Ssh – command not found when using docker container

I use a docker container in my gitlab ci to login into a server via ssh. When I login into the server via my computer is it possible to run php70 or /usr/bin/php71 without errors. Also there is the typical user@pc:path on the left side.

When I use the ssh client in the docker container and I'm logged in into the server there is only "$" and no user@pc:path and commands like php70 or /usr/bin/php71 are not found. My first idea was ,that I use a diferent shell but echo $SHELL is at both /bin/bash. My gitlab-ci.yml code is this:

image: ruby:2.1
  stage: on_server
  environment: production
  before_script:
    # install ssh-agent
    - 'which ssh-agent || ( apt-get update -y && apt-get install openssh-client -y )'

    # run ssh-agent
    - eval $(ssh-agent -s)

    # add ssh key stored in SSH_PRIVATE_KEY variable to the agent store
    - ssh-add <(echo "$SSH_KEY_PRIVATE")

    # disable host key checking (NOTE: makes you susceptible to man-in-the-middle attacks)
    # WARNING: use only in docker container, if you use it with shell you will overwrite your user's ssh config
    - mkdir -p ~/.ssh
    - echo -e "Host *\n\tStrictHostKeyChecking no\n\n" > ~/.ssh/config

  script:
    - ssh $SSH_USER_PRODUCTION@$FTP_HOST_PRODUCTION "bash -l"
    - bash
    - echo $SHELL
    - echo $PATH
    - SYMFONY_ENV=prod php71 composer.phar install --no-dev --optimize-autoloader --ignore-platform-reqs
    - SYMFONY_ENV=prod php71 app/console doctrine:migrations:migrate
    - SYMFONY_ENV=prod php71 app/console cache:clear --env=prod

Does anybody know where this behavoir came from?