Docker container: It is a runnable instance of an image.If you need a newer version, you will need to create a completely new image. Once you have created the image you can’t change it, but you can delete it. Docker images: It is a read-only template with instructions for creating a Docker container.Docker Hub is a public registry that anyone can use, and Docker is configured to look for images on Docker Hub by default. Docker registries: It stores Docker images.Docker client docker: It is a command line tool that allows you to talk to the Docker daemon via the Docker API.It listens for Docker API requests and manages Docker objects such as images, containers, networks, and volumes. Docker daemon dockerd: It is a service that runs on your host operating system.The Docker engine consists of below components: The major Docker components are listed below The Docker daemon listens for Docker API requests and manages Docker objects such as images, containers, networks, and volumes. How Does the Docker Engine Work?ĭocker Engine is a client-server application that builds and runs containers using Docker’s components and services.įor instance, when you run “docker run”, the client sends these commands to “dockerd”. Images are constructed from layered file systems, so they can share common files, disk usage and image downloads are very efficient.ĭocker is designed to run on 64-bit architecture with Linux kernel 3.10 and later. (Docker is completely different from the virtual machine).ĭocker containers run in any system, any infrastructure and any cloud because they are not bonded to any specific infrastructure.Ĭontainers run on the host operating system and share the same kernel, so they start immediately and use RAM more efficiently. This allows the host operating system to run multiple containers and does not require guest operating systems unlike a virtual machine. It uses resource isolation features from the Linux kernel such as cgroups, namespaces and aufs (advanced multi layered unification filesystem). It allows you to run an application with all its dependencies within software containers by sharing the host operating system kernel. It is an open source lightweight virtualization tool that uses OS-level virtualization. Docker is a tool designed to build, deploy, and run applications using containers.

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