Docker Online Training | Kubernetes Online Training

1. Docker Containers & Components Definition Docker is a open source available platform which allows you to develop, ship and run your applications. It enables everyone to separate their applications from the infrastructure on which they are built thus making the software delivery process faster than the normal approach. So docker allows you to package and run your application in a isolated environment that is called as a container. The isolation and security makes it possible to run as many containers on your host machine. Docker provides us with a platform that helps manage the life cycle of the containers: 1) Firstly it allows to develop your application and its components using a container. 2) Secondly this container unit becomes the main unit of distribution or testing your application. 3) Thirdly, this can be deployed in production as a container or a service once you are ready. Now let us understand what a Docker engine is and what goes on inside it. it is a client server application with major components as: 1) Server - Which is the long running program called the daemon process. 2) REST API - Which is used by the programs to talk to the daemon and to instruct it what to do. 3) Command Line Interface - To type in the commands. The CLI uses the REST API to talk or control the docker daemon using CLI

2. commands. The daemon can create and manage docker objects such as the image, container, network or the volumes. Docker has a client-server architecture. The docker client communicates with the docker daemon, which usually build, run or distribute the containers. Docker client and daemon can run on same system or a docker client can communicate to a remote docker daemon. Both of them uses REST API, over UNIX sockets or a network interface to communicate. Let us see the different components one by one Docker Daemon It listens for the API requests from clients and also manages the docker objects such as images, containers, networks, and volumes. It communicates with otherdocker daemons to manage different docker services.

3. Docker Client It is the primary way used by many docker users to interact with docker. When commands are fired through CLI they are sent to dockerd, which carries them out. It uses the docker API and it can communicate with one or more daemons. Docker Registries It is used to store docker images. One such public registry is the Docker Hub. Docker by default uses Docker Hub to look for images.When docker pull or docker run command are used, it pulls the required image from the registry and when you use docker push, the image is pushed to the registry. Docker Objects When we use docker there are different docker objects that we come across. Let us check them one by one and get a brief overview of some of them Docker Images : Docker image is a read only template with different commands

4. for creating a container. We can also write down our own custom images and publish it over Docker Hub. Docker Containers It is the runnable instance of an docker image. Anyone can create,run, start, stop or delete a container using API or CLI commands. Container can be connected to one or more virtual private networks. Docker Services It allows us to scale containers across multiple docker daemons, which all together works as a swarm cluster with multiple managers or workers. All the members in a swarm is a docker daemon and they communicate with each other using the Docker API. For More Information about Docker & Kubernetes Online Training ClickHere Ph No: +91-9989971070, E-Mail ID: online@visualpath.in