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Docker

CLI Basics​

Use docker start to start one or more stopped containers. Docs

For example, starting 2 containers at the same time:

docker start peopledepot_web_1 peopledepot_db_1

Use docker stop to stop one or more stopped containers.

docker stop peopledepot_web_1 peopledepot_db_1

Use docker container ls lists all the currently running docker containers.

peopledepot % docker container ls
CONTAINER ID   IMAGE                  COMMAND                  CREATED          STATUS          PORTS                    NAMES
0a2a1a617c0c   peopledepot-web        "/usr/src/app/entryp…"   37 minutes ago   Up 37 minutes   0.0.0.0:8000->8000/tcp   peopledepot-web-1
4a1f98f98a54   postgres:13.0-alpine   "docker-entrypoint.s…"   37 minutes ago   Up 37 minutes   5432/tcp                 peopledepot-db-1

If there are no containers running, this also can tell us if Docker is running in the background. 

% docker container ls
CONTAINER ID   IMAGE     COMMAND   CREATED   STATUS    PORTS     NAMES

# no container is running, but Docker the application is running. 

% docker container ls
Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?

# it will explicitly remind us that docker daemon may not be running.

Building multi-platform images​

When you invoke a build, you can set the --platform flag to specify the target platform for the build output, (for example, linux/amd64, linux/arm64, or darwin/amd64). See Building multi-platform images.

Run the docker buildx ls command to list the existing builders:

% docker buildx ls 
NAME/NODE       DRIVER/ENDPOINT STATUS  BUILDKIT PLATFORMS
default *       docker                           
  default       default         running 20.10.22 linux/arm64, linux/amd64, linux/riscv64, linux/ppc64le, linux/s390x, linux/386, linux/arm/v7, linux/arm/v6
desktop-linux   docker                           
  desktop-linux desktop-linux   running 20.10.22 linux/arm64, linux/amd64, linux/riscv64, linux/ppc64le, linux/s390x, linux/386, linux/arm/v7, linux/arm/v6

This displays the default builtin driver, that uses the BuildKit server components built directly into the docker engine, also known as the docker driver. While you can create a new builder to access more complex features like multi-platform builds (see Multi-Platform/Getting Started for more details), you could also just pass the --platform flag into your build command.

Here is an build command without the --platform flag. The -t flag adds a name and optionally a tag in the name:tag format:

docker build -t people-depot-backend-dev .

And we can pass in the --platform flag like so to build a Docker image setting the --platform to be linux/amd64:// m.

docker build --platform=linux/amd64 -t people-depot-backend-dev .

Dockerizing a Node.js web app

To only deploy your backend server, here is a really good sample project:

https://github.com/GoogleCloudPlatform/serverless-expeditions/tree/main/hosting-a-rest-api-with-a-cloud-firestore-backend

Together with a YouTube walk-through @ Google Cloud Tech

References:​

The command docker run -entrypoint="/bin/bash" -i test runs a Docker container using the specified options.

  • docker run is the command to run a new Docker container.
  • -entrypoint="/bin/bash" sets the default command that will be executed when the container starts. In this case, the default command is /bin/bash, which will run the Bash shell inside the container.
  • -i specifies that the container should run in interactive mode, allowing input from the keyboard and output to the terminal.
  • test is the name or ID of the Docker image to use for the container.

In summary, this command runs a Docker container using the test image and starts the Bash shell in interactive mode. The user can then interact with the shell and perform commands inside the container.