Complementary to docker-compose up -d and docker-compose up --build

command explanation

docker-compose up -d

docker-compose up -dThe command is used to start the service container defined in docker-compose.ymlthe file and run in the background as a daemon process.
The specific explanation is as follows:

• docker-compose: is a tool for defining and running multiple container applications.
• up: Used to create and start a container.
• -dOr --detach: Indicates running the container as a daemon process, that is, running in the background without blocking the terminal.
• docker-compose.yml: is a file in YAML format, which is used to define the service configuration of multiple containers, including container mirroring, port mapping, environment variables, data volumes, etc.
  When you execute docker-compose up -dthe command, the file docker-composeis parsed docker-compose.ymland a container is created and started based on the service configuration defined in the file. These containers will run in the background, and you can continue to use the terminal for other operations without being blocked by the container process.
  A container started by docker-compose up -da command continues to run in the background until it is explicitly stopped or docker-compose downa command is used to stop the container.

docker-compose up --build

docker-compose up --buildcommand to rebuild and start the service container.

The specific explanation is as follows:

• docker-compose: is a tool for defining and running multiple container applications.
• up: Used to create and start a container.
• --build: Indicates rebuilding the image of the container.

When you execute docker-compose up --buildthe command, the file docker-composeis parsed docker-compose.ymland the container's image is rebuilt based on the service configuration defined in the file. This means that it will re-execute the building process of the container image, including steps such as downloading dependencies, installing software, and configuring the environment.

• Rebuilding the container's image ensures that the container's code, configuration, etc. are up to date so that the latest version is used when the container is started. This is useful for application updates, configuration changes, or updates to dependencies.

• Once the container image has been rebuilt, docker-composethe new image is used to create and start the container. These containers will run in the background, and you can continue to use the terminal for other operations without being blocked by the container process.

• Be aware that docker-compose up --buildthe command can be time consuming, especially when building the container for the first time or when the container configuration changes. Therefore, it is recommended to use this command when the container needs to be rebuilt. If you just need to start an existing container, you can use docker-compose up -dthe command to quickly start the container.

The difference between the two startup methods

• docker-compose up -dThe command is used to start the existing service container, if the service container does not exist, it will be created automatically. -dThe parameter indicates to run the container as a daemon process.
• docker-compose up --buildcommand to rebuild the service container. If the service container already exists, the command will first stop and remove the existing container, then rebuild and start the container. If the service container does not exist, the container will be built and started directly.
• In summary, docker-compose up -dit is used to start the existing service container, and docker-compose up --buildit is used to rebuild and start the service container.

speed comparison

• docker-compose up -dCommand execution is docker-compose up --buildmuch faster than commands.
• docker-compose up -dThe command only starts the existing service container, and does not need to rebuild the container, so the execution speed is faster.
• docker-compose up --buildThe command needs to rebuild the service container, which will execute the construction process of the container image, which may be time-consuming, especially when the container is built for the first time or the container configuration changes.
• Therefore, if you just need to start an existing service container, you can use docker-compose up -dthe command to quickly start the container. If you need to rebuild the container, you can use docker-compose up --buildthe command.

Question Discussion

1. If I stop and delete the running container and use docker-compose up -d to deploy, will the docker-compose.yml file and the custom dockercompose file included will be re-executed?
   answer:

• If you stop and delete a running container, then docker-compose up -dredeploy with the command, docker-compose.ymlthe file and any custom docker-composefiles it contains will be re-executed.
• docker-composeThe container will docker-compose.ymlbe recreated and started according to the service and container configuration information defined in the file. If there is a custom docker-composefile, it will also be loaded and executed.
• This means that if you make changes to docker-compose.ymlyour files or custom files, those changes will be applied when you redeploy. docker-composeAt the same time, if the previous containers were stopped and deleted, docker-composethey will be recreated and restarted according to the configuration information.