sample from dsag.sh

write_key() {
        mkdir -p "${JENKINS_AGENT_HOME}/.ssh"
        echo "$1" > "${JENKINS_AGENT_HOME}/.ssh/authorized_keys"
        chown -Rf jenkins:jenkins "${JENKINS_AGENT_HOME}/.ssh"
        chmod 0700 -R "${JENKINS_AGENT_HOME}/.ssh"
}

if [[ $JENKINS_SLAVE_SSH_PUBKEY == ssh-* ]]; then
  write_key "${JENKINS_SLAVE_SSH_PUBKEY}"
fi
if [[ $# -gt 0 ]]; then
  if [[ $1 == ssh-* ]]; then
    write_key "$1"
    shift 1
  else
    exec "$@"
  fi
fi


# ensure variables passed to docker container are also exposed to ssh sessions
env | grep _ >> /etc/environment

ssh-keygen -A
exec /usr/sbin/sshd -D -e "${@}"