diff --git a/README.md b/README.md
index 94a62befb..d34a471ee 100644
--- a/README.md
+++ b/README.md
@@ -91,6 +91,7 @@ This project supports below scenarios for end-to-end guest operating system vali
 | openSUSE Leap 15.3 and later                  | :heavy_check_mark:               |                          | :heavy_check_mark:                 |
 | BCLinux 8.x                                   | :heavy_check_mark:               |                          | :heavy_check_mark:                 |
 | BCLinux-for-Euler 21.10                       | :heavy_check_mark:               |                          | :heavy_check_mark:                 |
+| Red Hat Enterprise Linux CoreOS (RHCOS) 4.13 and later                    |                                  | :heavy_check_mark:       | :heavy_check_mark:                 |
 
 **Notes**
 1. This compatible guest operating systems list is used for this project only. For guest operating system support status on ESXi, please refer to [VMware Compatibility Guide](https://www.vmware.com/resources/compatibility/search.php?deviceCategory=software&testConfig=16).
diff --git a/common/collect_ovf_vm_config.yml b/common/collect_ovf_vm_config.yml
index be66a72cc..14438ed92 100644
--- a/common/collect_ovf_vm_config.yml
+++ b/common/collect_ovf_vm_config.yml
@@ -191,7 +191,7 @@
       ansible.builtin.set_fact:
         ovf_vm_guest_os: "{{ guest_detailed_data_dict.prettyName | default('') }}"
         ovf_vm_guest_build: "{{ guest_detailed_data_dict.kernelVersion | default('') }}"
-        ovf_vm_guest_bitness: "{{ guest_detailed_data_dict.bitness | default('')  }}"
+        ovf_vm_guest_bitness: "{{ guest_detailed_data_dict.bitness | default('') }}"
 
     - name: "Set fact of Linux guest OS distribution"
       block:
diff --git a/common/create_temp_file_dir.yml b/common/create_temp_file_dir.yml
index 95b28a6a6..7a698716a 100644
--- a/common/create_temp_file_dir.yml
+++ b/common/create_temp_file_dir.yml
@@ -3,10 +3,10 @@
 ---
 # Create a temporary file or directory
 # Parameters:
+#   tmp_state: file or directory. By default, temporary file will be created.
 #   tmp_dir: (Optional) the location where temporary file or diretotry will be created.
-#   tmp_state: file or directory. By default, temporary file will be created
-#   tmp_prefix: the prefix of temporary file or directory
-#   tmp_suffix: the suffix of temporar file or directory
+#   tmp_prefix: (Optional) the prefix of temporary file or directory.
+#   tmp_suffix: (Optional) the suffix of temporar file or directory.
 # Return:
 #   tmp_path: the path to temporary file or directory
 #
@@ -31,11 +31,11 @@
 - name: "Modify the mode of temporary file"
   ansible.builtin.file:
     path: "{{ tmp_path }}"
-    mode: "0644"
+    mode: "0666"
   when: tmp_state == "file"
 
 - name: "Modify the mode of temporary directory"
   ansible.builtin.file:
     path: "{{ tmp_path }}"
-    mode: "0755"
+    mode: "0777"
   when: tmp_state == "directory"
diff --git a/common/vm_remove_serial_port.yml b/common/vm_remove_serial_port.yml
index 9bf5a3980..f2d29a761 100644
--- a/common/vm_remove_serial_port.yml
+++ b/common/vm_remove_serial_port.yml
@@ -4,9 +4,9 @@
 # Remove a serial port to VM by using output file
 # Parameter:
 #   vm_serial_port_file_path: The serial port output file on datastore.
-
-# Before removing serial port, remove the serial port output file
-- include_tasks: esxi_check_delete_datastore_file.yml
+#
+- name: "Remove the serial port output file before removing serial port"
+  include_tasks: esxi_check_delete_datastore_file.yml
   vars:
     file_in_datastore: "{{ datastore }}"
     file_in_datastore_path: "{{ vm_serial_port_file_path.split(']')[-1].strip(' ') }}"
@@ -28,3 +28,14 @@
 
 - name: "Display result of removing serial port"
   ansible.builtin.debug: var=remove_serial_port
+
+- name: "Check serial port is removed"
+  ansible.builtin.assert:
+    that:
+      - remove_serial_port.changed is defined
+      - remove_serial_port.changed
+    fail_msg: "Failed to remove serial port from VM"
+
+- name: "Clean serial port output file path on datastore"
+  ansible.builtin.set_fact:
+    vm_serial_port_file_path: ""
diff --git a/common/vm_upgrade_hardware_version.yml b/common/vm_upgrade_hardware_version.yml
index 9f5e9a9ff..818959e18 100644
--- a/common/vm_upgrade_hardware_version.yml
+++ b/common/vm_upgrade_hardware_version.yml
@@ -18,6 +18,7 @@
 - name: "Update VM hardware version"
   ansible.builtin.set_fact:
     vm_hardware_version: "{{ vm_upgrade_hw_result.instance.hw_version }}"
+    vm_hardware_version_num: "{{ vm_upgrade_hw_result.instance.hw_version.split('-')[1] }}"
 
 - ansible.builtin.debug:
     msg: "VM hardware version is upgraded to: {{ vm_hardware_version }}"
diff --git a/linux/check_inbox_driver/check_inbox_driver.yml b/linux/check_inbox_driver/check_inbox_driver.yml
index 93b6e3ecb..fd7f8ab26 100644
--- a/linux/check_inbox_driver/check_inbox_driver.yml
+++ b/linux/check_inbox_driver/check_inbox_driver.yml
@@ -9,7 +9,6 @@
 - name: check_inbox_driver
   hosts: localhost
   gather_facts: false
-  vars:
   tasks:
     - name: "Initialized inbox drivers' versions dict"
       ansible.builtin.set_fact:
diff --git a/linux/check_quiesce_snapshot_custom_script/check_quiesce_snapshot_custom_script.yml b/linux/check_quiesce_snapshot_custom_script/check_quiesce_snapshot_custom_script.yml
index d2ead3a78..c8f19dcb1 100644
--- a/linux/check_quiesce_snapshot_custom_script/check_quiesce_snapshot_custom_script.yml
+++ b/linux/check_quiesce_snapshot_custom_script/check_quiesce_snapshot_custom_script.yml
@@ -11,7 +11,8 @@
   tasks:
     - name: "Test case block"
       block:
-        - include_tasks: ../setup/test_setup.yml
+        - name: "Test setup"
+          include_tasks: ../setup/test_setup.yml
           vars:
             skip_test_no_vmtools: true
 
@@ -23,16 +24,19 @@
           when: guest_os_ansible_distribution == 'FreeBSD'
 
         # Take quiesce snapshot
-        - name: Set quiesce snapshot variables
+        - name: "Set quiesce snapshot variables"
           ansible.builtin.set_fact:
             qs_snapshot_name: "quiesce_snapshot_{{ lookup('pipe', 'date +%Y-%m-%d-%H-%M-%S') }}"
             backup_script_dir: "/etc/vmware-tools/backupScripts.d"
             vss_shell_script: "vss_script_sh.sh"
             vss_bin_script: "vss_script_bin_{{ guest_os_bit | replace('-', '') }}"
-            vss_log_path: "/vss.log"
+            vss_log_path: |-
+              {%- if guest_os_ansible_distribution in ['Flatcar', 'RHCOS'] -%}/var/vss.log
+              {%- else -%}/vss.log
+              {%- endif -%}
             vss_content: ""
 
-        # Copy vss_script_sh.sh to /etc/vmware-tools/backupScripts.d/vss_script_sh.sh
+        # Create vss_script_sh.sh under /etc/vmware-tools/backupScripts.d/
         - name: "Create backup script dir {{ backup_script_dir }}"
           ansible.builtin.file:
             path: "{{ backup_script_dir }}"
@@ -40,15 +44,15 @@
             mode: 0755
           delegate_to: "{{ vm_guest_ip }}"
 
