dynamically get the nodeport host (#4158)

Greetings,

This is an update to the example doc of [`Using
Kubevirt`](https://ansible.readthedocs.io/projects/molecule/examples/kubevirt).
The purpose is to **dynamically** get the NodePort host to replace the
hardcoded hostname that is used for the VM SSH connection.

**The problem we solved**
By fetching the `hostname` dynamically, we avoid using a pre-defined
host for the VM SSH connection, that will reduce the the potential
failures by the connection problem with the host. In this update, the
hostname for the SSH connection is fetched dynamically, which is the K8S
node where the VM is running.

I get this tested in our environment with @jangel97

Thanks.

Co-authored-by: Hong Yao <[email protected]>

Author: yahoon

docs/examples/kubevirt.md

@@ -40,6 +40,9 @@ rules:
   - apiGroups: [""]
     resources: ["services"]
     verbs: ["get", "list", "watch", "create", "delete", "patch", "edit"]
+  - apiGroups: [""]
+    resources: ["pods"]
+    verbs: ["get", "list"]
 ---
 apiVersion: rbac.authorization.k8s.io/v1
 kind: RoleBinding
@@ -67,17 +70,17 @@ You will need to substitute the following placeholders:
 
 - This example is using ephemeral VMs, which enhance the speed of VM creation and cleanup. However, it is important to note that any data in the system will not be retained if the VM is rebooted.
 - You don't need to worry about setting up SSH keys. The `create.yml` Ansible playbook takes care of configuring a temporary SSH key.
+- The hostname for SSH connection to the VM is fetched dynamically, which is the K8S node where the VM is running.
 
 ## Config playbook
 
 ```yaml title="molecule.yml"
 {!tests/fixtures/integration/test_command/molecule/kubevirt/molecule.yml!}
 ```
 
-Please, replace the following parameters:
+Please, replace the following parameter:
 
 - `<Kubernetes VM Namespace>`: This should be replaced with the namespace in Kubernetes where you intend to create the KubeVirt VMs.
-- `<Kubernetes Node FQDN>`: Change this to the fully qualified domain name (FQDN) of the Kubernetes node that Ansible will attempt to SSH into via the Service NodePort.
 
 ```yaml title="requirements.yml"
 {!tests/fixtures/integration/test_command/molecule/kubevirt/requirements.yml!}

tests/fixtures/integration/test_command/molecule/kubevirt/destroy.yml

@@ -14,7 +14,7 @@
       loop_control:
         loop_var: vm
 
-    - name: Delete VM Instance in KubeVirt
+    - name: Delete NodePort Service in KubeVirt
       kubernetes.core.k8s:
         state: absent
         kind: Service

tests/fixtures/integration/test_command/molecule/kubevirt/molecule.yml

@@ -10,15 +10,13 @@ platforms:
     namespace: <Kubernetes VM Namespace>
     ssh_service:
       type: NodePort
-      nodeport_host: <Kubernetes Node FQDN>
     ansible_user: cloud-user
     memory: 1Gi
   - name: rhel8
     image: registry.redhat.io/rhel8/rhel-guest-image
     namespace: <Kubernetes VM Namespace>
     ssh_service:
       type: NodePort
-      nodeport_host: <Kubernetes Node FQDN>
     ansible_user: cloud-user
     memory: 1Gi
 provisioner:

tests/fixtures/integration/test_command/molecule/kubevirt/tasks/create_vm.yml

@@ -57,3 +57,16 @@
                       - [ sudo, yum, install, -y, qemu-guest-agent ]  # Installs qemu-guest-agent
                       - [ sudo, systemctl, start, qemu-guest-agent ]  # Starts qemu-guest-agent
                 name: cloudinitdisk
+
+- name: Fetch VM pod info
+  kubernetes.core.k8s_info:
+    api_version: v1
+    kind: Pod
+    label_selectors:
+      - "vm.kubevirt.io/name={{ vm.name }}"
+    namespace: "{{ vm.namespace }}"
+  register: vm_pod_info
+
+- name: Extract the nodename from the VM pod info
+  ansible.builtin.set_fact:
+    nodeport_host: "{{ vm_pod_info.resources | map(attribute='spec.nodeName') | list | first }}"

tests/fixtures/integration/test_command/molecule/kubevirt/tasks/create_vm_dictionary.yml

@@ -17,8 +17,8 @@
       {{
         molecule_systems | default({}) | combine({
           vm.name: {
-            'ansible_user': 'cloud-user',
-            'ansible_host': vm.ssh_service.nodeport_host,
+            'ansible_user': vm.ansible_user,
+            'ansible_host': nodeport_host,
             'ansible_ssh_port': ssh_service_address,
             'ansible_ssh_private_key_file': temporary_ssh_key_path
           }