rancher: use a zfs dataset for /var/lib/kubelet to use the local storage for EmptyDir volumes

Related to T4506

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

+# Handle /var/lib/kubelet partition as zfs mountpoint
+# To reduce the disk usage and use local storage when the second hard
+# drive is configured to a local storage in terraform
+class profile::zfs::kubelet {
+  # as it's for rancher, we consider the zpool['data'] is
+  # already installed by profile::zfs::docker
+  zfs { 'data/kubelet':
+    ensure      => present,
+    atime       => 'off',
+    compression => 'zstd',
+    mountpoint  => '/var/lib/kubelet',
+    require     => Zpool['data'],
+  }
+}

site-modules/role/manifests/rancher_node.pp

 class role::rancher_node inherits role::swh_base {
   include profile::docker
   include profile::zfs::docker
+  include profile::zfs::kubelet
 }

[Phabricator Migration user]

Some references in the commit message have been migrated:

• T4506 is now infra/sysadm-environment#4506