SSHD

Minimal Alpine Linux Docker image with sshd exposed and rsync installed.

Mount your .ssh credentials (RSA public keys) at /root/.ssh/ in order to access the container via root and set SSH_ENABLE_ROOT=true or mount each user's key in /etc/authorized_keys/<username> and set SSH_USERS config to create user accounts (see below).

Optionally mount a custom sshd config at /etc/ssh/.

Environment Options

• SSH_USERS list of user accounts and uids/gids to create. eg SSH_USERS=www:48:48,admin:1000:1000
• SSH_ENABLE_ROOT if "true" unlock the root account
• MOTD change the login message
• SFTP_MODE if "true" sshd will only accept sftp connections
• SFTP_CHROOT if in sftp only mode sftp will be chrooted to this directory. Default "/data"

SSH Host Keys

SSH uses host keys to identity the server you are connecting to. To avoid receiving security warning the containers host keys should be mounted on an external volume.

By default this image will create new host keys in /etc/ssh/keys which should be mounted on an external volume. If you are using existing keys and they are mounted in /etc/ssh this image will use the default host key location making this image compatible with existing setups.

If you wish to configure SSH entirely with environment variables it is suggested that you externally mount /etc/ssh/keys instead of /etc/ssh.

SFTP mode

When in sftp only mode (activated by setting SFTP_MODE=true the container will only accept sftp connections. All sftp actions will be chrooted to the SFTP_CHROOT directory which defaults to "/data".

Please note that all components of the pathname in the ChrootDirectory directive must be root-owned directories that are not writable by any other user or group (see man 5 sshd_config).

Usage Example

docker run -d -p 2222:22 -v /secrets/id_rsa.pub:/root/.ssh/authorized_keys -v /mnt/data/:/data/ -e SSH_ENABLE_ROOT=true docker.io/panubo/sshd

or

docker run -d -p 2222:22 -v $(pwd)/.ssh/id_rsa.pub:/etc/authorized_keys/www -e SSH_USERS="www:48:48" docker.io/panubo/sshd

Status

Production ready and stable.