make sure nmstate is installed before generating ISO

Add nmstate as a dependency before a deployment.
Also include a fail message in the generate ISO
step if nmstatectl command is missing.

README.md

@@ -62,13 +62,14 @@ Requires the following to be installed on the deployment host:
 - [kubectl + oc](https://docs.openshift.com/container-platform/4.10/cli_reference/openshift_cli/getting-started-cli.html)
 - [pyghmi](https://pypi.org/project/pyghmi/) #For PXE deployment
 - [ipmitool](https://github.com/ipmitool/ipmitool) #For PXE deployment
+- [nmstate](https://github.com/nmstate) # For baremetal deployment
 
 
 **Important Note** The `openshift-clients` package is part of the [Red Hat OpenShift Container Platform Subscription](https://access.redhat.com/downloads/content/290/). The repo [must be activated on the bastion host](https://docs.openshift.com/container-platform/4.12/cli_reference/openshift_cli/getting-started-cli.html#cli-installing-cli-rpm_cli-developer-commands) before the dependency installation. It is used for the post-installation cluster validation steps.
 
 
 ```bash
-dnf -y install ansible python3-netaddr skopeo podman openshift-clients ipmitool python3-pyghmi python3-jmespath
+dnf -y install ansible python3-netaddr skopeo podman openshift-clients ipmitool python3-pyghmi python3-jmespath nmstate
 ```
 
 There's also some required Ansible modules that can be installed with the following command:

roles/generate_agent_iso/tasks/main.yml

@@ -5,12 +5,22 @@
     mode: 0755
     recurse: true
 
-- name: Generate ISO
-  ansible.builtin.shell:
-    cmd: "{{ agent_based_installer_path }} --log-level=debug agent create image"
-    chdir: "{{ manifests_dir }}"
-  environment:
-    XDG_RUNTIME_DIR: "{{ config_file_path }}"
+- name: Generate an ISO and print message if there is a failure
+  block:
+    - name: Generate ISO
+      ansible.builtin.shell:
+        cmd: "{{ agent_based_installer_path }} --log-level=debug agent create image"
+        chdir: "{{ manifests_dir }}"
+      environment:
+        XDG_RUNTIME_DIR: "{{ config_file_path }}"
+      register: gen_iso
+  rescue:
+    - name: Print message about nmstate package missing
+      fail:
+        msg: "nmstate package missing in the bastion. See Dependencies section in README.md for more details."
+      when:
+        - gen_iso.stderr is defined
+        - gen_iso.stderr | regex_search("nmstatectl(.*) executable file not found")
 
 - name: Put discovery iso in http store
   delegate_to: http_store