DevOps is not just a tool or service, its a methodology/culture which allows the development and operations team to work together as a team.

1.What is Devops? Devops is not just tool or a service,its a culture that is overtaking the business world.

Q1. What are differences between the git distributed model and svn server-client model? Git is open source distributed vice control system whereas Apache Subversion is an open source software version and revision control system under Apache license Git has a Distributed Model. But SVN has a Centralized Model. In git every user has their own copy of code on their local like their own branch but In SVN there is central repository has working copy that also make changes and committed

Components of Docker and its Brief Summary Docker has below components.  dockerd – is a docker daemon which listens for docker API requests using three different types of sockets(unix, tcp and fd)  Containerd – is responsible for managing container lifecycle. It takes care of image push/pull, managing storage, invoking execution of containers, managing network primitives RunC – is command-line client for running applications packed according to OCI format and is a compliant implementation of the OCI What is the differenece

Docker –version         gives the version of docker that’s being used Docker pull                 to pull an image from the registry Docker run <image>  to create a container Docker ps                    list of running containers Docker ps –a               shows all the running and exited containers Docker stop                stop a running container gracefully Docker kill                  stops a running container abruptly Docker commit           creates a new image of an edited container Docker push                used to push an image

CMD is an instruction given in the dockerfile which is executed in the container when the image is run. When two CMD instructions are given in the dockerfile, the latest one is executed. Entrypoint is similar to CMD except that when more instructions are given all are appended.    Dockerfile should specify at least any one of the CMD or Entrypoint commands.

Dockerfile is a simple text file which is a collection of commands and instructions that are used to build a docker image. The Docker build command is used to build docker images using the instructions mentioned in the dockerfile.

Docker exec command is used to access the contents of a container and runs the commands inside the container. Docker attach command is used to attach our terminal to a running container to view it’s working.

Docker stop stops the running container by gracefully stopping step by step whereas docker kill abruptly stop a running container.

Docker pause is used to pause or suspend a running container or containers depending on the input. This puts a pause on all running operation happening at that instance. Docker unpause simply resumes the operations in the container.

A docker consists of      Docker client which puts up the request for the client in order to perform a request.      Docker host which contains the docker daemon. The requests which are put up by the client are processed here i.e containers are created and images are pulled from docker registry/hub. Docker registry is the place where the different apps images are stored. These images are pulled to the host where they are processed by creating a container.

Docker psThis command is used to list all the running containers in the background. Docker ps -aThis command is used to know the details of all the running, stopped, or exited containers. Docker versionWe usually start by finding the installed version of docker that we are working on. Docker pullAs the name suggests, this command pulls a specific image from the Docker Hub. All you have to do is use the command ‘docker pull’ along with the name of the

CMD InstructionYou can set default commands with parameters using the CMD instruction. If you run a Docker container without specifying any additional CLI commands, the CMD instruction will be executed. You can include an executable as the default command. However, if you choose to omit it, you will have to specify an ENTRYPOINT instruction along with the CMD instruction If you have specified an argument along with the Docker run command, the default one specified using the CMD instruction will

FROM: Create a basic image like httpd. RUN: It is to build the container MAINTAINER: Creates the images. ENV: Environment for image. COPY: Copies the file to images.

Docker attachThis command to attach your terminal’s standard input, output, and error (or any combination of the three) to a running container using the container’s ID or name. attach the running container with the following command. you need to press enter once execute the below command, docker is waiting for your input. docker attach nodeapi once attached, you can do all the cli commands like you can check the node version, run the bundle file, exit etc.. But the problem

docker stop attempts to gracefully shutdown container(s) while docker kill (by default) immediately stops/terminates them; docker stop issues a SIGTERM signal to the main process inside the container docker kill (by default) issues a SIGKILL signal. With docker kill, you may specify to send a different signal (to the main process inside the container) than the default SIGKILL signal, using the –signal flag. Same thing is not possible with the docker stop command. With docker stop, the container(s) must comply

Docker Pause: It will suspends all processes in the specified containers. It means that the processes in the container stop running, and they are be able to resumed later. docker pause [container id or name] Docker Unpause: It will resumes all the processes in the specified container. It means recovery container all processes. docker unpause [container id or name]

Docker Client: The first component of Docker is the client, which allows the users to communicate with Docker. Being a client-server architecture, Docker can connect to the host remotely and locally. As this component is the foremost way of interacting with Docker, it is part of the basic components. Whenever a user gives a command to Docker, this component sends the desired command to the host, which further fulfils the command using the Docker API. Docker Image: Docker images are

-> docker –versionThis command is used to get the currently installed version of docker-> docker pullThis command is used to pull images from the docker repository-> docker runThis command is used to create a container from an image-> docker psThis command is used to list the running containers-> docker ps -aThis command is used to show all the running and exited containers-> docker execThis command is used to access the running container-> docker stopThis command stops a running container-> docker

The ENTRYPOINT instruction looks almost similar to the CMD instruction. However, the main highlighting difference between them is that it will not ignore any of the parameters that you have specified in the Docker run command (CLI parameters).-> CMD : Sets default parameters that can be overridden from the Docker Command Line Interface (CLI) when a container is running.-> ENTRYPOINT : Default parameters that cannot be overridden when Docker Containers run with CLI parameters.