Install the configuration required for agent registration to work

It's actually taken care of for the vm provisioning part but not for bare metal
machines. So this aims at fixing them both by installing the required yaml by puppet.

Refs. swh/infra/sysadm-environment#5032

data/common/common.yaml

@@ -4323,3 +4323,6 @@ preseeding::vhost::docroot::mode: "2775"
 preseeding::vhost::ssl_protocol: "%{hiera('apache::ssl_protocol')}"
 preseeding::vhost::ssl_honorcipherorder: "%{hiera('apache::ssl_honorcipherorder')}"
 preseeding::vhost::ssl_cipher: "%{hiera('apache::ssl_cipher')}"
+
+rancher::rke2::agent::config:
+  snapshotter: native

site-modules/profile/manifests/zfs/rancher.pp

@@ -11,4 +11,40 @@ class profile::zfs::rancher {
     mountpoint  => '/var/lib/rancher',
     require     => Zpool['data'],
   }
+
+  # Install the necessary 50-snapshotter.yaml configuration so rke2-agent.service
+  # actually starts.
+  $config_content = lookup('rancher::rke2::agent::config')
+
+  file {"/etc/rancher":
+    ensure => directory,
+    owner  => "root",
+    group  => "root",
+    mode   => '0755',
+  }
+
+  file {"/etc/rancher/rke2":
+    ensure => directory,
+    owner  => "root",
+    group  => "root",
+    mode   => '0755',
+    require => File["/etc/rancher"],
+  }
+
+  file {"/etc/rancher/rke2/config.yaml.d":
+    ensure => directory,
+    owner  => "root",
+    group  => "root",
+    mode   => '0755',
+    require => File["/etc/rancher/rke2"],
+  }
+
+  file {"/etc/rancher/rke2/config.yaml.d/50-snapshotter.yaml":
+    owner  => "root",
+    group  => "root",
+    mode   => '0644',
+    content => inline_yaml($config_content),
+    # content => "{\n  \"snapshotter\": \"native\"\n}",
+    require => File["/etc/rancher/rke2/config.yaml.d"],
+  }
 }