-        - name: "Copy custom script {{ vss_shell_script }}"
-          ansible.builtin.copy:
+        - name: "Add custom shell script {{ vss_shell_script }}"
+          ansible.builtin.template:
             src: "{{ vss_shell_script }}"
             dest: "{{ backup_script_dir }}/{{ vss_shell_script }}"
             mode: 0755
           delegate_to: "{{ vm_guest_ip }}"
 
         # Copy pre-freeze-script and post-thaw-script to /usr/sbin/
-        - name: Copy custom script pre-freeze-script and post-thaw-script to /usr/sbin
+        - name: "Copy custom binary scripts pre-freeze-script and post-thaw-script to /usr/sbin"
           ansible.builtin.copy:
             src: "{{ vss_bin_script }}"
             dest: "/usr/sbin/{{ item }}"
@@ -57,26 +61,21 @@
             - pre-freeze-script
             - post-thaw-script
           delegate_to: "{{ vm_guest_ip }}"
-          when: guest_os_ansible_distribution != 'Flatcar'
+          when: guest_os_ansible_distribution not in ['Flatcar', 'RHCOS']
 
-        # Ensure /vss.log is absent
         - name: "Remove {{ vss_log_path }} if it exists"
           ansible.builtin.file:
             path: "{{ vss_log_path }}"
             state: absent
           delegate_to: "{{ vm_guest_ip }}"
 
-        - include_tasks: ../../common/vm_take_snapshot.yml
+        - name: "Take quiesce snapshot"
+          include_tasks: ../../common/vm_take_snapshot.yml
           vars:
             snapshot_name: "{{ qs_snapshot_name }}"
             is_quiesce: "yes"
             dump_memory: "no"
 
-        # After snapshot is taken, check log file /vss.log in guest, which should have below contents:
-        # /usr/sbin/pre-freeze-script freeze
-        # /etc/vmware-tools/backupScripts.d/vss_script_sh.sh freeze
-        # /etc/vmware-tools/backupScripts.d/vss_script_sh.sh thaw
-        # /usr/sbin/post-thaw-script thaw
         - name: "Check {{ vss_log_path }} existence"
           include_tasks: ../utils/get_file_stat_info.yml
           vars:
@@ -87,45 +86,54 @@
             msg: "{{ vss_log_path }} doesn't exist after quiesce snapshot"
           when: not (guest_file_exists | bool)
 
-        # Retrieve /vss.log
-        - include_tasks: ../../common/vm_guest_file_operation.yml
+        - name: "Retrieve {{ vss_log_path }}"
+          include_tasks: ../../common/vm_guest_file_operation.yml
           vars:
             operation: "fetch_file"
             src_path: "{{ vss_log_path }}"
             dest_path: "{{ current_test_log_folder }}{{ vss_log_path }}"
 
-        - name: "Get file content in /vss.log"
+        - name: "Get file content in {{ vss_log_path }}"
           ansible.builtin.shell: "cat {{ current_test_log_folder }}{{ vss_log_path }}"
           changed_when: false
           register: vss_content
 
-        # Test failed for non-Flatcar guest
-        - name: "{{ ansible_play_name }} failed"
-          ansible.builtin.fail:
-            msg: "{{ vss_log_path }} has incorrect content"
-          when: (guest_os_ansible_distribution != 'Flatcar') and
-              (( not vss_content ) or
-              ( vss_content.stdout_lines is undefined ) or
-              ( vss_content.stdout_lines | length != 4 ) or
-              ( vss_content.stdout_lines[0] != "/usr/sbin/pre-freeze-script freeze" ) or
-              ( vss_content.stdout_lines[1] != "/etc/vmware-tools/backupScripts.d/vss_script_sh.sh freeze" ) or
-              ( vss_content.stdout_lines[2] != "/etc/vmware-tools/backupScripts.d/vss_script_sh.sh thaw" ) or
-              ( vss_content.stdout_lines[3] != "/usr/sbin/post-thaw-script thaw" ))
+        # Guest OS is not Flatcar or RHCOS
+        # After quiesce snapshot is taken, guest log file /vss.log should have below contents:
+        # /usr/sbin/pre-freeze-script freeze
+        # /etc/vmware-tools/backupScripts.d/vss_script_sh.sh freeze
+        # /etc/vmware-tools/backupScripts.d/vss_script_sh.sh thaw
+        # /usr/sbin/post-thaw-script thaw
+        - name: "Check file content in {{ vss_log_path }}"
+          ansible.builtin.assert:
+            that:
+              - vss_content.stdout_lines is defined
+              - vss_content.stdout_lines | length == 4
+              - vss_content.stdout_lines[0] == "/usr/sbin/pre-freeze-script freeze"
+              - vss_content.stdout_lines[1] == "/etc/vmware-tools/backupScripts.d/vss_script_sh.sh freeze"
+              - vss_content.stdout_lines[2] == "/etc/vmware-tools/backupScripts.d/vss_script_sh.sh thaw"
+              - vss_content.stdout_lines[3] == "/usr/sbin/post-thaw-script thaw"
+            fail_msg: "{{ vss_log_path }} has incorrect content"
+          when: guest_os_ansible_distribution not in ['Flatcar', 'RHCOS']
 
-        # Test failed for Flatcar guest
-        - name: "{{ ansible_play_name }} failed"
-          ansible.builtin.fail:
-            msg: "{{ vss_log_path }} has incorrect content"
-          when: (guest_os_ansible_distribution == 'Flatcar') and
-             (( not vss_content ) or
-             ( vss_content.stdout_lines is undefined ) or
-             ( vss_content.stdout_lines | length != 2 ) or
-             ( vss_content.stdout_lines[0] != "/etc/vmware-tools/backupScripts.d/vss_script_sh.sh freeze") or
-             ( vss_content.stdout_lines[1] != "/etc/vmware-tools/backupScripts.d/vss_script_sh.sh thaw" ))
+        # Guest OS is Flatcar or RHCOS
+        # After quiesce snapshot is taken, guest log file /var/vss.log should have below contents:
+        # /etc/vmware-tools/backupScripts.d/vss_script_sh.sh freeze
+        # /etc/vmware-tools/backupScripts.d/vss_script_sh.sh thaw
+        - name: "Check file content in {{ vss_log_path }}"
+          ansible.builtin.assert:
+            that:
+              - vss_content.stdout_lines is defined
+              - vss_content.stdout_lines | length == 2
+              - vss_content.stdout_lines[0] == "/etc/vmware-tools/backupScripts.d/vss_script_sh.sh freeze"
+              - vss_content.stdout_lines[1] == "/etc/vmware-tools/backupScripts.d/vss_script_sh.sh thaw"
+            fail_msg: "{{ vss_log_path }} has incorrect content"
+          when: guest_os_ansible_distribution in ['Flatcar', 'RHCOS']
 
