$ docker run --rm -it ghcr.io/nextflow-io/training:latest bash
root ➜ / $ apptainer
bash: apptainer: command not found
root ➜ / $ find / -name apptainer

$ docker inspect ghcr.io/nextflow-io/training:latest | grep devcontainer.metadata
 "devcontainer.metadata": [ 
    {'id': 'ghcr.io/devcontainers/features/common-utils:2'}
    {'id': 'ghcr.io/devcontainers/features/git:1', 'customizations': {'vscode': {'settings': 
    {'github.copilot.chat.codeGeneration.instructions': [{'text': 'This dev container includes an up-to-date version of Git, built from source as needed, pre-installed and available on the `PATH`.'}]}}}}
    {'remoteUser': 'vscode'}
>>>>{'id': '../local-features/apptainer'}<<<<
    {'id': '../local-features/init'}
    {'id': '../local-features/tower-agent'}
    {'id': 'ghcr.io/devcontainers/features/docker-outside-of-docker:1', 'securityOpt': ['label=disable'], 'entrypoint': '/usr/local/share/docker-init.sh', 'mounts': [{'source': '/var/run/docker.sock', 'target': '/var/run/docker-host.sock', 'type': 'bind'}], 'customizations': {'vscode': {'extensions': ['ms-azuretools.vscode-docker'], 'settings': 
    {'github.copilot.chat.codeGeneration.instructions': [{'text': 'This dev container includes the Docker CLI (`docker`) pre-installed and available on the `PATH` for running and managing containers using the Docker daemon on the host machine.'}]}}}}
    {'id': 'ghcr.io/devcontainers/features/java:1', 'customizations': {'vscode': {'extensions': ['vscjava.vscode-java-pack'], 'settings': {'java.import.gradle.java.home': '/usr/local/sdkman/candidates/java/current'}}}}
    {'id': 'ghcr.io/rocker-org/devcontainer-features/miniforge:2'}
    {'id': 'ghcr.io/va-h/devcontainers-features/uv'}
    {'id': '../local-features/conda-channels'}
    {'id': '../local-features/nextflow'}
    {'id': '../local-features/uv-tools'}
    {'onCreateCommand': 'bash .devcontainer/setup.sh', 'customizations': {'vscode': {'extensions': ['nf-core.nf-core-extensionpack'], 'settings': {'python.defaultInterpreterPath': '/opt/conda/bin/python'}, 'terminal.integrated.defaultProfile.linux': 'bash'}}, 'remoteUser': 'root', 'remoteEnv': {'NXF_HOME': '/workspaces/.nextflow', 'NXF_EDGE': '0', 'NXF_VER': '24.10.4', 'HOST_PROJECT_PATH': '/workspaces/training', 'SHELL': '/bin/bash'}}
 ],

$ docker run --rm -it ghcr.io/nextflow-io/training:latest /bin/bash add-apt-repository -
y ppa:apptainer/ppa
/bin/bash: add-apt-repository: No such file or directory

#!/usr/bin/env bash

# Install Apptainer (Singularity)

apt-get update --quiet

# installs add-apt-repository
apt install --reinstall -y software-properties-common

add-apt-repository -y ppa:apptainer/ppa

apt install -y apptainer

apt-get clean
rm -rf /var/lib/apt/lists/*