In Docker, the RUN and CMD instructions serve different purposes, primarily relating to when and how commands are executed within the container lifecycle. RUN Instruction : Purpose : The RUN command is used to build the image. It executes the specified command(s) and commits the result to the image, so the changes become part of the image layers. Execution Time: During the build phase of the Docker image. Use Case : Commonly used for installing software, setting up files, or configuring the environment. RUN apt-get update && apt-get install -y nginx Here, RUN installs nginx in the image. When the image is built, the installed software is included in the image. CMD Instruction : Purpose : The CMD command provides default instructions for the container. It defines what should be executed when a container starts. Execution Time: At container runtime (when the container is launched from the image). Use Case : Typically, used to specify the main application or command to ...
Docker is an advanced OS virtualization software platform that makes it easier to create, deploy, and run applications in a Docker container. Docker is a container management service. The keywords of Docker are build, ship and run anywhere. The whole idea of Docker is for developers to easily develop applications, ship them into containers which can then be deployed anywhere. Docker allows the developers to choose the project-specific deployment environment for each project with a different set of tools and application stacks. Docker provides flexibility and portability to run an application in various locations, whether on-premises or in a public cloud or a private cloud. Features of Docker Docker has the ability to reduce the size of development by providing a smaller footprint of the operating system via containers. With containers, it becomes easier for teams across different units, such as development, QA and Operations to work ...