-        # Remove quiesce snapshot for successful test
-        - include_tasks: ../../common/vm_remove_snapshot.yml
+        - name: "Remove quiesce snapshot for successful test"
+          include_tasks: ../../common/vm_remove_snapshot.yml
           vars:
             snapshot_name: "{{ qs_snapshot_name }}"
       rescue:
-        - include_tasks: ../../common/test_rescue.yml
+        - name: "Test case failure"
+          include_tasks: ../../common/test_rescue.yml
diff --git a/linux/check_quiesce_snapshot_custom_script/vss_script_sh.sh b/linux/check_quiesce_snapshot_custom_script/vss_script_sh.sh
index cfc6e61de..b3d0ff543 100755
--- a/linux/check_quiesce_snapshot_custom_script/vss_script_sh.sh
+++ b/linux/check_quiesce_snapshot_custom_script/vss_script_sh.sh
@@ -1,3 +1,3 @@
 #!/bin/sh
-echo $0 $@ >> /vss.log
+echo $0 $@ >> {{ vss_log_path }}
 exit 0
diff --git a/linux/deploy_vm/collect_serial_port_log.yml b/linux/deploy_vm/collect_serial_port_log.yml
new file mode 100644
index 000000000..79f2573d6
--- /dev/null
+++ b/linux/deploy_vm/collect_serial_port_log.yml
@@ -0,0 +1,23 @@
+# Copyright 2023 VMware, Inc.
+# SPDX-License-Identifier: BSD-2-Clause
+---
+# Collect VM serial port log file
+#
+- name: "Collect VM serial port log"
+  when:
+    - vm_dir_name is defined
+    - vm_dir_name
+    - vm_serial_port_file_path is defined
+    - vm_serial_port_file_path
+  block:
+    - name: "Set fact of VM serial port log file name"
+      ansible.builtin.set_fact:
+        vm_serial_port_file_name: "{{ vm_serial_port_file_path.split()[-1] | basename }}"
+
+    - name: "Download VM serial port log file from datastore"
+      include_tasks: ../../common/esxi_download_datastore_file.yml
+      vars:
+        src_datastore: "{{ datastore }}"
+        src_file_path: "{{ vm_dir_name }}/{{ vm_serial_port_file_name }}"
+        dest_file_path: "{{ current_test_log_folder }}/{{ vm_serial_port_file_name }}"
+        download_file_fail_ignore: true
diff --git a/linux/deploy_vm/collect_vm_logs.yml b/linux/deploy_vm/collect_vm_logs.yml
index 74fd9865a..dd8e6461a 100644
--- a/linux/deploy_vm/collect_vm_logs.yml
+++ b/linux/deploy_vm/collect_vm_logs.yml
@@ -1,21 +1,32 @@
 # Copyright 2023 VMware, Inc.
 # SPDX-License-Identifier: BSD-2-Clause
 ---
-# Collect cloud-init logs for deploying Ubuntu live-server,
-# cloud image or Photon OVA.
+# Collect VM guest info and cloud-init logs for deploying Ubuntu live-server,
+# cloud image, VMware Photon OS OVA or Amazon Linux OVA.
 #
-- name: "Collect VM logs"
+- name: "Collect VM deployement logs"
+  when:
+    - vm_exists is defined
+    - vm_exists
   block:
     - name: "Get VM's power state"
       include_tasks: ../../common/vm_get_power_state.yml
 
-    - name: "Collect cloud-init logs"
+    - name: "Collect VM's guest info and cloud-init logs"
+      when:
+        - vm_power_state_get is defined
+        - vm_power_state_get == "poweredOn"
       block:
+        - name: "Get VMware Tools status"
+          include_tasks: ../../common/vm_get_vmtools_status.yml
+
+        # VM's guest info will be collected by log plugin
         - name: "Get VM's guest info"
           include_tasks: ../../common/vm_get_guest_info.yml
           when:
             - unattend_install_conf is defined
             - unattend_install_conf | lower is not match('.*bclinux-for-euler.*')
+            - vmtools_is_running
 
         - name: "Collect cloud-init logs"
           include_tasks: ../utils/collect_cloudinit_logs.yml
@@ -23,12 +34,7 @@
             - guestinfo_guest_id is defined
             - ((guestinfo_guest_id is match('ubuntu.*') and
                 unattend_install_conf is defined and
-                (unattend_install_conf is match('Ubuntu/Server/') or unattend_install_conf is match('Ubuntu/Desktop/Subiquity'))) or
+                (unattend_install_conf is match('Ubuntu/Server/') or
+                 unattend_install_conf is match('Ubuntu/Desktop/Subiquity'))) or
                (ova_guest_os_type is defined and
                 ova_guest_os_type in ['photon', 'ubuntu', 'amazon']))
-      when:
-        - vm_power_state_get is defined
-        - vm_power_state_get == "poweredOn"
-  when:
-    - vm_exists is defined
-    - vm_exists
diff --git a/linux/deploy_vm/deploy_vm_from_iso.yml b/linux/deploy_vm/deploy_vm_from_iso.yml
index 2c176ca0f..2e9dfd9fa 100644
--- a/linux/deploy_vm/deploy_vm_from_iso.yml
+++ b/linux/deploy_vm/deploy_vm_from_iso.yml
@@ -244,30 +244,12 @@
         boot_order_list: ['disk']
       when: guest_id is match('ubuntu.*')
 
-    - name: "Download serial output file before removing serial port"
-      include_tasks: ../../common/esxi_download_datastore_file.yml
-      vars:
-        src_datastore: "{{ datastore }}"
-        src_file_path: "{{ vm_dir_name }}/{{ vm_serial_port_output_file | basename }}"
-        dest_file_path: "{{ current_test_log_folder }}/{{ vm_serial_port_output_file | basename }}"
-        download_file_fail_ignore: true
-      when:
-        - vm_dir_name is defined
-        - vm_dir_name
-        - vm_serial_port_output_file is defined
-        - vm_serial_port_output_file
+    - name: "Collect serial port log before removing serial port"
+      include_tasks: collect_serial_port_log.yml
 
     - name: "Remove serial port"
       include_tasks: ../../common/vm_remove_serial_port.yml
 
-    - name: "Failed to remove serial port"
-      ansible.builtin.fail:
-        msg: "Failed to remove serial port from VM"
-      when: >
-        remove_serial_port is undefined or
-        remove_serial_port.changed is undefined or
-        not remove_serial_port.changed
-
     - name: "OS auto install is completed. Power on VM now"
       include_tasks: ../../common/vm_set_power_state.yml
       vars:
@@ -367,8 +349,10 @@
                   Oracle Linux 9.0 UEK R7 upgrading failed. Before upgrade, the UEK R7
                   version is '{{ ol9_uekr7_before_upgrade }}', after upgrade the UEK R7
                   version is '{{ ol9_uekr7_after_upgrade }}'.
-
   rescue:
+    - name: "Collect serial port log at test failure"
+      include_tasks: collect_serial_port_log.yml
+
     - name: "Test case failure"
       include_tasks: ../../common/test_rescue.yml
       vars:
diff --git a/linux/deploy_vm/deploy_vm_from_ova.yml b/linux/deploy_vm/deploy_vm_from_ova.yml
index 8ffc3ece1..35bf3a9b7 100644
--- a/linux/deploy_vm/deploy_vm_from_ova.yml
+++ b/linux/deploy_vm/deploy_vm_from_ova.yml
@@ -18,15 +18,16 @@
 
     # OVA file on NFS server
     - name: "Get OVA path and file name after mounting NFS storage at local"
+      when: ova_nfs_server_path is defined and ova_nfs_server_path
       block:
-        - include_tasks: ../../common/mount_nfs_storage_local.yml
+        - name: "Mount NFS storage at local"
+          include_tasks: ../../common/mount_nfs_storage_local.yml
           vars:
             nfs_server_path: "{{ ova_nfs_server_path }}"
         - name: "Get OVA path and file name"
           ansible.builtin.set_fact:
             vm_ova_path: "{{ nfs_mount_dir }}/{{ ova_path }}"
             vm_ova_name: "{{ ova_path | basename }}"
-      when: ova_nfs_server_path is defined and ova_nfs_server_path
     # Check OVA file exists
     - name: "Check for {{ vm_ova_path }} existence"
       ansible.builtin.stat:
@@ -60,7 +61,7 @@
       include_tasks: "../../common/collect_ovf_vm_config.yml"
       vars:
         ovf_vm_hardware_config_path: "{{ current_test_log_folder }}"
-    
+
     - name: "Get VM info"
       include_tasks: ../../common/vm_get_vm_info.yml
 
@@ -87,16 +88,17 @@
         - (hardware_version == "latest" or
            (vm_hardware_version_num | int < hardware_version | int))
 
-    - name: "Get VM info"
-      include_tasks: ../../common/vm_get_vm_info.yml
+    # Add serial port for collecting messages
+    - name: "Add a serial port for VM"
+      include_tasks: ../../common/vm_add_serial_port.yml
 
     - name: "Reconfigure VM with cloud-init"
       include_tasks: reconfigure_vm_with_cloudinit.yml
       when: ova_guest_os_type in ['photon', 'ubuntu', 'amazon']
 
-    - name: "Reconfigure Flatcar VM with Ignition"
-      include_tasks: flatcar/reconfigure_flatcar_vm.yml
-      when: ova_guest_os_type == 'flatcar'
+    - name: "Reconfigure VM with Ignition"
+      include_tasks: reconfigure_vm_with_ignition.yml
+      when: ova_guest_os_type in ['flatcar', 'rhcos']
 
