Docker is a new craze which is quite popular nowadays. I don’t know much before about it but at my internship, I attended a workshop from (Docker Captain)and from . Dieter Reuter Niclas Mietz bee42 solutions gmbh It was quite fun two days workshop with them and I got to know a lot about it. So let’s get started with Docker. Before getting started with it, you should install Docker on your machine. Take help from here . how to install Docker Okay now, your machine has Docker, so now you may be thinking what Docker really is? Docker is an open platform for building, shipping, and running applications. With Docker, you can manage your infrastructure in the same ways you manage your applications. It’s easy, simple and quite powerful too. Okay as everyone knows we always start with Hello-world In the output, you can see that we are doing many things(what Docker doing). But before that, I want to illustrate something regarding Docker Engine. docker container run hello-world Docker Engine Docker is same like your car, it has an engine which manages everything. It also consists a server known as Docker Daemon(the command) which manages everything for the client(Docker CLI). In between, the API handles the request from the client to the server. The server responds accordingly to the client by managing the images, containers, networks, and volumes. dockerd The Docker daemon listens to API requests and manages Docker objects(images, containers, networks, and volumes). A daemon can also communicate with other daemons to manage Docker services(swarm mode). Docker Daemon: : The Docker client is the way that many Docker users interact with Docker. When you use commands such as the client sends these commands to which carries them out. The command uses the Docker API. The Docker client can communicate with more than one daemon. Docker Client docker run dockerd docker : A Docker stores Docker images. Docker Hub and Docker Cloud are public registries that anyone can use, and Docker is configured to look for images on Docker Hub by default. When you use the or commands, the required images are pulled from your configured registry. When you use the command, your image is pushed to your configured registry. You can upgrade the application by pulling the new version of the image and redeploying the containers. Docker Registries registry docker pull docker run docker push : An is a snapshot of a Docker container. Often, an image is another image, with some additional customization. For example, you may build an image which is based on the image but installs the Nginx web server and your application, as well as the configuration details needed to make your application run. Images are lightweight, small, and fast, when compared to other virtualization technologies. Images image based on ubuntu : A container is a runnable instance of an image. You can create, run, stop, move, or delete a container using the CLI. You can connect a container to one or more networks, attach storage to it, or even create a new image based on its current state. By default, a container is relatively well isolated from other containers and its host machine. You can control how isolated a container’s network, storage, or other underlying subsystems are from other containers or from the host machine. A container is defined by its image as well as any configuration options you provide to it when you create or run it. When a container stops, any changes to its state that are not stored in persistent storage disappears. Containers : It allows you to scale containers across multiple Docker daemons, which all work together as a with multiple and . Each member of a swarm is a Docker daemon, and the daemons all communicate using the Docker API. A service allows you to define the desired state, such as the number of replicas of the service that must be available at any given time. By default, the service is load-balanced across all worker nodes. To the consumer, the Docker service appears to be a single application. Services swarm managers workers After some theory let’s see the output now, Hello from Docker! The docker client contacted to Docker daemon. The Docker daemon pulled the “hello-world” image from the Docker Hub. The Docker daemon created a new container from that image which runs theexecutable that produces the output you are currently reading. The Docker daemon streamed that output to the Docker client, which sent itto your terminal. That’s it, pretty simple and easy. Enjoy the easiness of it.
