redis education docker docker_redis_image

Docker Redis Image

Docker Redis Image

Dockerfile

• CMD: It will be specified at run time, so it was not used here.
• EXPOSE: It will be specified at run time, and the ports to use will be set in the redis.conf file, so it was not used here.

Build a Redis image

• The last period (.) is the location of the Dockerfile.

Run a Redis image

Connect with a shell

Connect with redis-cli

Dockerfile instructions

• FROM: Specifies the base image.
  FROM image[:tag] [AS name]
📄 Dockerfile
FROM centos:7.0.1406
• MAINTAINER: Provides contact information for the person who created the image.
  It can be replaced by Label.
  MAINTAINER name
📄 Dockerfile
MAINTAINER redisgate <redisgate@gmail.com>
• LABEL: Provides a label (description).
  LABEL key=value
📄 Dockerfile
LABEL name=redis LABEL varsion=5.0.3 LABEL maintainer=redisgate@gmail.com
• USER: Specifies the user. The default is root.
  USER root
• ENV: Specifies environment variables. It helps avoid repetitive work and prevent errors.
📄 Dockerfile
ENV WDIR /redis   <- specify RUN mkdir $WDIR   <- use WORKDIR $WDIR   <- use
• VOLUME: Specifies a volume. You can mount a host directory onto this volume.
📄 Dockerfile
VOLUME $WDIR VOLUME /redis

The following are characteristics of volumes.
• A volume is a directory separated from the container's root file system.
• Volumes are managed directly by the Docker daemon and can be shared between containers.
• A volume can be used when mounting a host directory into a container.
• When a running container is updated into an image, the volume is not included in the update.
• Because a volume is a file system separate from the container, it is not included in the layers that make up the image. Therefore, reading from or writing to a volume is done directly without going through layers.
• If multiple containers use one volume, that volume is kept until all of those containers have stopped.
• WORKDIR: Specifies the working directory. RUN and CMD instructions run in the working directory.
📄 Dockerfile
WORKDIR $WDIR WORKDIR /redis
• ADD: Copies host files into the image.
📄 Dockerfile
ADD redis-5.0.3/redis-server /usr/local/bin/ ADD redis-5.0.3/redis-cli /usr/local/bin/
• COPY: Copies host files into the image. It is more limited than ADD.
• EXPOSE: Specifies the ports to use from outside the container.
  It is used for links between containers, and you must connect it to a host port with RUN -p host_port:container_port.
📄 Dockerfile
EXPOSE 6001 EXPOSE 6002 6003
• RUN: Runs a command.
📄 Dockerfile
RUN ln -s /usr/local/bin/redis-server /usr/local/bin/redis-sentinel RUN mkdir $WDIR
• CMD: A command that starts the process you want to run inside the container.
📄 Dockerfile
CMD redis-server redis.conf
• ENTRYPOINT: Similar to CMD, but it is not overwritten by the RUN command.
  ENTRYPOINT file or sh arg1 arg2
📄 Dockerfile
ENTRYPOINT /code/entrypoint.sh ENTRYPOINT redis-server redis.conf
• ONBUILD
• STOPSIGNAL
• HEALTHCHECK
📄 Dockerfile
HEALTHCHECK --interval=5s --timeout=3s CMD curl --fail http://localhost:8091/pools || exit 1
• SHELL