     - name: "Warning about unknown guest OS type"
       ansible.builtin.debug:
@@ -104,13 +106,57 @@
           WARNING: The guest OS type of the OVA doesn't match known guest OS type for
           reconfiguration. Please add it if needed or the following tests might fail.
       when: ova_guest_os_type == 'unknown'
+
+    - name: "Collect VM deployment logs"
+      include_tasks: collect_vm_logs.yml
+
+    - name: "Shutdown guest OS"
+      include_tasks: ../utils/shutdown.yml
+
+    - name: "Collect serial port log before removing serial port"
+      include_tasks: collect_serial_port_log.yml
+
+    - name: "Remove serial port from VM"
+      include_tasks: ../../common/vm_remove_serial_port.yml
+
+    # The workaround "Remove CDROM" for issue: https://bugs.launchpad.net/cloud-init/+bug/1992509
+    - name: "Remove existing CDROMs"
+      include_tasks: ../../common/vm_configure_cdrom.yml
+      vars:
+        cdrom_type: client
+        cdrom_controller_type: "{{ vm_cdrom.controller_label.split()[0] | lower }}"
+        cdrom_controller_num: "{{ vm_cdrom.bus_num }}"
+        cdrom_unit_num: "{{ vm_cdrom.unit_num }}"
+        cdrom_state: absent
+      with_items: "{{ vm_existing_cdrom_list }}"
+      loop_control:
+        loop_var: vm_cdrom
+      when:
+        - guest_os_ansible_distribution == "Ubuntu"
+        - vm_existing_cdrom_list is defined
+        - vm_existing_cdrom_list | length > 0
+
+    - name: "Power on VM"
+      include_tasks: ../../common/vm_set_power_state.yml
+      vars:
+        vm_power_state_set: 'powered-on'
   rescue:
+    # If test case failed before collecting VM cloud-init logs,
+    # the logs need to be collected at rescue
+    - name: "Collect VM deployment logs"
+      include_tasks: collect_vm_logs.yml
+      when: cloudinit_logs_local_path is undefined
+
+    - name: "Collect serial port log at test failure"
+      include_tasks: collect_serial_port_log.yml
+
     - name: "Test case failure"
       include_tasks: ../../common/test_rescue.yml
       vars:
         exit_testing_when_fail: true
   always:
     - name: "Unmount NFS share folder and remove mount folder"
+      when: nfs_mount_dir is defined and nfs_mount_dir
       block:
         - name: "Umount NFS share points"
           include_tasks: ../../common/local_unmount.yml
@@ -124,7 +170,3 @@
           vars:
             local_path: "{{ nfs_mount_dir }}"
             del_local_file_ignore_errors: true
-      when: nfs_mount_dir is defined and nfs_mount_dir
-
-    - name: "Collect VM deployment logs"
-      include_tasks: collect_vm_logs.yml
diff --git a/linux/deploy_vm/flatcar/flatcar_post_config.yml b/linux/deploy_vm/flatcar/flatcar_post_config.yml
index 6c957f8a3..fe6303b31 100644
--- a/linux/deploy_vm/flatcar/flatcar_post_config.yml
+++ b/linux/deploy_vm/flatcar/flatcar_post_config.yml
@@ -15,32 +15,16 @@
   vars:
     guest_file_path: "/etc/ssh/sshd_config"
 
-# If /etc/ssh/sshd_config is a symbolic link
-# it means the file has not been changed
-- name: "Permit root login through ssh"
-  block:
-    - name: "Convert /etc/ssh/sshd_config from symbolic link to regular file"
-      ansible.builtin.shell: sed -i '' /etc/ssh/sshd_config
-      become: true
-      delegate_to: "{{ vm_guest_ip }}"
-
-    - include_tasks: ../../utils/replace_or_add_line_in_file.yml
-      vars:
-        file: "/etc/ssh/sshd_config"
-        reg_exp: "^#?PermitRootLogin"
-        line_content: "PermitRootLogin yes"
+# The original /etc/ssh/sshd_config on Flatcar is a symbolic link
+- name: "Convert /etc/ssh/sshd_config from symbolic link to regular file"
+  ansible.builtin.shell: sed -i '' /etc/ssh/sshd_config
+  become: true
+  delegate_to: "{{ vm_guest_ip }}"
   when: guest_file_stat.islnk | default(false)
 
