Administering dev containers

1. Clone the GitHub repository:

   git clone https://github.com/devcontainers/cli.git

2. Navigate to the cloned directory and install the Dev Container CLI:

   npm install -g @devcontainers/cli

You can create the devcontainer.json file by defining the metadata such as name, description, build or image source, and runtime Visual Studio Code customizations.

Here’s a sample devcontainer.json:

{
  "name": "Java",
  "description": "Java codeserver",
  "build": {
        "Dockerfile": "./Dockerfile"
   },
  "customizations": {
    "vscode": {
      "extensions": [
        "secure-dev-ops.devops-code",
        "redhat.java"
      ]
    }
  }
}

You can also download a sample file here: devcontainer.json

Refer to the Dev Container metadata reference guide to include JSON metadata related to general settings, Docker or Docker Compose-specific options, and tool-specific properties for configuring a devcontainer.js file.

You can add a Dockerfile to define the environment and behavior of your development container by specifying the base image, installing tools, setting environment variables, and configuring the container runtime.

Example Dockerfile:

FROM ubuntu:20.04
ENV DEBIAN_FRONTEND=noninteractive
RUN apt-get update && \
    apt-get install -y sudo curl default-jre git && \
    apt-get clean 	
RUN curl -fsSL https://code-server.dev/install.sh | sh -s -- --version=4.98.0
USER 1001
CMD ["tail", "-f", "/dev/null"]

Key Commands required for the Dockerfile:

• FROM: Set the base image.
• ENV: Set the environment variables.
• RUN: Install dependencies and clean cache to keep the image lean.
• USER: Run the container as a non-root user (1001) for security.
• CMD: Keep the container running by tailing a null file.

  To create or customize a Dockerfile for your development container, refer to the official Dockerfile reference. This guide provides detailed explanations and examples of all supported commands. You can also explore dev container documentation for guidance on integrating your Dockerfile into a .devcontainer setup.

You can download a sample Dockerfile here: Dockerfile

Navigate to the root .devcontainer directory and run the following command to build the dev container image.

devcontainer build --workspace-folder . --image-name devuser/java-container:1.0

This command reads the devcontainer.json file and executes the Dockerfile.

{
                        "name": "Java",
                        "description": "A preconfigured Java development environment with code-server support and Java runtime",
                        "build": {
                        "dockerfile": "./Dockerfile"
                        },
                        "image": "devuser/java-container:1.0",
                        "customizations": {
                        "vscode": {
                        "extensions": [
                        "secure-dev-ops.devops-code",
                        "redhat.java"
                        ]
                        }
                        }
                        }

Login and push:

docker login
docker push devuser/java-container:1.0

After it is pushed, it will be available at: docker.io/devuser/java-container

1. Sign in to IBM® DevOps Loop. Navigate to your teamspace.
2. Go to the Control page. You’ll see a repository named .devopsconfig under your teamspace (e.g., teamspace-java/.devopsconfig).

Inside the .devcontainer folder of the repo, upload devcontainer.json and Dockerfile.

Commit the changes to the main branch.

Ensure both the devcontainer.json and Dockerfile.yml files are correctly uploaded at:

teamspace-java/.devopsconfig/.devcontainer/

1. Go to the Code landing page.
2. Click the teamspace button and switch to your teamspace. Under Dev Containers, you will see a new dev container, along with the default Starter container that is always available for all users.
3. Click Let’s Go to launch the container.

Note: The first-time launch may take a few minutes.

In the code server instance, click the Extensions button to see and verify the extensions you had configured in devcontainer.json file.