Atmos Devcontainer

Purpose

Atmos provides native devcontainer management for creating standardized, reproducible development environments. It provides built-in orchestration that integrates with Atmos authentication, toolchains, and project configuration, replacing the need for external orchestration tooling like Geodesic (though Geodesic container images remain fully supported).

Note: The devcontainer feature is currently experimental. By default (settings.experimental: warn), Atmos displays a warning but runs the command. Set settings.experimental: silence in atmos.yaml to suppress the warning, or disable to block experimental commands entirely.

Core Concepts

Devcontainer Configuration

Devcontainers are configured at the top level of atmos.yaml (not under components:). Each named devcontainer defines container settings and a devcontainer spec:

devcontainer:
  default:
    settings:
      runtime: docker           # docker or podman (auto-detected if omitted)
    spec:
      name: "Atmos Default"
      image: "cloudposse/geodesic:latest"
      workspaceFolder: "/workspace"
      workspaceMount: "type=bind,source=${WORKSPACE},target=/workspace"
      mounts:
        - "type=bind,source=${HOME}/.aws,target=/root/.aws,readonly"
      forwardPorts:
        - 8080
      containerEnv:
        ATMOS_BASE_PATH: "/workspace"
      remoteUser: "root"

Supported Spec Features

The following devcontainer spec fields are supported:

Field	Description
name	Display name for the container
image	Container image to use
build.dockerfile	Path to Dockerfile
build.context	Build context directory
build.args	Build arguments
workspaceFolder	Path inside container for workspace
workspaceMount	Mount specification for workspace
mounts	Additional mount points
forwardPorts	Ports to forward to host
portsAttributes	Port binding configuration
runArgs	Extra arguments passed to container runtime
containerEnv	Environment variables set inside container
remoteUser	User to run as inside container

Unsupported fields (features, postCreateCommand, customizations, etc.) are silently ignored with debug-level logging, allowing compatibility with VS Code devcontainer.json files. Use ATMOS_LOGS_LEVEL=Debug to see which fields are being ignored.

Importing from devcontainer.json

Use !include to import existing VS Code devcontainer configurations:

devcontainer:
  vscode:
    settings:
      runtime: docker
    spec: !include .devcontainer/devcontainer.json

Container Naming

Containers follow the naming convention: atmos-devcontainer.{name}.{instance}

• Dot (.) separator avoids parsing ambiguity with hyphenated names
• Default instance name is default
• Multiple instances of the same devcontainer can run simultaneously

Container Labels

All Atmos devcontainers are labeled for management:

tools.atmos.type=devcontainer
tools.atmos.devcontainer.name={name}
tools.atmos.devcontainer.instance={instance}
tools.atmos.workspace={workspace-path}
tools.atmos.created={timestamp}

Runtime Auto-Detection

Atmos automatically detects the available container runtime:

1. Docker (checked first)
2. Podman (fallback)

Override with settings.runtime in the devcontainer configuration.

Key Commands

Lifecycle Management

atmos devcontainer start default           # Start (create if needed)
atmos devcontainer stop default            # Stop running container
atmos devcontainer remove default          # Remove container and data
atmos devcontainer rebuild default         # Destroy and recreate from scratch

Interactive Access

atmos devcontainer shell                   # Start + attach in one command
atmos devcontainer shell default           # Named devcontainer
atmos devcontainer attach default          # Attach to running container

Command Execution

atmos devcontainer exec default -- terraform plan
atmos devcontainer exec default -- aws sts get-caller-identity

Information

atmos devcontainer list                    # List all configured devcontainers
atmos devcontainer config default          # Display resolved configuration
atmos devcontainer logs default            # Show container logs

Instance Management

Multiple instances of the same devcontainer can run simultaneously:

atmos devcontainer start default --instance alice
atmos devcontainer start default --instance bob
atmos devcontainer list                    # Shows both instances
atmos devcontainer attach default --instance alice

Authentication Integration

Devcontainers integrate with the Atmos identity system for credential injection:

atmos devcontainer shell default --identity prod-admin
atmos devcontainer exec default --identity dev -- terraform plan

When --identity is specified, Atmos resolves the identity credentials and passes them to the container environment.

Common Patterns

Standard Development Environment

devcontainer:
  default:
    spec:
      name: "Infrastructure Dev"
      image: "cloudposse/geodesic:latest"
      workspaceFolder: "/workspace"
      workspaceMount: "type=bind,source=${WORKSPACE},target=/workspace"
      mounts:
        - "type=bind,source=${HOME}/.aws,target=/root/.aws,readonly"
        - "type=bind,source=${HOME}/.ssh,target=/root/.ssh,readonly"
      containerEnv:
        ATMOS_BASE_PATH: "/workspace"
        AWS_PROFILE: "default"
      remoteUser: "root"

Multiple Environments

devcontainer:
  dev:
    spec:
      name: "Dev Environment"
      image: "cloudposse/geodesic:latest"
      containerEnv:
        ATMOS_BASE_PATH: "/workspace"
        ENVIRONMENT: "dev"

  prod:
    spec:
      name: "Prod Environment"
      image: "cloudposse/geodesic:latest"
      containerEnv:
        ATMOS_BASE_PATH: "/workspace"
        ENVIRONMENT: "prod"

Custom Dockerfile

devcontainer:
  custom:
    spec:
      name: "Custom Dev"
      build:
        dockerfile: .devcontainer/Dockerfile
        context: .
        args:
          TERRAFORM_VERSION: "1.9.8"
      workspaceFolder: "/workspace"
      workspaceMount: "type=bind,source=${WORKSPACE},target=/workspace"