-# Change user password
-- name: "Get user names for password changing"
-  ansible.builtin.set_fact:
-    usernames: "{{ [vm_username] | union(['core']) }}"
-
-- name: "Change password for user {{ vm_username }}"
-  ansible.builtin.user:
-    name: "{{ username }}"
-    password: "{{ vm_password | password_hash('sha512') }}"
-  delegate_to: "{{ vm_guest_ip }}"
-  with_items: "{{ usernames }}"
-  loop_control:
-    loop_var: username
+- name: "Permit root login through ssh"
+  include_tasks: ../../utils/replace_or_add_line_in_file.yml
+  vars:
+    file: "/etc/ssh/sshd_config"
+    reg_exp: "^#?PermitRootLogin"
+    line_content: "PermitRootLogin yes"
diff --git a/linux/deploy_vm/flatcar/generate_ignition_config.yml b/linux/deploy_vm/flatcar/generate_ignition_config.yml
deleted file mode 100644
index eae83f011..000000000
--- a/linux/deploy_vm/flatcar/generate_ignition_config.yml
+++ /dev/null
@@ -1,44 +0,0 @@
-# Copyright 2021-2023 VMware, Inc.
-# SPDX-License-Identifier: BSD-2-Clause
----
-# Generate ignition_config.json file and its base64 encoding
-# Parameters: None
-# Return: ignition_config_data
-- name: "Create a temporary file as Ignition config file"
-  include_tasks: ../../../common/create_temp_file_dir.yml
-  vars:
-    tmp_state: "file"
-    tmp_prefix: "ignition_"
-    tmp_suffix: ".json"
-
-- name: "Set variables for Ignition config"
-  ansible.builtin.set_fact:
-    ignition_config_file: "{{ tmp_path }}"
-
-# Put SSH public key into ignition config file
-- name: "Generation ignition config file {{ ignition_config_file }}"
-  ansible.builtin.template:
-    src: ignition_config.j2
-    dest: "{{ ignition_config_file }}"
-    mode: "0644"
-  register: generate_ignition
-
-- name: "Assert {{ ignition_config_file }} is generated"
-  ansible.builtin.assert:
-    that:
-      - generate_ignition.changed
-    fail_msg: "Failed to generate {{ ignition_config_file }}"
-    success_msg: "Successfully generated {{ ignition_config_file }}"
-
-- block:
-    - name: "Generate base64 encoded string for {{ ignition_config_file }}"
-      ansible.builtin.set_fact:
-        ignition_config_data: "{{ lookup('file', ignition_config_file) | b64encode }}"
-
-    - ansible.builtin.debug: var=ignition_config_data
-
-    - name: "Remove {{ ignition_config_file }}"
-      include_tasks: ../../../common/delete_local_file.yml
-      vars:
-        local_path: "{{ ignition_config_file }}"
-  when: generate_ignition.changed
diff --git a/linux/deploy_vm/flatcar/ignition_config.j2 b/linux/deploy_vm/flatcar/ignition_config.j2
deleted file mode 100644
index d6a41d9f9..000000000
--- a/linux/deploy_vm/flatcar/ignition_config.j2
+++ /dev/null
@@ -1,39 +0,0 @@
-{
-  "ignition": {
-    "config": {},
-    "timeouts": {},
-    "version": "2.1.0"
-  },
-  "passwd": {
-    "users": [
-     {
-        "name": "{{ vm_username }}",
-        "sshAuthorizedKeys": [
-          "{{ ssh_public_key }}"
-        ]
-     {% if new_user is defined and new_user != 'root' and new_user != 'core' %}
-     },
-     {
-        "name": "{{ new_user }}",
-        "passwordHash": "{{ vm_password_hash }}",
-        "sshAuthorizedKeys": [
-          "{{ ssh_public_key }}"
-        ]
-     {% endif %}
-     }
-    ]
-  },
-  "systemd": {
-    "units":[{
-      "name": "update-engine.service",
-      "enabled": false,
-      "mask": true
-    },
-    {
-      "name": "locksmithd.service",
-      "enabled": false,
-      "mask": true
-    }]
-  },
-  "storage": {}
-}
diff --git a/linux/deploy_vm/flatcar/reconfigure_flatcar_vm.yml b/linux/deploy_vm/flatcar/reconfigure_flatcar_vm.yml
deleted file mode 100644
index be16c3267..000000000
--- a/linux/deploy_vm/flatcar/reconfigure_flatcar_vm.yml
+++ /dev/null
@@ -1,53 +0,0 @@
-# Copyright 2021-2023 VMware, Inc.
-# SPDX-License-Identifier: BSD-2-Clause
----
-# Use Ignition to configure ssh authorized key and user password
-- name: "Generate Ignition config file"
-  include_tasks: generate_ignition_config.yml
-
-- name: "Defining the Ignition configs in Guestinfo"
-  include_tasks: ../../../common/vm_set_extra_config.yml
-  vars:
-    vm_advanced_settings:
-      - key: "guestinfo.coreos.config.data"
-        value: "{{ ignition_config_data }}"
-      - key: "guestinfo.coreos.config.data.encoding"
-        value: "base64"
-
-- name: "Power on VM"
-  include_tasks: ../../common/vm_set_power_state.yml
-  vars:
-    vm_power_state_set: 'powered-on'
-
-- name: "Get VM's extra config"
-  include_tasks: ../../common/vm_get_extra_config.yml
-
-- name: "Check Ignition configs is present in VM's extra config after VM power-on"
-  ansible.builtin.assert:
-    that:
-      - vm_extra_config['guestinfo.coreos.config.data'] is defined
-      - vm_extra_config['guestinfo.coreos.config.data'] == ignition_config_data
-      - vm_extra_config['guestinfo.coreos.config.data.encoding'] is defined
-      - vm_extra_config['guestinfo.coreos.config.data.encoding'] == 'base64'
-    fail_msg: >-
-      The Ignition configs are not correct in VM's extra config after VM power-on. In VM's extra config,
-      guestinfo.coreos.config.data = {{ vm_extra_config['guestinfo.coreos.config.data'] | default('') }},
-      guestinfo.coreos.config.data.encoding = {{ vm_extra_config['guestinfo.coreos.config.data.encoding'] |
-                                                default('') }}.
-
-# Skip checking guest full name here because we will check it in TD1 case
-- include_tasks: ../../../common/vm_wait_guest_fullname.yml
-
-# Set vm_python to auto
-- name: "Reset vm_python to auto"
-  ansible.builtin.set_fact:
-    vm_python: "auto"
-  when: vm_python is defined and vm_python != "auto"
-
-# Get guest ip
-- include_tasks: ../../../common/update_inventory.yml
-  vars:
-    update_inventory_timeout: 300
-
-# Post configuration for ssh, cloud-init and vmtools
-- include_tasks: flatcar_post_config.yml
diff --git a/linux/deploy_vm/generate_ignition_config.yml b/linux/deploy_vm/generate_ignition_config.yml
new file mode 100644
index 000000000..045cb1753
--- /dev/null
+++ b/linux/deploy_vm/generate_ignition_config.yml
@@ -0,0 +1,33 @@
+# Copyright 2021-2023 VMware, Inc.
+# SPDX-License-Identifier: BSD-2-Clause
+---
+# Generate ignition_config.json file and its base64 encoding
+# Return:
+#   ignition_config_data: The Ignition config data encoded in base64
+#
+- name: "Set fact of Ignition config file path"
+  ansible.builtin.set_fact:
+    ignition_config_file: "{{ current_test_log_folder }}/ignition.json"
+    ignition_sshd_config: "{{ 'PermitRootLogin yes\nPasswordAuthentication yes\n' | b64encode }}"
+
+# Put SSH public key into ignition config file
+- name: "Generation Ignition config file {{ ignition_config_file }}"
+  ansible.builtin.template:
+    src: "templates/ignition_config.j2"
+    dest: "{{ ignition_config_file }}"
+    mode: "0644"
+  register: generate_ignition
+
+- name: "Assert Ignition config file is generated"
+  ansible.builtin.assert:
+    that:
+      - generate_ignition.changed
+    fail_msg: "Failed to generate {{ ignition_config_file }}"
+    success_msg: "Successfully generated {{ ignition_config_file }}"
+
+- name: "Generate base64 encoded data for {{ ignition_config_file }}"
+  ansible.builtin.set_fact:
+    ignition_config_data: "{{ lookup('file', ignition_config_file) | b64encode }}"
+
+- name: "Display base64 encoded data of Ignition config file {{ ignition_config_file }}"
+  ansible.builtin.debug: var=ignition_config_data
diff --git a/linux/deploy_vm/get_ova_guest_os_type.yml b/linux/deploy_vm/get_ova_guest_os_type.yml
index da1c1e778..9ab6bac77 100644
--- a/linux/deploy_vm/get_ova_guest_os_type.yml
+++ b/linux/deploy_vm/get_ova_guest_os_type.yml
@@ -8,6 +8,7 @@
       {%- if 'ubuntu' in vm_guest_id -%}ubuntu
       {%- elif 'amazonlinux' in vm_guest_id -%}amazon
       {%- elif 'vmwarePhoton' in vm_guest_id -%}photon
+      {%- elif 'coreos' in vm_guest_id or 'rhel' in vm_guest_id -%}rhcos
       {%- else -%}unknown{%- endif -%}
 
 # Try to get the OS type from guest id
@@ -17,6 +18,7 @@
       {%- if 'ubuntu' in guestinfo_guest_id -%}ubuntu
       {%- elif 'amazonlinux' in guestinfo_guest_id -%}amazon
       {%- elif 'vmwarePhoton' in guestinfo_guest_id -%}photon
+      {%- elif 'coreos' in guestinfo_guest_id or 'rhel' in guestinfo_guest_id -%}rhcos
       {%- else -%}unknown{%- endif -%}
   when:
     - ova_guest_os_type == 'unknown'
@@ -31,6 +33,8 @@
       {%- elif 'amazon linux' in guestinfo_guest_full_name | lower -%}amazon
       {%- elif 'vmware photon' in guestinfo_guest_full_name | lower -%}photon
       {%- elif 'flatcar' in guestinfo_guest_full_name | lower -%}flatcar
+      {%- elif 'coreos' in guestinfo_guest_full_name | lower -%}rhcos
+      {%- elif 'Red Hat Enterprise Linux' in guestinfo_guest_full_name -%}rhcos
       {%- else -%}unknown{%- endif -%}
   when:
     - ova_guest_os_type == 'unknown'
@@ -44,6 +48,7 @@
       {%- elif 'Amazon Linux' in guestinfo_detailed_data -%}amazon
       {%- elif 'VMware Photon OS' in guestinfo_detailed_data -%}photon
       {%- elif 'Flatcar' in guestinfo_detailed_data -%}flatcar
+      {%- elif 'CoreOS' in guestinfo_detailed_data -%}rhcos
       {%- else -%}unknown{%- endif -%}
   when:
     - ova_guest_os_type == 'unknown'
diff --git a/linux/deploy_vm/reconfigure_vm_with_cloudinit.yml b/linux/deploy_vm/reconfigure_vm_with_cloudinit.yml
index 21ba76c6d..354e08211 100644
--- a/linux/deploy_vm/reconfigure_vm_with_cloudinit.yml
+++ b/linux/deploy_vm/reconfigure_vm_with_cloudinit.yml
@@ -3,23 +3,35 @@
 ---
 - name: "Set fact of cloud-init final message"
   ansible.builtin.set_fact:
-    cloudinit_final_msg: "The system is finally up, after $UPTIME seconds"
-
-# Add serial port for Ubuntu OVA when hardware_version > 10.
-# Otherwise, it would hang at boot time
-- name: "Add serial port for Ubuntu VM deployed from OVA"
-  include_tasks: ../../common/vm_add_serial_port.yml
-  when:
-    - ova_guest_os_type == 'ubuntu'
-    - vm_hardware_version_num is defined
-    - vm_hardware_version_num | int > 10
+    cloudinit_final_msg: "OVA deployment with cloud-init config is completed"
+    cloudinit_runcmd:
+      - echo 'Get OS release info' >/dev/ttyS0
+      - cat /etc/os-release >/dev/ttyS0
+      - echo 'Update sshd settings in cloud-init config' >/dev/ttyS0
+      - [sed, -i, 's/^disable_root:.*/disable_root: false/', /etc/cloud/cloud.cfg]
+      - [sed, -i, 's/^ssh_pwauth:.*/ssh_pwauth: true/', /etc/cloud/cloud.cfg]
+      - echo 'Update sshd config to permit root login and password authentication' >/dev/ttyS0
+      - [sed, -i, 's/^#*PermitRootLogin .*/PermitRootLogin yes/', /etc/ssh/sshd_config]
+      - [sed, -i, 's/^#*PasswordAuthentication .*/PasswordAuthentication yes/', /etc/ssh/sshd_config]
+
+- name: "Update cloud-init runcmd for {{ ova_guest_os_type | capitalize }}"
+  ansible.builtin.set_fact:
+    cloudinit_runcmd: >-
+      {{
+        cloudinit_runcmd |
+        union(["echo 'Restart sshd service' >/dev/ttyS0",
+               "systemctl restart sshd",
+               "echo 'Get sshd service status' >/dev/ttyS0",
+               "systemctl status sshd >/dev/ttyS0"
+              ])
+      }}
+  when: ova_guest_os_type in ['amazon', 'ubuntu']
 
