in order to work with ssh cloning, one has to manually install openssh-client to the docker image, looks like that
Correct, you have to have SSH inside the container so that git can use it.
You can always install with the following setup inside your agent's clearml.conf:
extra_docker_shell_script: ["apt-get install -y openssh-client", ]
I don't think so. it is solved by installing openssh-client to the docker image or by adding deploy token to the cloning url in web ui
You can also have the token (token==password) configured as the defauylt user/pass in your agent's clearml.conf