[virt facts] recognize containerd as a container (#72210)

Change:
- containerd is now recognized as container tech

Test Plan:
- Tested with Docker inside Github Actions in a private repo:

        "ansible_virtualization_role": "guest",
        "ansible_virtualization_tech_guest": [
            "containerd",
            "container",
            "VirtualPC"
        ],
        "ansible_virtualization_tech_host": [],
        "ansible_virtualization_type": "containerd",

Tickets:
- Fixes #66304 because this is what docker containers show up as
  in Github Actions.

Signed-off-by: Rick Elrod <rick@elrod.me>

changelogs/fragments/66304-facts_containerd.yml

@@ -0,0 +1,2 @@
+minor_changes:
+  - virtual facts - containerd cgroup is now recognized as container tech (https://github.com/ansible/ansible/issues/66304).

lib/ansible/module_utils/facts/virtual/linux.py

@@ -61,6 +61,12 @@ class LinuxVirtual(Virtual):
                         virtual_facts['virtualization_type'] = 'lxc'
                         virtual_facts['virtualization_role'] = 'guest'
                         found_virt = True
+                if re.search('/system.slice/containerd.service', line):
+                    guest_tech.add('containerd')
+                    if not found_virt:
+                        virtual_facts['virtualization_type'] = 'containerd'
+                        virtual_facts['virtualization_role'] = 'guest'
+                        found_virt = True
 
         # lxc does not always appear in cgroups anymore but sets 'container=lxc' environment var, requires root privs
         if os.path.exists('/proc/1/environ'):
@@ -105,7 +111,7 @@ class LinuxVirtual(Virtual):
                 found_virt = True
 
         # ensure 'container' guest_tech is appropriately set
-        if guest_tech.intersection(set(['docker', 'lxc', 'podman', 'openvz'])) or systemd_container:
+        if guest_tech.intersection(set(['docker', 'lxc', 'podman', 'openvz', 'containerd'])) or systemd_container:
             guest_tech.add('container')
 
         if os.path.exists("/proc/xen"):