docker-borgbackup-sshd/docker-compose.yml

version: '2.3'

volumes:
  ssh_host_keys:
  repository:
  #additional_repositories:

services:
  sshd:
    build: .
    image: docker.io/fphammerle/borgbackup-sshd
    container_name: borgbackup_sshd
    environment:
      SSH_CLIENT_PUBLIC_KEYS: |
        ssh-rsa ...
        ssh-rsa ...
      SSH_CLIENT_PUBLIC_KEYS_APPEND_ONLY: |
        ssh-rsa ...
        ssh-rsa ...
      #REPO_PATH_foo: /additional-repositories/foo
      #SSH_CLIENT_PUBLIC_KEYS_foo: |
      #  ssh-rsa ...
      #  ssh-rsa ...
      #SSH_CLIENT_PUBLIC_KEYS_APPEND_ONLY_foo: |
      #  ssh-rsa ...
      #  ssh-rsa ...
      #REPO_PATH_bar: /additional-repositories/bar
      #SSH_CLIENT_PUBLIC_KEYS_APPEND_ONLY_bar: |
      #  ssh-rsa ...
      #  ssh-rsa ...
    read_only: true
    volumes:
    - type: volume
      source: ssh_host_keys
      target: /etc/ssh/host_keys
      read_only: false
    - type: volume
      source: repository
      target: /repository
      read_only: false
    #- type: volume
    #  source: additional_repositories
    #  target: /additional-repositories
    #  read_only: false
    - type: tmpfs
      target: /home/borg/.ssh # authorized_keys
      tmpfs:
        # nosuid,nodev,noexec added by default
        mode: '1777'
        size: 16k
    - type: tmpfs
      # > FileNotFoundError: [Errno 2] No usable temporary directory found [...]
      target: /tmp
      tmpfs:
        mode: '1777'
        size: 1M
    ports:
    - '127.0.0.1:2200:2200'
    cap_drop: [ALL]
    security_opt: [no-new-privileges]
    # docker-compose >=2.2,<3
    cpus: 0.8
    mem_limit: 128M

# https://docs.docker.com/compose/compose-file/compose-file-v2/