.. include:: global.rst.inc .. _deployment: Deployment ========== This chapter will give an example how to setup a borg repository server for multiple clients. Machines -------- There are multiple machines used in this chapter and will further be named by their respective fully qualified domain name (fqdn). * The backup server: `backup01.srv.local` * The clients: - John Doe's desktop: `johndoe.clnt.local` - Webserver 01: `web01.srv.local` - Application server 01: `app01.srv.local` User and group -------------- The repository server needs to have only one UNIX user for all the clients. Recommended user and group with additional settings: * User: `backup` * Group: `backup` * Shell: `/bin/bash` (or other capable to run the `borg serve` command) * Home: `/home/backup` Most clients shall initiate a backup from the root user to catch all users, groups and permissions (e.g. when backing up `/home`). Folders ------- The following folder tree layout is suggested on the repository server: * User home directory, /home/backup * Repositories path (storage pool): /home/backup/repos * Clients restricted paths (`/home/backup/repos/`): - johndoe.clnt.local: `/home/backup/repos/johndoe.clnt.local` - web01.srv.local: `/home/backup/repos/web01.srv.local` - app01.srv.local: `/home/backup/repos/app01.srv.local` Restrictions ------------ Borg is instructed to restrict clients into their own paths: ``borg serve --restrict-path /home/backup/repos/`` There is only one ssh key per client allowed. Keys are added for ``johndoe.clnt.local``, ``web01.srv.local`` and ``app01.srv.local``. But they will access the backup under only one UNIX user account as: ``backup@backup01.srv.local``. Every key in ``$HOME/.ssh/authorized_keys`` has a forced command and restrictions applied as shown below: :: command="cd /home/backup/repos/; borg serve --restrict-path /home/backup/repos/", no-port-forwarding,no-X11-forwarding,no-pty .. note:: The text shown above needs to be written on a single line! The options which are added to the key will perform the following: 1. Force command on the ssh key and dont allow any other command to run 2. Change working directory 3. Run ``borg serve`` restricted at the client base path 4. Restrict ssh and do not allow stuff which imposes a security risk Due to the cd command we use, the server automatically changes the current working directory so the client will not need to append the hostname to the remote URI. .. note:: The setup above ignores all client given commandline parameters which are normally appended to the `borg serve` command. Client ------ The client needs to initialize the `pictures` repository like this: borg init backup@backup01.srv.local:pictures Or with the full path (should actually never be used, as only for demonstrational purposes). The server should automatically change the current working directory to the `` folder. borg init backup@backup01.srv.local:/home/backup/repos/johndoe.clnt.local/pictures When `johndoe.clnt.local` tries to access a not restricted path the following error is raised. John Doe tries to backup into the Web 01 path: borg init backup@backup01.srv.local:/home/backup/repos/web01.srv.local/pictures :: ~~~ SNIP ~~~ Remote: borg.remote.PathNotAllowed: /home/backup/repos/web01.srv.local/pictures ~~~ SNIP ~~~ Repository path not allowed Ansible ------- Ansible takes care of all the system-specific commands to add the user, create the folder. Even when the configuration is changed the repository server configuration is satisfied and reproducable. Automate setting up an repository server with the user, group, folders and permissions a Ansible playbook could be used. Keep in mind the playbook uses the Arch Linux `pacman `_ package manager to install and keep borg up-to-date. :: - hosts: backup01.srv.local vars: user: backup group: backup home: /home/backup pool: "{{ home }}/repos" auth_users: - host: johndoe.clnt.local key: "{{ lookup('file', '/path/to/keys/johndoe.clnt.local.pub') }}" - host: web01.clnt.local key: "{{ lookup('file', '/path/to/keys/web01.clnt.local.pub') }}" - host: app01.clnt.local key: "{{ lookup('file', '/path/to/keys/app01.clnt.local.pub') }}" tasks: - pacman: name=borg state=latest update_cache=yes - group: name="{{ group }}" state=present - user: name="{{ user }}" shell=/bin/bash home="{{ home }}" createhome=yes group="{{ group }}" groups= state=present - file: path="{{ home }}" owner="{{ user }}" group="{{ group }}" mode=0700 state=directory - file: path="{{ home }}/.ssh" owner="{{ user }}" group="{{ group }}" mode=0700 state=directory - file: path="{{ pool }}" owner="{{ user }}" group="{{ group }}" mode=0700 state=directory - authorized_key: user="{{ user }}" key="{{ item.key }}" key_options='command="cd {{ pool }}/{{ item.host }};borg serve --restrict-to-path {{ pool }}/{{ item.host }}",no-port-forwarding,no-X11-forwarding,no-pty' with_items: auth_users - file: path="{{ home }}/.ssh/authorized_keys" owner="{{ user }}" group="{{ group }}" mode=0600 state=file - file: path="{{ pool }}/{{ item.host }}" owner="{{ user }}" group="{{ group }}" mode=0700 state=directory with_items: auth_users Enhancements ------------ As this chapter only describes a simple and effective setup it could be further enhanced when supporting (a limited set) of client supplied commands. A wrapper for starting `borg serve` could be written. Or borg itself could be enhanced to autodetect it runs under SSH by checking the `SSH_ORIGINAL_COMMAND` environment variable. This is left open for future improvements. When extending ssh autodetection in borg no external wrapper script is necessary and no other interpreter or apllication has to be deployed. See also -------- * `SSH Daemon manpage `_ * `Ansible `_