Dockerfile RUN

Definition:

• Execute any commands to create a new layer on top of the current image

• # Shell form:
  RUN [OPTIONS] <command> ...
  # Exec form:
  RUN [OPTIONS] [ "<command>", ... ]

  • Options:
    • —mount
    • —network
    • —security

• Shell form is most commonly used, and lets you break up longer instructions into multiple lines, either using newline escapes, or with heredocs:

    ```dockerfile
    RUN <<EOF
    apt-get update
    apt-get install -y curl
    EOF
    ```
  

Cache invalidation:

• Invalidate the layer created by RUN instruction so next time it will be ran again

RUN —mount

• Create filesystem mounts that the build can access. This can be used to:
  • Create bind mount to the host filesystem or other build stages
  • Access build secrets or ssh-agent sockets
  • Use a persistent package management cache to speed up your build
• RUN --mount=[type=<TYPE>][,option=<value>[,option=<value>]...]

RUN —mount=type=bind

• This mount type allows binding files or directories to the build container. A bind mount is read-only by default.

RUN —mount=type=cache

• This mount type allows the build container to cache directories for compilers and package managers.

RUN —mount=type=tmpfs

RUN —mount=type=secret

RUN —mount=type=ssh

RUN —network

• RUN —network=TYPE

RUN —network=default

RUN —network=none

RUN —network=host

RUN —security:

• …