How docker implements packaging

　

#How does docker implement packaging?

Docker related terms:

　(1). Mirror, container, warehouse

　Docker’s characteristics:

　(1) .Keywords: container, standard, isolation.

Docker deployment practice:

1. Create dockerfile

Pay attention to the assumptions I mentioned: your jar package or war package All have been packaged successfully and docker has been installed successfully.

The content of dockerfile is as follows:

FROM azul/zulu-openjdk:8
VOLUME /home/work/springDemo
ADD springDemo-0.0.1-SNAPSHOT.jar app.jar
RUN bash -c 'touch /app.jar'
ENTRYPOINT ["java","-Djava.security.egd=file:/dev/./urandom","-jar","/app.jar"]

FROM: Which image it is based on

VOLUME: You can mount local folders or folders of other containers into the container

ADD: Copy the file to the path corresponding to the container's file system

RUN: The RUN command will execute any legal command in the current image and submit the execution results. After the command execution is submitted, the next instruction in the Dockerfile will be automatically executed

ENTRYPOINT: The command executed when the container starts, but there can only be one ENTRYPOINT command in a Dockerfile. If there are multiple ones, only the last one will be executed.

Key points: The location of dockerfile and jar package or war package

Note: The newly created Dockerfile file needs to be in the same folder as the jar.

　 2. Generation of Jar package

You may be confused when you see the .jar package in the picture above. How is this package generated? Let's take a look at how this package is generated.

Since I built the project through maven, I also built it through maven. Of course, the premise is still that maven is installed in your environment. Let’s take a look at the screenshots for the specific operation.

After the above operations, the jar package is built.

　 3. Generate image

Shell command description: The key point is that you need to cd to the folder where the Dockerfile and jar package or war package are stored.

Command: sudo docker build -t springbootdemo .

Note: The . after the command must be brought.

I can’t remember the meaning of the -t parameter. You can view the explanation of related functions through sudo docker build --help. springbootdemo is the image name of the build.

The above operations complete the creation of the Docker image. Check whether the image is created successfully, command: sudo docker images , you can see that springbootdemo is the image just created.

4. Start the container

Containers are actually equivalent to mirror carriers.

Screenshot of container startup command:

Startup command: sudo docker run -d -p 8080:8080 springbootdemo

Parameters of -d -p I have also forgotten the meaning, you can check it out. 8080: 8080 is a port mapping. Its specific logic and principles. I suggest you learn Docker and take a closer look. springbootdemo is the image file I mentioned above.

View the currently running containers: sudo docker ps

5. Verification

For verification, please check us Whether the Demo is deployed successfully, if your jar package or war package is the same as mine and is a web program, you can test it through the browser.

Related recommendations: docker tutorial

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