yitzikc/centos-sshd repository overview

⁠centos-sshd

Simple CentOS docker image with SSH access

Note: This project is a fork of tutum/centos⁠.= That project has been deprecated by its publishers and is no longer maintained.

Currently, its scope is more limited. Only CentOS 7 is tested and known to work. However, the code for building the latest CentOS has been retained.

It's possible to run systemd inside the container by launching it with appropriate mounts, see Running centos-sshd below. The container will detect automatically if the prerequisites for launching systemd are met. If not it will fall back to launching sshd directly.

⁠Availability

A Docker image for CentOS 7 built from this repository is available on Docker hub⁠, as yitzikc/centos-sshd:centos7

You can adapt the examples below to use it directly, by using the image name yitzikc/centos-sshd:centos7 instead of centos-sshd:centos7.

⁠Usage

To create the image centos-sshd with one tag per CentOS release, execute the following commands on the repository folder:

docker build -t centos:centos7 centos7

The code for building the latest release of CentOS (currently 8) has been retained, but is it likely to encounter errors. To run it:

docker build -t centos:latest .

⁠Running centos-sshd

Run a container from the image you created earlier binding it to port 2222 in all interfaces:

docker run -d -p 0.0.0.0:2222:22 centos-sshd:centos7

The container can run systemd if it is provided with appropriate mounts. Example command for that:

docker run -d -p 0.0.0.0:2222:22 --tmpfs /run -v /sys/fs/cgroup:/sys/fs/cgroup:ro centos-sshd:centos7

Note, that this can only work on Linux hosts and not on Docker Desktop. For a more in-depth explanation of how this works, see this RedHat article⁠.

The first time that you run your container, a random password will be generated for user root. To get the password, check the logs of the container by running:

docker logs <CONTAINER_ID>

You will see an output like the following:

========================================================================
You can now connect to this CentOS container via SSH using:

    ssh -p <port> root@<host>
and enter the root password 'U0iSGVUCr7W3' when prompted

Please remember to change the above password as soon as possible!
========================================================================

In this case, U0iSGVUCr7W3 is the password allocated to the root user.

Done!

⁠Setting a specific password for the root account

If you want to use a preset password instead of a random generated one, you can set the environment variable ROOT_PASS to your specific password when running the container:

docker run -d -p 0.0.0.0:2222:22 -e ROOT_PASS="mypass" centos-sshd:centos7

⁠Adding SSH authorized keys

If you want to use your SSH key to login, you can use the AUTHORIZED_KEYS environment variable. You can add more than one public key separating them by ,:

docker run -d -p 2222:22 -e AUTHORIZED_KEYS="`cat ~/.ssh/id_rsa.pub`" centos-sshd:centos7