The LinuxServer.io team brings you another container release featuring:

regular and timely application updates
easy user mappings (PGID, PUID)
custom base image with s6 overlay
weekly base OS updates with common layers across the entire LinuxServer.io ecosystem to minimise space usage, down time and bandwidth
regular security updates

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linuxserver/openssh-server

Openssh-server is a sandboxed environment that allows ssh access without giving keys to the entire server. Giving ssh access via private key often means giving full access to the server. This container creates a limited and sandboxed environment that others can ssh into. The users only have access to the folders mapped and the processes running inside this container.

Supported Architectures

We utilise the docker manifest for multi-platform awareness. More information is available from docker here and our announcement here.

Simply pulling lscr.io/linuxserver/openssh-server:latest should retrieve the correct image for your arch, but you can also pull specific arch images via tags.

The architectures supported by this image are:

Architecture	Available	Tag
x86-64	✅	amd64-<version tag>
arm64	✅	arm64v8-<version tag>
armhf	✅	arm32v7-<version tag>

Application Setup

If PUBLIC_KEY or PUBLIC_KEY_FILE, or PUBLIC_KEY_DIR variables are set, the specified keys will automatically be added to authorized_keys. If not, the keys can manually be added to /config/.ssh/authorized_keys and the container should be restarted. Removing PUBLIC_KEY or PUBLIC_KEY_FILE variables from docker run environment variables will not remove the keys from authorized_keys. PUBLIC_KEY_FILE and PUBLIC_KEY_DIR can be used with docker secrets.

We provide the ability to set and allow password based access via the PASSWORD_ACCESS and USER_PASSWORD variables, though we as an organization discourage using password auth for public facing ssh endpoints.

Connect to server via ssh -i /path/to/private/key -p PORT USER_NAME@SERVERIP

Setting SUDO_ACCESS to true by itself will allow passwordless sudo. USER_PASSWORD and USER_PASSWORD_FILE allow setting an optional sudo password.

The users only have access to the folders mapped and the processes running inside this container. Add any volume mappings you like for the users to have access to. To install packages or services for users to access, use the LinuxServer container customization methods described in this blog article.

Sample use case is when a server admin would like to have automated incoming backups from a remote server to the local server, but they might not want all the other admins of the remote server to have full access to the local server. This container can be set up with a mounted folder for incoming backups, and rsync installed via LinuxServer container customization described above, so that the incoming backups can proceed, but remote server and its admins' access would be limited to the backup folder.

It is also possible to run multiple copies of this container with different ports mapped, different folders mounted and access to different private keys for compartmentalized access.

TIPS

You can volume map your own text file to /etc/motd to override the message displayed upon connection. You can optionally set the docker argument hostname

Key Generation

This container has a helper script to generate an ssh private/public key. In order to generate a key please run:

docker run --rm -it --entrypoint /keygen.sh linuxserver/openssh-server

Then simply follow the prompts. The keys generated by this script are only displayed on your console output, so make sure to save them somewhere after generation.

Usage

Here are some example snippets to help you get started creating a container.

docker-compose (recommended, click here for more info)

---
version: "2.1"
services:
  openssh-server:
    image: lscr.io/linuxserver/openssh-server:latest
    container_name: openssh-server
    hostname: openssh-server #optional
    environment:
      - PUID=1000
      - PGID=1000
      - TZ=Europe/London
      - PUBLIC_KEY=yourpublickey #optional
      - PUBLIC_KEY_FILE=/path/to/file #optional
      - PUBLIC_KEY_DIR=/path/to/directory/containing/_only_/pubkeys #optional
      - PUBLIC_KEY_URL=https://github.com/username.keys #optional
      - SUDO_ACCESS=false #optional
      - PASSWORD_ACCESS=false #optional
      - USER_PASSWORD=password #optional
      - USER_PASSWORD_FILE=/path/to/file #optional
      - USER_NAME=linuxserver.io #optional
    volumes:
      - /path/to/appdata/config:/config
    ports:
      - 2222:2222
    restart: unless-stopped

