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Dockerfile instruction sets

A Dockerfile is a text document used to build Docker images automatically, containing all the commands a user could call on the command line to assemble an image^[400-devops__06-Kubernetes__k8s-paas__01.Docker（已熟悉的可以从第二章开始）.md]. It defines the environment and dependencies required for an application to run, ensuring consistency across different deployment stages^[400-devops__06-Kubernetes__k8s-paas__01.Docker（已熟悉的可以从第二章开始）.md].

Core Instructions

Dockerfiles utilize a specific set of instructions to orchestrate the image creation process^[400-devops__06-Kubernetes__k8s-paas__01.Docker（已熟悉的可以从第二章开始）.md].

Image Foundation and Metadata

  • FROM: Specifies the base image to build upon^[400-devops__06-Kubernetes__k8s-paas__01.Docker（已熟悉的可以从第二章开始）.md].
  • USER: Sets the user name (or UID) to use when running the image^[400-devops__06-Kubernetes__k8s-paas__01.Docker（已熟悉的可以从第二章开始）.md].
  • WORKDIR: Sets the working directory for any RUN, CMD, ENTRYPOINT, COPY, and ADD instructions that follow^[400-devops__06-Kubernetes__k8s-paas__01.Docker（已熟悉的可以从第二章开始）.md].
  • EXPOSE: Informs Docker that the container listens on the specified network ports at runtime^[400-devops__06-Kubernetes__k8s-paas__01.Docker（已熟悉的可以从第二章开始）.md].

Environment and Execution

  • ENV: Sets environment variables^[400-devops__06-Kubernetes__k8s-paas__01.Docker（已熟悉的可以从第二章开始）.md]. These can be used by subsequent instructions or referenced in scripts.
  • RUN: Executes commands in a new layer on top of the current image and commits the results^[400-devops__06-Kubernetes__k8s-paas__01.Docker（已熟悉的可以从第二章开始）.md]. Commonly used for installing packages (e.g., yum install).
  • CMD: Provides the default command to execute when running the container^[400-devops__06-Kubernetes__k8s-paas__01.Docker（已熟悉的可以从第二章开始）.md]. If the container is started without specific arguments, this command runs.
  • ENTRYPOINT: Allows you to configure a container that will run as an executable^[400-devops__06-Kubernetes__k8s-paas__01.Docker（已熟悉的可以从第二章开始）.md].

File Management

  • ADD: Copies files, directories, or remote file URLs from the source location and adds them to the filesystem of the image at the destination path^[400-devops__06-Kubernetes__k8s-paas__01.Docker（已熟悉的可以从第二章开始）.md].
  • [[Docker]]
  • [[Containerization]]

Sources

  • 400-devops__06-Kubernetes__k8s-paas__01.Docker（已熟悉的可以从第二章开始）.md