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diff --git a/nixos/doc/manual/from_md/configuration/sshfs-file-systems.section.xml b/nixos/doc/manual/from_md/configuration/sshfs-file-systems.section.xml new file mode 100644 index 00000000000..5d74712f35d --- /dev/null +++ b/nixos/doc/manual/from_md/configuration/sshfs-file-systems.section.xml @@ -0,0 +1,139 @@ +<section xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink" xml:id="sec-sshfs-file-systems"> + <title>SSHFS File Systems</title> + <para> + <link xlink:href="https://github.com/libfuse/sshfs">SSHFS</link> is + a + <link xlink:href="https://en.wikipedia.org/wiki/Filesystem_in_Userspace">FUSE</link> + filesystem that allows easy access to directories on a remote + machine using the SSH File Transfer Protocol (SFTP). It means that + if you have SSH access to a machine, no additional setup is needed + to mount a directory. + </para> + <section xml:id="sec-sshfs-interactive"> + <title>Interactive mounting</title> + <para> + In NixOS, SSHFS is packaged as <package>sshfs</package>. Once + installed, mounting a directory interactively is simple as + running: + </para> + <programlisting> +$ sshfs my-user@example.com:/my-dir /mnt/my-dir +</programlisting> + <para> + Like any other FUSE file system, the directory is unmounted using: + </para> + <programlisting> +$ fusermount -u /mnt/my-dir +</programlisting> + </section> + <section xml:id="sec-sshfs-non-interactive"> + <title>Non-interactive mounting</title> + <para> + Mounting non-interactively requires some precautions because + <literal>sshfs</literal> will run at boot and under a different + user (root). For obvious reason, you can’t input a password, so + public key authentication using an unencrypted key is needed. To + create a new key without a passphrase you can do: + </para> + <programlisting> +$ ssh-keygen -t ed25519 -P '' -f example-key +Generating public/private ed25519 key pair. +Your identification has been saved in test-key +Your public key has been saved in test-key.pub +The key fingerprint is: +SHA256:yjxl3UbTn31fLWeyLYTAKYJPRmzknjQZoyG8gSNEoIE my-user@workstation +</programlisting> + <para> + To keep the key safe, change the ownership to + <literal>root:root</literal> and make sure the permissions are + <literal>600</literal>: OpenSSH normally refuses to use the key if + it’s not well-protected. + </para> + <para> + The file system can be configured in NixOS via the usual + <link linkend="opt-fileSystems">fileSystems</link> option. Here’s + a typical setup: + </para> + <programlisting language="bash"> +{ + system.fsPackages = [ pkgs.sshfs ]; + + fileSystems."/mnt/my-dir" = { + device = "my-user@example.com:/my-dir/"; + fsType = "sshfs"; + options = + [ # Filesystem options + "allow_other" # for non-root access + "_netdev" # this is a network fs + "x-systemd.automount" # mount on demand + + # SSH options + "reconnect" # handle connection drops + "ServerAliveInterval=15" # keep connections alive + "IdentityFile=/var/secrets/example-key" + ]; + }; +} +</programlisting> + <para> + More options from <literal>ssh_config(5)</literal> can be given as + well, for example you can change the default SSH port or specify a + jump proxy: + </para> + <programlisting language="bash"> +{ + options = + [ "ProxyJump=bastion@example.com" + "Port=22" + ]; +} +</programlisting> + <para> + It’s also possible to change the <literal>ssh</literal> command + used by SSHFS to connect to the server. For example: + </para> + <programlisting language="bash"> +{ + options = + [ (builtins.replaceStrings [" "] ["\\040"] + "ssh_command=${pkgs.openssh}/bin/ssh -v -L 8080:localhost:80") + ]; + +} +</programlisting> + <note> + <para> + The escaping of spaces is needed because every option is written + to the <literal>/etc/fstab</literal> file, which is a + space-separated table. + </para> + </note> + <section xml:id="sec-sshfs-troubleshooting"> + <title>Troubleshooting</title> + <para> + If you’re having a hard time figuring out why mounting is + failing, you can add the option + <literal>"debug"</literal>. This enables a verbose log + in SSHFS that you can access via: + </para> + <programlisting> +$ journalctl -u $(systemd-escape -p /mnt/my-dir/).mount +Jun 22 11:41:18 workstation mount[87790]: SSHFS version 3.7.1 +Jun 22 11:41:18 workstation mount[87793]: executing <ssh> <-x> <-a> <-oClearAllForwardings=yes> <-oServerAliveInterval=15> <-oIdentityFile=/var/secrets/wrong-key> <-2> <my-user@example.com> <-s> <sftp> +Jun 22 11:41:19 workstation mount[87793]: my-user@example.com: Permission denied (publickey). +Jun 22 11:41:19 workstation mount[87790]: read: Connection reset by peer +Jun 22 11:41:19 workstation systemd[1]: mnt-my\x2ddir.mount: Mount process exited, code=exited, status=1/FAILURE +Jun 22 11:41:19 workstation systemd[1]: mnt-my\x2ddir.mount: Failed with result 'exit-code'. +Jun 22 11:41:19 workstation systemd[1]: Failed to mount /mnt/my-dir. +Jun 22 11:41:19 workstation systemd[1]: mnt-my\x2ddir.mount: Consumed 54ms CPU time, received 2.3K IP traffic, sent 2.7K IP traffic. +</programlisting> + <note> + <para> + If the mount point contains special characters it needs to be + escaped using <literal>systemd-escape</literal>. This is due + to the way systemd converts paths into unit names. + </para> + </note> + </section> + </section> +</section> |