Mosh: Difference between revisions

Latest revision as of 02:56, 13 November 2022

Mosh is an alternative SSH terminal. It has support for roaming, local echo and uses UDP for transport. It also aims to improve responsiveness on intermittent, and high latency connections.

See the mosh Package and mosh Options

Instalation

Client

Install the mosh package.

Server

Enable the programs.mosh module. You can simply add the following into your /etc/nixos/configuration.nix:

# Enable mosh, the ssh alternative when client has bad connection
# Opens UDP ports 60000 ... 61000
programs.mosh.enable = true;

Usage

With mosh installed on both the client and server, connect by running:

$ mosh user@server

Note that mosh uses SSH for authentication and initialization, so it will respect aliases and other options in .ssh/config. You can also specify SSH options using the --ssh argument. For example, to use port 1122 instead of 22, you can either use Port 1122 in SSH config, or use mosh with the --ssh argument:

$ mosh --ssh='ssh -p 1122' user@server

More information is available at mosh.org or using man mosh

Troubleshooting

Missing `/run/user/1000`

Using a mosh session, $XDG_RUNTIME_DIR (/run/user/1000) doesn't exist and causes issues such as:

nix-shell failing with Error in tempdir() using /run/user/1000/nix-shell.XXXXX

This is caused by the way mosh handles logging-in to the system, the login is actually handled by a short ssh session, which ends immediately. logind, as it is used, closes the user's session and cleans up behind, since there is no lingering configured by default.

To enable lingering use:

$ loginctl enable-linger $USER

Then reconnect with mosh. Note that lingering is enabled by default in NixOS >= 16.09.

As a workaround, it is also possible to set an alias in the user's shell on the server wrapping mosh-server to keep the session around. ^[1]

alias mosh-server = "systemd-run --user --scope mosh-server"

The locale requested by LANG=*** isn't available here.

This error occurs when trying to connect to a linux server (non-NixOS distribution) on which mosh-server has been installed via nix. The easy solution is to set LOCALE_ARCHIVE to your OS locale-archive in your .profile or .zshenv:

export LOCALE_ARCHIVE=/usr/lib/locale/locale-archive

References

↑ issue#29234

[1] ssue#29234

[1]

@@ Line 1: / Line 1: @@
-{{expansion|Missing installation and configuration of both server and client.}}
+[https://mosh.org/ Mosh] is an alternative SSH terminal. It has support for roaming, local echo and uses UDP for transport. It also aims to improve responsiveness on intermittent, and high latency connections.
+See the [https://search.nixos.org/packages?show=mosh&query=mosh mosh Package] and [https://search.nixos.org/options?query=programs.mosh mosh Options]
+== Instalation ==
+=== Client ===
+Install the <code>[https://search.nixos.org/packages?show=mosh&query=mosh mosh]</code> package.
+=== Server ===
+Enable the <code>[https://search.nixos.org/options?query=programs.mosh programs.mosh]</code> module. You can simply add the following into your <code>/etc/nixos/configuration.nix</code>:
+<syntaxhighlight lang=nix>
+# Enable mosh, the ssh alternative when client has bad connection
+# Opens UDP ports 60000 ... 61000
+programs.mosh.enable = true;
+</syntaxhighlight>
+== Usage ==
+With mosh installed on both the client and server, connect by running:
+<syntaxhighlight lang=console>
+$ mosh user@server
+</syntaxhighlight>
+Note that mosh uses SSH for authentication and initialization, so it will respect aliases and other options in <code>.ssh/config</code>. You can also specify SSH options using the <code>--ssh</code> argument. For example, to use port 1122 instead of 22, you can either use <code>Port 1122</code> in SSH config, or use mosh with the <code>--ssh</code> argument:
+<syntaxhighlight lang=console>
+$ mosh --ssh='ssh -p 1122' user@server
+</syntaxhighlight>
+More information is available at [https://mosh.org/#usage mosh.org] or using <code>[https://manpages.debian.org/bullseye/mosh/mosh.1.en.html man mosh]</code>
 == Troubleshooting ==
@@ Line 17: / Line 51: @@
 </syntaxhighlight>
-Then reconnect with mosh.
+Then reconnect with mosh. Note that lingering is enabled by default in NixOS >= 16.09.
 As a workaround, it is also possible to set an alias in the user's shell on the server wrapping <code>mosh-server</code> to keep the session around.
@@ Line 39: / Line 73: @@
 == References ==
 <references />
+[[Category:Applications]]