy will be taken care pod-by-pod and so greater system can remain active.

Docker is container/Management Platform tool. It helps to save cost & time and improve quality as well. It will helps to run lots of application in less CPU & RAM compare to any other physical server.

2. What is Container?

In older days to run application virtual machine has been used. If we want to run 100s of application then we need 100 Virtual machine and each Virtual machine will require OS and each OS will consume RAM & boot system. In container model, one OS we can have multiple user and each user run their own number of applications. In this way consumption of RAM, memory and operating cost will be reduced. Container will have bundles of all software executables to run application.

3. Top 10 commands with 1 example of using docker container

1. docker images -> To see list of images available in docker system

2. docker ps -> To see list of all running containers

10. docker rm containername -> To remove container

12. docker run -itd imagename -> Create container from an image

1. docker pull imagename => To pull image from repository

4. docker tag imagename reposiotryname (docker tag vishnu tvishnup/vishnupriya) => To tag image to reposiotry

5. docker build -t imagename . (docker build -t vishnudockerimage .) => To build an image

5. five commands with 1 example of using docker registry?

1. docker run -d httpd => To create container in faster way (It will create container & pull image from reposiotry)

2. docker tag imagename reposiotryname (docker tag vishnu tvishnup/vishnupriya) => To tag image to reposiotry

3. docker pull imagename => To pull image from repository

4. docker push username/repository => To push image to repository

5. docker login => To login to hub repository

6. docker logout => To logout from hub repository

7. docker commit -m”up-up-git-apache” 5fd8e4229356 vishnu=> It will create layer with combination of git , apache & java images inside container called 5fd8e4229356