 - name: "Create cloud-init seed ISO to configure guest OS"
   include_tasks: ../utils/create_seed_iso.yml
   vars:
     user_data_template: "{{ ova_guest_os_type }}-ova-user-data.j2"
     local_hostname: "{{ ova_guest_os_type }}-ova-{{ hostname_timestamp }}"
-    mode: '0644'
 
 - name: "Upload cloud-init seed ISO to ESXi server datastore"
   include_tasks: ../../common/esxi_upload_datastore_file.yml
@@ -137,44 +149,3 @@
   when:
     - cdrom_device_list is defined
     - cdrom_device_list | length > 0
-
-- name: "Remove serial port from Ubuntu VM"
-  block:
-    - name: "Shutdown guest OS"
-      include_tasks: ../utils/shutdown.yml
-
-    - name: "Remove serial port from VM"
-      include_tasks: ../../common/vm_remove_serial_port.yml
-
-    - name: "Failed to remove serial port from VM"
-      ansible.builtin.fail:
-        msg: "Failed to remove serial port from VM"
-      when: >
-        remove_serial_port is undefined or
-        remove_serial_port.changed is undefined or
-        not remove_serial_port.changed
-
-    # The workaround "Remove CDROM" for issue: https://bugs.launchpad.net/cloud-init/+bug/1992509
-    - name: "Remove all CDROM"
-      include_tasks: ../../common/vm_configure_cdrom.yml
-      vars:
-        cdrom_type: client
-        cdrom_controller_type: "{{ vm_cdrom.controller_label.split()[0] | lower }}"
-        cdrom_controller_num: "{{ vm_cdrom.bus_num }}"
-        cdrom_unit_num: "{{ vm_cdrom.unit_num }}"
-        cdrom_state: absent
-      with_items: "{{ vm_existing_cdrom_list }}"
-      loop_control:
-        loop_var: vm_cdrom
-      when: vm_existing_cdrom_list | length > 0
-
-    - name: "Power on VM"
-      include_tasks: ../../common/vm_set_power_state.yml
-      vars:
-        vm_power_state_set: 'powered-on'
-  when:
-    - ova_guest_os_type == 'ubuntu'
-    - vm_hardware_version_num is defined
-    - vm_hardware_version_num | int > 10
-    - vm_serial_port_file_path is defined
-    - vm_serial_port_file_path
diff --git a/linux/deploy_vm/reconfigure_vm_with_ignition.yml b/linux/deploy_vm/reconfigure_vm_with_ignition.yml
new file mode 100644
index 000000000..07c393e97
--- /dev/null
+++ b/linux/deploy_vm/reconfigure_vm_with_ignition.yml
@@ -0,0 +1,46 @@
+# Copyright 2023 VMware, Inc.
+# SPDX-License-Identifier: BSD-2-Clause
+---
+# Use Ignition to configure guest OS username, password, SSH authorized keys, etc
+#
+- name: "Generate Ignition config file"
+  include_tasks: generate_ignition_config.yml
+
+- name: "Define Ignition configs in VM guestinfo"
+  include_tasks: ../../common/vm_set_extra_config.yml
+  vars:
+    vm_advanced_settings:
+      - key: "guestinfo.ignition.config.data"
+        value: "{{ ignition_config_data }}"
+      - key: "guestinfo.ignition.config.data.encoding"
+        value: "base64"
+
+- name: "Power on VM"
+  include_tasks: ../../common/vm_set_power_state.yml
+  vars:
+    vm_power_state_set: 'powered-on'
+
+- name: "Get VM's extra config"
+  include_tasks: ../../common/vm_get_extra_config.yml
+
+- name: "Wait for guest full name is collected by VMware Tools"
+  include_tasks: ../../common/vm_wait_guest_fullname.yml
+
+# Set vm_python to auto
+- name: "Reset vm_python to auto"
+  ansible.builtin.set_fact:
+    vm_python: "auto"
+  when: vm_python is defined and vm_python != "auto"
+
+# Get guest ip
+- name: "Get VM's guest IP address and add it to in-memory inventory"
+  include_tasks: ../../common/update_inventory.yml
+  vars:
+    update_inventory_timeout: 300
+
+- name: "Post config on Flatcar"
+  include_tasks: flatcar/flatcar_post_config.yml
+  when: ova_guest_os_type == "flatcar"
+
+- name: "Retrieve Linux guest system info"
+  include_tasks: ../utils/get_linux_system_info.yml
diff --git a/linux/deploy_vm/templates/amazon-ova-user-data.j2 b/linux/deploy_vm/templates/amazon-ova-user-data.j2
index 642dd11a2..339f928f7 100644
--- a/linux/deploy_vm/templates/amazon-ova-user-data.j2
+++ b/linux/deploy_vm/templates/amazon-ova-user-data.j2
@@ -19,10 +19,11 @@ users:
 {% endif %}
 
 runcmd:
-  - [ sed, -i, "s/^#PermitRootLogin .*/PermitRootLogin yes/", "/etc/ssh/sshd_config"]
-  - [ sed, -i, "s/^disable_root:.*/disable_root: false/", "/etc/cloud/cloud.cfg"]
-  - [ sed, -i, "s/^ssh_pwauth:.*/ssh_pwauth: true/", "/etc/cloud/cloud.cfg"]
-  - [ sed, -i, "s/^repo_upgrade:.*/repo_upgrade: none/", "/etc/cloud/cloud.cfg"]
+{% for cmd in cloudinit_runcmd %}
+  - {{ cmd }}
+{% endfor %}
+  - echo 'Disable repo upgrade in cloud-init config' >/dev/ttyS0
+  - [sed, -i, 's/^repo_upgrade:.*/repo_upgrade: none/', /etc/cloud/cloud.cfg]
 
