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I've compiled a list of Dockerfile commands and parameters to look at.

Popularity：323 ℃/2024-09-11 20:05:23

Dockerfile Main commands and parameters:

directives Main parameters corresponds English -ity, -ism, -ization usage example
FROM <image>[:<tag>] [AS <name>] Specify the base image FROM ubuntu:24.04 AS base
RUN <command> or ["executable", "param1", "param2"] Execute commands, usually used to install packages RUN apt-get update && apt-get install -y python3
CMD <command> or ["executable", "param1", "param2"] Specifies the command to be executed when the container starts CMD ["python3", ""]
LABEL <key>=<value> Adding metadata to a mirror LABEL version="1.0" description="This is my app"
EXPOSE <port>[/<protocol>] Declare the port on which the container listens when running EXPOSE 80/tcp
ENV <key>=<value> Setting environment variables ENV NODE_ENV production
ADD <src>... <dest> Copying files, URL support and automatic decompression ADD / /usr/src/things/
COPY [--chown=<user>:<group>] <src>... <dest> Copying a file or directory COPY --chown=user:group files* /data/
ENTRYPOINT ["executable", "param1", "param2"] Sets the entry point to the container, usually used in conjunction with CMD ENTRYPOINT ["nginx", "-g", "daemon off;"]
VOLUME ["/data"] Create mount points for persistent data VOLUME ["/var/log/"]
USER <user>[:<group>] Specify the username or UID to use when running the container USER www-data
WORKDIR /path/to/workdir Setting up the working directory WORKDIR /app
ARG <name>[=<default value>] Define build parameters that can be passed at build time ARG VERSION=latest
ONBUILD INSTRUCTION Add a trigger to the image to execute a specific command ONBUILD RUN /usr/local/bin/python-build --dir /app/src
STOPSIGNAL signal Setting the system call signal to stop the container STOPSIGNAL SIGTERM
HEALTHCHECK [OPTIONS] CMD command Defining container health checks `HEALTHCHECK --interval=5m --timeout=3s CMD curl -f http://localhost/
SHELL ["executable", "parameters"] Override the default shell SHELL ["/bin/bash", "-c"]
COPY --from Copying files from a multi-stage build COPY --from=builder /app /app
RUN --mount Mounting directories or caches at build time RUN --mount=type=cache,target=/root/.cache pip install -r

Additional parameters and options:

  1. COPY and ADD commands:

    • --chown=\<user\>:\<group\>
    • --chmod=\<permissions>
    • --from=\<name|index>

  2. RUN command:

    • --mount=type=\<type>,target=\<path>,source=\<source>
    • --network=\<network>
    • --security=\<security-opt>

  3. HEALTHCHECK command option:

    • --interval=DURATION (Default: 30s)
    • --timeout=DURATION (Default: 30s)
    • --start-period=DURATION (Default: 0s)
    • --retries=N (Default: 3)

  4. ARG Directive:

    • Can be used before the FROM directive, affecting the selection of the base image

  5. Multi-stage construction is relevant:

    • FROM \<image\> AS \<stage>
    • COPY --from=\<stage\> \<src\> \<dest>

Sample Dockerfile:

> #### Note: This document is for reference only, do not use it directly!


# Syntax version declaration
# syntax=docker/dockerfile:1

# Define build parameters
ARG BASE_IMAGE=ubuntu:24.04

# Specify the base image
FROM ${BASE_IMAGE} AS base

# Set the maintainer information (deprecated, use LABEL instead)
MAINTAINER John Doe <@>

# LABEL to add metadata
# Instead of MAINTAINER
LABEL = "John Doe <john@>"
LABEL version="1.0" description="This is an example Dockerfile"

# Setting environment variables
ENV APP_HOME=/app \
    NODE_ENV=production

# Set the working directory
WORKDIR ${APP_HOME}

# Copy files to the image
COPY --chown=node:node . .

# Add remote files to the mirror
ADD / /tmp/

# Run the command
RUN apt-get update && apt-get install -y python3 \
    && apt-get clean \
    && rm -rf /var/lib/apt/lists/*

# Run the command using mount (requires BuildKit support)
RUN --mount=type=cache,target=/root/.cache \
    pip install -r

# Expose ports
EXPOSE 8080

# Create the data volume
VOLUME ["/data"]

# Set the default user
USER node

# Define health check
HEALTHCHECK --interval=5m --timeout=3s \
  CMD curl -f http://localhost:8080/ || exit 1

# Set the command to run when the container starts
ENTRYPOINT ["node"]

# Set the default command
CMD [""]

# Set the stop signal
STOPSIGNAL SIGTERM

# Change the default shell
SHELL ["/bin/bash", "-c"]

# Multi-stage build: new stage
FROM base AS production

# Add a trigger command to the submirror
ONBUILD RUN echo "This is triggered when used as a base image"

# Copy files from previous stage
COPY --from=base ${APP_HOME} ${APP_HOME}

> AI reminder of what to look for when building a Dockerfile:
> - some commands (e.g.HEALTHCHECK and RUN --mount)A newer version of Docker or a specific builder such as BuildKit is required to use it.
> - In practice, you will typically not use all of these directives in a single Dockerfile. You should choose the appropriate directives based on your project needs.
> - The order of the instructions is important, especially for things likeFROM、ARG、ENVsuch instructions, they affect the behavior of subsequent instructions.
> - multi-stage builds (used in this example)FROM ... AS ...) is an advanced technique for optimizing image size and improving security.
> - MAINTAINERcommand has been deprecated and it is recommended to use theLABELto add maintainer information.

Reference.
[1] /reference/dockerfile/
[2] /build/concepts/dockerfile/

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