View source for Proxmox Linux Container

{{outdated|See [[Proxmox]] for instructions that apply to more recent versions of nixpkgs and proxmox.}}

= Building Proxmox Linux Containers with Nix =

You can use 'make-system-tarball' to create a Linux Container that can run on Proxmox, for example like https://codeberg.org/raboof/nix-mastodon-bot/src/branch/main/default.nix#L31

= NixOS =

With a small amount of work, it is possible to use NixOS as a LXC container under Proxmox.

== Generate a container tarball ==
A better way to deploy a NixOS container tarball on Proxmox is described at [[Proxmox Virtual Environment#LXC]].

== Finding a container tarball ==

Go to https://hydra.nixos.org/project/nixos, choose a release (small ones don't have the tarball we need), and open its Jobs tab.
On that page, search for <strong>nixos.containerTarball</strong>, open the link corresponding to your architecture (probably x86_64). Choose the latest success and click on the number. That is the ID of the result. Under <em>Build products</em>, download the <strong>system-tarball</strong>, which will be named <tt>nixos-system-x86_64-linux.tar.xz</tt>.

Note the Build ID, it will be used when renaming the tarball... right when it's downloaded:

<pre>
mv nixos-system-x86_64-linux.tar.xz nixos-${RELEASE}-default_${BUILDID}_amd64.tar.xz
</pre>

This is a proxmox convention, and is useful to follow.

== Preparing the container ==

But first, you will need to upload the container tarball to the storage.

Then, once this is done, you will need to access the CLI for the proxmox host. SSH or the web CLI will be fine.

=== CLI operations ===

In the CLI, create a container using the following command. If created as a template, I recommend setting a memorable ID.

<pre>
pct create 99999 \
  --description nixos-template \
  local:vztmpl/nixos-${RELEASE}-default_${BUILDID}_amd64.tar.xz \
  -ostype unmanaged \
  -net0 name=eth0 \
  -storage local-lvm
</pre>

{{tip|use tab-completion in the CLI for the <tt>local:...</tt> path!}}

Note that in the previous command, the <tt>-ostype</tt> option is necessary; this way Proxmox will not try to do <em>fancy stuff</em> to the system.

The last step using the CLI, edit <tt>/etc/pve/lxc/99999.conf</tt> to add this line:
<pre>
lxc.init.cmd: /sbin/init
</pre>

Before NixOS version 21.11 it was
<pre>
lxc.init.cmd: /init
</pre>
.

=== Creating a template ===

It is not be possible to use the facilities to create a NixOS container under Proxmox. It is possible, though, to create a template that may be cloned as a base. In the GUI, with the container selected, click the <em>More</em> menu at the top, then <em>Convert to template</em>. Accept.

To create a new NixOS container, you can then clone the template instead of doing the preceding steps.
== Expected issues ==
=== Entering the container by <code>pct enter</code> ===

enter a (nixos) container from the proxmox host
: <syntaxhighlight lang="shell">[root@proxmox:~]# pct enter <vmid></syntaxhighlight>
: <syntaxhighlight lang="shell">sh-5.2#</syntaxhighlight>

: <s>set (missing) environment variables</s>
:: <s><syntaxhighlight lang="shell">sh-5.2# source /etc/set-environment</syntaxhighlight></s>
:: <s><syntaxhighlight lang="shell">sh-5.2#</syntaxhighlight></s>
or
: set (missing) environment variables with <code>[[wikipedia:en:dot (command)#source|.]]</code>
:: <syntaxhighlight lang="shell">sh-5.2# . /etc/profile</syntaxhighlight>
:: <syntaxhighlight lang="bash">[root@nixos:~]#</syntaxhighlight><syntaxhighlight lang="shell">
[root@nixos:~] /run/current-system/activate
</syntaxhighlight>
<!--
or
: set (missing) environment variables by opening a new shell
:: <syntaxhighlight lang="shell">sh-5.2# sh -l</syntaxhighlight>
:: <syntaxhighlight lang="bash">[root@nixos:~]#</syntaxhighlight>
-->

=== nixos-rebuild switch ===
<code>nixos-rebuild switch</code> may fail with errors for special mount points. This does not look like it affects the container.

<pre>
[root@nixos:/]# nixos-rebuild switch
building Nix...
building the system configuration...
activating the configuration...
setting up /etc...
mount: /dev: cannot remount devtmpfs read-write, is write-protected.
mount: /dev/pts: cannot remount devpts read-write, is write-protected.
mount: /dev/shm: cannot remount tmpfs read-write, is write-protected.
mount: /proc: cannot remount proc read-write, is write-protected.
mount: /run: cannot remount tmpfs read-write, is write-protected.
mount: /run/keys: cannot mount ramfs read-only.
mount: /run/wrappers: cannot remount tmpfs read-write, is write-protected.
setting up tmpfiles
warning: error(s) occurred while switching to the new configuration
</pre>

=== Black Console in Proxmox ===

The Proxmox console may appear black when launched. It is at the login prompt but no existing text is rendered. Just type "root" and hit enter and new text will get rendered just fine. If you are still unable to get the console to render, you can try changing the console to `/dev/console` instead of the standard tty.