 write_files:
   - content: |
diff --git a/linux/deploy_vm/templates/ignition_config.j2 b/linux/deploy_vm/templates/ignition_config.j2
new file mode 100644
index 000000000..26c6a38d8
--- /dev/null
+++ b/linux/deploy_vm/templates/ignition_config.j2
@@ -0,0 +1,65 @@
+{
+    "ignition": {
+{% if ova_guest_os_type is defined and ova_guest_os_type == 'flatcar' %}
+        "version": "2.1.0"
+{% else %}
+        "version": "3.3.0"
+{% endif %}
+    },
+    "passwd": {
+        "users": [
+            {
+                "name": "core",
+                "passwordHash": "{{ vm_password_hash }}",
+                "sshAuthorizedKeys": [
+                  "{{ ssh_public_key }}"
+                ]
+             },
+             {
+                "name": "{{ vm_username }}",
+                "passwordHash": "{{ vm_password_hash }}",
+                "sshAuthorizedKeys": [
+                  "{{ ssh_public_key }}"
+                ]
+             }
+             {% if new_user is defined and new_user != 'root' and new_user != 'core' %}
+             ,{
+                "name": "{{ new_user }}",
+                "passwordHash": "{{ vm_password_hash }}",
+                "sshAuthorizedKeys": [
+                  "{{ ssh_public_key }}"
+                ]
+             }
+             {% endif %}
+        ]
+    },
+{% if ova_guest_os_type is defined and ova_guest_os_type == 'flatcar' %}
+    "systemd": {
+        "units": [
+            {
+              "name": "update-engine.service",
+              "enabled": false,
+              "mask": true
+            },
+            {
+              "name": "locksmithd.service",
+              "enabled": false,
+              "mask": true
+            }
+        ]
+    },
+{% endif %}
+   "storage": {
+{% if ova_guest_os_type is defined and ova_guest_os_type == 'rhcos' %}
+       "files": [
+            {
+                "contents": {
+                    "source": "data:text/plain;charset=utf-8;base64,{{ ignition_sshd_config }}"
+                },
+                "mode": 644,
+                "path": "/etc/ssh/sshd_config.d/00_permit_root.conf"
+            }
+        ]
+{% endif %}
+   }
+}
diff --git a/linux/deploy_vm/templates/photon-ova-user-data.j2 b/linux/deploy_vm/templates/photon-ova-user-data.j2
index 5ae08c055..62d6ec61c 100644
--- a/linux/deploy_vm/templates/photon-ova-user-data.j2
+++ b/linux/deploy_vm/templates/photon-ova-user-data.j2
@@ -29,13 +29,16 @@ users:
 
 # Workaround for root password setting when shadow version is 4.6-5 and earlier
 bootcmd:
-  - shadow_version=$(rpm -q shadow | grep -E -o "[0-9]+(\.[0-9]+)+-[0-9]+"); [ $(printf "$shadow_version\n4.6-6\n" | sort | head -n 1) != "4.6-6" ] && /bin/sed -E -i 's/^root:([^:]+):.*$/root:\1:17532:0:99999:0:::/' /etc/shadow
+  - echo "Running cloud-init bootcmd" >/dev/ttyS0
+  - shadow_version=$(rpm -q shadow | grep -E -o "[0-9]+(\.[0-9]+)+-[0-9]+"); echo "Shadow version is $shadow_version" >/dev/ttyS0; [ $(printf "$shadow_version\n4.6-6\n" | sort | head -n 1) != "4.6-6" ] && /bin/sed -E -i 's/^root:([^:]+):.*$/root:\1:17532:0:99999:0:::/' /etc/shadow
 
 runcmd:
+{% for cmd in cloudinit_runcmd %}
+  - {{ cmd }}
+{% endfor %}
+  - echo "Stop and disable iptables" >/dev/ttyS0
   - [systemctl, stop, iptables]
   - [systemctl, disable, iptables]
-  - [systemctl, disable, chronyd]
-  - [systemctl, disable, chrony-wait]
-  - os_version=$(grep VERSION= /etc/os-release | grep -E -o "[0-9]+\.[0-9]+"); [ $(printf "$os_version\n4.0\n" | sort | head -n 1 | cut -d '.' -f 1) -ge 4 ] && systemctl start sshd.socket
+  - os_major_ver=$(grep VERSION= /etc/os-release | grep -Eo "[0-9]+\.[0-9]+" | cut -d '.' -f 1); [ $os_major_ver -ge 4 ] && (echo "Starting sshd.socket ..." >/dev/ttyS0; systemctl start sshd.socket; systemctl status sshd.socket >/dev/ttyS0)
 
 final_message: "{{ cloudinit_final_msg }}"
diff --git a/linux/deploy_vm/templates/ubuntu-ova-user-data.j2 b/linux/deploy_vm/templates/ubuntu-ova-user-data.j2
index 9567372b5..f8d9bbf8e 100644
--- a/linux/deploy_vm/templates/ubuntu-ova-user-data.j2
+++ b/linux/deploy_vm/templates/ubuntu-ova-user-data.j2
@@ -20,9 +20,12 @@ packages:
   - net-tools
   - sg3-utils
   - ndctl
+
 runcmd:
+{% for cmd in cloudinit_runcmd %}
+  - {{ cmd }}
+{% endfor %}
+  - echo 'Force apt-get to use IPv4 address' >/dev/ttyS0
   - echo 'Acquire::ForceIPv4 "true";' >>/etc/apt/apt.conf.d/99force-ipv4
-  - sed -i 's/^#*PermitRootLogin .*/PermitRootLogin yes/' /etc/ssh/sshd_config
-  - systemctl restart sshd
 
 final_message: "{{ cloudinit_final_msg }}"
diff --git a/linux/deploy_vm/upgrade_ova_vm_hwv.yml b/linux/deploy_vm/upgrade_ova_vm_hwv.yml
index d91e61fe9..f8f138926 100644
--- a/linux/deploy_vm/upgrade_ova_vm_hwv.yml
+++ b/linux/deploy_vm/upgrade_ova_vm_hwv.yml
@@ -5,14 +5,11 @@
   vars:
     hw_version: "{{ hardware_version }}"
 
-- name: "Reset VM hardware version to the upgraded version"
-  ansible.builtin.set_fact:
-    vm_hardware_version_num: "{{ vm_upgrade_hw_result.instance.hw_version.split('-')[1] }}"
-
 - name: "Set fact of the base snapshot name"
   ansible.builtin.set_fact:
     base_snapshot_for_reconfig: "AfterUpgradeHwv"
 
-- include_tasks: ../../common/vm_take_snapshot.yml
+- name: "Take a new snapshot after upgrading hardware version"
+  include_tasks: ../../common/vm_take_snapshot.yml
   vars:
     snapshot_name: "{{ base_snapshot_for_reconfig }}"
diff --git a/linux/guest_customization/check_gosc_support_status.yml b/linux/guest_customization/check_gosc_support_status.yml
index 204aec1ca..846256388 100644
--- a/linux/guest_customization/check_gosc_support_status.yml
+++ b/linux/guest_customization/check_gosc_support_status.yml
@@ -44,14 +44,19 @@
 
     - name: "Set default guest OS list not support GOSC"
       ansible.builtin.set_fact:
-        gos_not_support_gosc: ["FreeBSD", "SLED", "Astra Linux (Orel)", "Fedora", "openSUSE Leap"]
+        gos_not_support_gosc:
+           - "Flatcar"
+           - "SLED"
+           - "FreeBSD"
+           - "Astra Linux (Orel)"
+           - "Fedora"
+           - "openSUSE Leap"
+           - "RHCOS"
 
     - name: "Set fact of GOSC support status to False for {{ guest_os_ansible_distribution }}"
       ansible.builtin.set_fact:
         gosc_is_supported: false
-      when: >
-        (guest_os_ansible_distribution in gos_not_support_gosc) or
-        (guest_os_ansible_distribution == 'Flatcar')
+      when: guest_os_ansible_distribution in gos_not_support_gosc
 
     - name: "Set cloud-init GOSC support status for {{ vm_guest_os_distribution }}"
       block:
@@ -126,7 +131,6 @@
       when:
         - not enable_cloudinit_gosc | bool
         - guest_os_ansible_distribution not in gos_not_support_gosc
-        - guest_os_ansible_distribution != 'Flatcar'
 
     - name: "Display GOSC support status for {{ vm_guest_os_distribution }}"
       ansible.builtin.debug:
diff --git a/linux/network_device_ops/check_pvrdma_support_status.yml b/linux/network_device_ops/check_pvrdma_support_status.yml
index 96617fe14..dff8deaf6 100644
--- a/linux/network_device_ops/check_pvrdma_support_status.yml
+++ b/linux/network_device_ops/check_pvrdma_support_status.yml
@@ -8,7 +8,7 @@
   vars:
     skip_msg: "{{ guest_os_ansible_distribution }} doesn't support PVRDMA"
     skip_reason: "Not Supported"
-  when: guest_os_ansible_distribution in ['Fedora', 'VMware Photon OS', 'Flatcar', 'FreeBSD']
+  when: guest_os_ansible_distribution in ['Fedora', 'VMware Photon OS', 'Flatcar', 'FreeBSD', 'RHCOS']
 
