ghcr.io/coolcow/autossh

A minimal Alpine-based Docker image for autossh.

The image runs autossh as non-root via reusable scripts from coolcow/entrypoints and supports injecting SSH material through /install.

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Usage

Quick Start

docker run --rm ghcr.io/coolcow/autossh --help

Provide SSH Config/Keys

Mount a directory with SSH files (for example config, id_rsa, known_hosts) to /install. Files are copied to ${AUTOSSH_HOME}/.ssh before autossh starts.

docker run --rm \
	-e AUTOSSH_UID=$(id -u) \
	-e AUTOSSH_GID=$(id -g) \
	-v /path/to/autossh-home:/home/autossh \
	-v /path/to/ssh-files:/install:ro \
	ghcr.io/coolcow/autossh \
	-M 0 -N user@example.org

Runtime Environment Variables

Variable	Default	Target	Description
AUTOSSH_UID	1000	TARGET_UID	User ID to run the process as.
AUTOSSH_GID	1000	TARGET_GID	Group ID to run the process as.
AUTOSSH_REMAP_IDS	1	TARGET_REMAP_IDS	Set to 0 to disable remapping conflicting UID/GID entries.
AUTOSSH_USER	autossh	TARGET_USER	Runtime user name inside the container.
AUTOSSH_GROUP	autossh	TARGET_GROUP	Runtime group name inside the container.
AUTOSSH_HOME	/home/autossh	TARGET_HOME	Home directory used by autossh and as default workdir.
AUTOSSH_SHELL	/bin/sh	TARGET_SHELL	Login shell for the runtime user.

Target shows the corresponding variable used by coolcow/entrypoints.

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Configuration

Build-Time Arguments

Customize the image at build time with docker build --build-arg <KEY>=<VALUE>.

Argument	Default	Description
ALPINE_VERSION	3.23.3	Version of the Alpine base image.
ENTRYPOINTS_VERSION	2.2.0	Version of the coolcow/entrypoints image used for scripts.

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Migration Notes

Runtime user/group environment variables were renamed to image-specific AUTOSSH_* names.

• PUID → AUTOSSH_UID
• PGID → AUTOSSH_GID
• ENTRYPOINT_USER → AUTOSSH_USER
• ENTRYPOINT_GROUP → AUTOSSH_GROUP
• ENTRYPOINT_HOME → AUTOSSH_HOME

Update your docker run / docker-compose environment configuration accordingly when upgrading from older tags.

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Local Testing

Run the built-in smoke tests locally.

1. docker build -t ghcr.io/coolcow/autossh:local-test-build -f build/Dockerfile build
2. docker build --build-arg APP_IMAGE=ghcr.io/coolcow/autossh:local-test-build -f build/Dockerfile.test build

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References

• autossh Homepage
• docker-entrypoints

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License

MIT. See LICENSE.txt for details.