docker cli (click here for more info)

docker run -d \
  --name=openssh-server \
  --hostname=openssh-server `#optional` \
  -e PUID=1000 \
  -e PGID=1000 \
  -e TZ=Europe/London \
  -e PUBLIC_KEY=yourpublickey `#optional` \
  -e PUBLIC_KEY_FILE=/path/to/file `#optional` \
  -e PUBLIC_KEY_DIR=/path/to/directory/containing/_only_/pubkeys `#optional` \
  -e PUBLIC_KEY_URL=https://github.com/username.keys `#optional` \
  -e SUDO_ACCESS=false `#optional` \
  -e PASSWORD_ACCESS=false `#optional` \
  -e USER_PASSWORD=password `#optional` \
  -e USER_PASSWORD_FILE=/path/to/file `#optional` \
  -e USER_NAME=linuxserver.io `#optional` \
  -p 2222:2222 \
  -v /path/to/appdata/config:/config \
  --restart unless-stopped \
  lscr.io/linuxserver/openssh-server:latest

Parameters

Container images are configured using parameters passed at runtime (such as those above). These parameters are separated by a colon and indicate <external>:<internal> respectively. For example, -p 8080:80 would expose port 80 from inside the container to be accessible from the host's IP on port 8080 outside the container.

Parameter	Function
`--hostname=`	Optionally the hostname can be defined.
`-p 2222`	ssh port
`-e PUID=1000`	for UserID - see below for explanation
`-e PGID=1000`	for GroupID - see below for explanation
`-e TZ=Europe/London`	Specify a timezone to use EG Europe/London
`-e PUBLIC_KEY=yourpublickey`	Optional ssh public key, which will automatically be added to authorized_keys.
`-e PUBLIC_KEY_FILE=/path/to/file`	Optionally specify a file containing the public key (works with docker secrets).
`-e PUBLIC_KEY_DIR=/path/to/directory/containing/_only_/pubkeys`	Optionally specify a directory containing the public keys (works with docker secrets).
`-e PUBLIC_KEY_URL=https://github.com/username.keys`	Optionally specify a URL containing the public key.
`-e SUDO_ACCESS=false`	Set to `true` to allow `linuxserver.io`, the ssh user, sudo access. Without `USER_PASSWORD` set, this will allow passwordless sudo access.
`-e PASSWORD_ACCESS=false`	Set to `true` to allow user/password ssh access. You will want to set `USER_PASSWORD` or `USER_PASSWORD_FILE` as well.
`-e USER_PASSWORD=password`	Optionally set a sudo password for `linuxserver.io`, the ssh user. If this or `USER_PASSWORD_FILE` are not set but `SUDO_ACCESS` is set to true, the user will have passwordless sudo access.
`-e USER_PASSWORD_FILE=/path/to/file`	Optionally specify a file that contains the password. This setting supersedes the `USER_PASSWORD` option (works with docker secrets).
`-e USER_NAME=linuxserver.io`	Optionally specify a user name (Default:`linuxserver.io`)
`-v /config`	Contains all relevant configuration files.

Environment variables from files (Docker secrets)

You can set any environment variable from a file by using a special prepend FILE__.

As an example:

-e FILE__PASSWORD=/run/secrets/mysecretpassword

Will set the environment variable PASSWORD based on the contents of the /run/secrets/mysecretpassword file.

Umask for running applications

For all of our images we provide the ability to override the default umask settings for services started within the containers using the optional -e UMASK=022 setting. Keep in mind umask is not chmod it subtracts from permissions based on it's value it does not add. Please read up here before asking for support.

User / Group Identifiers

When using volumes (-v flags) permissions issues can arise between the host OS and the container, we avoid this issue by allowing you to specify the user PUID and group PGID.

Ensure any volume directories on the host are owned by the same user you specify and any permissions issues will vanish like magic.

In this instance PUID=1000 and PGID=1000, to find yours use id user as below:

  $ id username
    uid=1000(dockeruser) gid=1000(dockergroup) groups=1000(dockergroup)

Docker Mods

We publish various Docker Mods to enable additional functionality within the containers. The list of Mods available for this image (if any) as well as universal mods that can be applied to any one of our images can be accessed via the dynamic badges above.

Support Info

Shell access whilst the container is running: docker exec -it openssh-server /bin/bash
To monitor the logs of the container in realtime: docker logs -f openssh-server
container version number
- docker inspect -f '{{ index .Config.Labels "build_version" }}' openssh-server
image version number
- docker inspect -f '{{ index .Config.Labels "build_version" }}' lscr.io/linuxserver/openssh-server:latest

Updating Info

Most of our images are static, versioned, and require an image update and container recreation to update the app inside. With some exceptions (ie. nextcloud, plex), we do not recommend or support updating apps inside the container. Please consult the Application Setup section above to see if it is recommended for the image.

Below are the instructions for updating containers:

Via Docker Compose

Update all images: docker-compose pull
- or update a single image: docker-compose pull openssh-server
Let compose update all containers as necessary: docker-compose up -d
- or update a single container: docker-compose up -d openssh-server
You can also remove the old dangling images: docker image prune

Via Docker Run

Update the image: docker pull lscr.io/linuxserver/openssh-server:latest
Stop the running container: docker stop openssh-server
Delete the container: docker rm openssh-server
Recreate a new container with the same docker run parameters as instructed above (if mapped correctly to a host folder, your /config folder and settings will be preserved)
You can also remove the old dangling images: docker image prune

Via Watchtower auto-updater (only use if you don't remember the original parameters)

Pull the latest image at its tag and replace it with the same env variables in one run:

docker run --rm \
-v /var/run/docker.sock:/var/run/docker.sock \
containrrr/watchtower \
--run-once openssh-server

You can also remove the old dangling images: docker image prune

Note: We do not endorse the use of Watchtower as a solution to automated updates of existing Docker containers. In fact we generally discourage automated updates. However, this is a useful tool for one-time manual updates of containers where you have forgotten the original parameters. In the long term, we highly recommend using Docker Compose.

Image Update Notifications - Diun (Docker Image Update Notifier)

We recommend Diun for update notifications. Other tools that automatically update containers unattended are not recommended or supported.

Building locally

If you want to make local modifications to these images for development purposes or just to customize the logic:

git clone https://github.com/linuxserver/docker-openssh-server.git
cd docker-openssh-server
docker build \
  --no-cache \
  --pull \
  -t lscr.io/linuxserver/openssh-server:latest .

The ARM variants can be built on x86_64 hardware using multiarch/qemu-user-static

docker run --rm --privileged multiarch/qemu-user-static:register --reset

Once registered you can define the dockerfile to use with -f Dockerfile.aarch64.

Versions

18.10.22: - Fix wrong behavior of password/passwordless sudo
11.10.22: - Rebase to Alpine 3.16, migrate to s6v3.
15.09.22: - add netcat-openbsd with support for proxies.
18.07.22: - Fix service perms to comply with upgrade to s6 v3.
16.04.22: - Rebase to alpine 3.15.
16.11.21: - Add PUBLIC_KEY_URL option
28.06.21: - Rebasing to alpine 3.14. Add support for PAM.
10.02.21: - Rebasing to alpine 3.13. Add openssh-client for scp.
21.10.20: - Implement s6-log for openssh, which adds local timestamps to logs and can be used with a log parser like fail2ban.
20.10.20: - Set umask for sftp.
01.06.20: - Rebasing to alpine 3.12.
18.01.20: - Add key generation script.
13.01.20: - Add openssh-sftp-server.
19.12.19: - Rebasing to alpine 3.11.
17.10.19: - Initial Release.

dheater/docker-openssh-server