 - name: "Get guest config options"
   include_tasks: ../../common/esxi_get_guest_config_options.yml
diff --git a/linux/nvdimm_cold_add_remove/nvdimm_cold_add_remove.yml b/linux/nvdimm_cold_add_remove/nvdimm_cold_add_remove.yml
index bf82154be..b2ec2daa2 100644
--- a/linux/nvdimm_cold_add_remove/nvdimm_cold_add_remove.yml
+++ b/linux/nvdimm_cold_add_remove/nvdimm_cold_add_remove.yml
@@ -25,7 +25,8 @@
               doesn't support NVDIMM.
             skip_reason: "Not Supported"
           when: >
-             (guest_os_ansible_distribution in ['Flatcar', 'UnionTech', 'Uos', 'Amazon', 'openSUSE Leap', 'FreeBSD'] or
+             (guest_os_ansible_distribution in ['Flatcar', 'UnionTech', 'Uos', 'Amazon',
+                                                'openSUSE Leap', 'FreeBSD', 'RHCOS'] or
              (guest_os_ansible_distribution == 'Ubuntu' and
               guest_os_edition == 'CloudImage'))
 
diff --git a/linux/open_vm_tools/ovt_verify_install.yml b/linux/open_vm_tools/ovt_verify_install.yml
index b2f7b6b92..043836c47 100644
--- a/linux/open_vm_tools/ovt_verify_install.yml
+++ b/linux/open_vm_tools/ovt_verify_install.yml
@@ -21,12 +21,12 @@
             update_vmtools: true
           when: update_vmtools is undefined
 
-        # Flatcar doesn't support to install open-vm-tools
+        # Flatcar and RHCOS doesn't support to install open-vm-tools
         - include_tasks: ../../common/skip_test_case.yml
           vars:
             skip_msg: "Skip test case because {{ guest_os_ansible_distribution }} doesn't support installing open-vm-tools"
             skip_reason: "Not Supported"
-          when: guest_os_ansible_distribution == 'Flatcar'
+          when: guest_os_ansible_distribution in ['Flatcar', 'RHCOS']
 
         # VM has open-vm-tools installed and update_vmtools is set false
         - include_tasks: ../../common/skip_test_case.yml
diff --git a/linux/open_vm_tools/ovt_verify_uninstall.yml b/linux/open_vm_tools/ovt_verify_uninstall.yml
index e6ff3f492..ead4cf9c9 100644
--- a/linux/open_vm_tools/ovt_verify_uninstall.yml
+++ b/linux/open_vm_tools/ovt_verify_uninstall.yml
@@ -21,7 +21,7 @@
           vars:
             skip_msg: "Skip test case because {{ guest_os_ansible_distribution }} doesn't support uninstalling open-vm-tools"
             skip_reason: "Not Supported"
-          when: guest_os_ansible_distribution == 'Flatcar'
+          when: guest_os_ansible_distribution in ['Flatcar', 'RHCOS']
 
         - name: "Block test case when guest OS doesn't install open-vm-tools"
           include_tasks: ../../common/skip_test_case.yml
diff --git a/linux/utils/create_seed_iso.yml b/linux/utils/create_seed_iso.yml
index 2fb88d1eb..bb265c85a 100644
--- a/linux/utils/create_seed_iso.yml
+++ b/linux/utils/create_seed_iso.yml
@@ -30,7 +30,7 @@
   ansible.builtin.template:
     src: "{{ user_data_template }}"
     dest: "{{ user_data_path }}"
-    mode: "0644"
+    mode: "0666"
   vars:
     vm_password_hash: "{{ vm_password | password_hash('sha512') }}"
 
@@ -38,7 +38,7 @@
   ansible.builtin.file:
     path: "{{ meta_data_path }}"
     state: touch
-    mode: "0644"
+    mode: "0666"
 
 - name: "Set hostname in cloud-init meta-data"
   ansible.builtin.lineinfile:
diff --git a/linux/utils/get_installed_package_info.yml b/linux/utils/get_installed_package_info.yml
index 2e21d6774..4bd2adb16 100644
--- a/linux/utils/get_installed_package_info.yml
+++ b/linux/utils/get_installed_package_info.yml
@@ -16,7 +16,7 @@
 - name: "Get package query command for OS packages managed by {{ guest_os_ansible_pkg_mgr | upper }}"
   ansible.builtin.set_fact:
     package_query_cmd: "rpm -qi"
-  when: guest_os_ansible_pkg_mgr in ['yum', 'dnf', 'zypper']
+  when: guest_os_ansible_pkg_mgr in ['yum', 'dnf', 'zypper', 'atomic_container']
 
 - name: "Get package query command for OS packages managed by {{ guest_os_ansible_pkg_mgr | upper }}"
   ansible.builtin.set_fact:
diff --git a/linux/utils/get_linux_system_info.yml b/linux/utils/get_linux_system_info.yml
index eae4843e4..663dc3401 100644
--- a/linux/utils/get_linux_system_info.yml
+++ b/linux/utils/get_linux_system_info.yml
@@ -9,6 +9,13 @@
 - name: "Get OS release info"
   include_tasks: get_os_release.yml
 
+- name: "Correct guest OS ansible distribution for RHCOS"
+  ansible.builtin.set_fact:
+    guest_os_ansible_distribution: "RHCOS"
+  when:
+    - guest_os_release.ID is defined
+    - guest_os_release.ID == 'rhcos'
+
 - name: "Set fact of guest OS ansible distribution is correct or not"
   ansible.builtin.set_fact:
     guest_os_ansible_distrib_is_correct: >-
diff --git a/linux/vhba_hot_add_remove/vhba_device_hot_add_remove.yml b/linux/vhba_hot_add_remove/vhba_device_hot_add_remove.yml
index 514be4349..526f72c68 100644
--- a/linux/vhba_hot_add_remove/vhba_device_hot_add_remove.yml
+++ b/linux/vhba_hot_add_remove/vhba_device_hot_add_remove.yml
@@ -36,7 +36,7 @@
             package_state: "present"
       when:
         - new_disk_ctrl_type == 'lsilogic'
-        - guest_os_ansible_distribution != 'Flatcar'
+        - guest_os_ansible_distribution not in ['Flatcar', 'RHCOS', 'FreeBSD']
 
     - name: "Get file lsblk.sh for FreeBSD"
       when: guest_os_ansible_distribution == "FreeBSD"
diff --git a/linux/vhba_hot_add_remove/wait_device_list_changed.yml b/linux/vhba_hot_add_remove/wait_device_list_changed.yml
index 6622c62f1..ac59a8ba2 100644
--- a/linux/vhba_hot_add_remove/wait_device_list_changed.yml
+++ b/linux/vhba_hot_add_remove/wait_device_list_changed.yml
@@ -34,7 +34,7 @@
   block:
     - name: "Rescan scsi devices in {{ guest_os_ansible_distribution }} {{ guest_os_ansible_distribution_ver }}"
       when:
-        - guest_os_ansible_distribution not in ['Flatcar', 'Fedora', 'FreeBSD']
+        - guest_os_ansible_distribution not in ['Flatcar', 'Fedora', 'FreeBSD', 'RHCOS']
         - not (guest_os_ansible_distribution == "Ubuntu" and
                guest_os_ansible_distribution_major_ver | int >= 22)
         - not (guest_os_ansible_distribution == "Debian" and
@@ -53,12 +53,11 @@
 
     - name: "Rescan scsi devices in {{ guest_os_ansible_distribution }} {{ guest_os_ansible_distribution_ver }}"
       when: >
-        (guest_os_ansible_distribution == 'Flatcar' or
+        (guest_os_ansible_distribution in ['Flatcar', 'Fedora', 'RHCOS'] or
          (guest_os_ansible_distribution == "Ubuntu" and
           guest_os_ansible_distribution_major_ver | int >= 22) or
          (guest_os_ansible_distribution == "Debian" and
-          guest_os_ansible_distribution_major_ver | int >= 12) or
-         guest_os_ansible_distribution == "Fedora")
+          guest_os_ansible_distribution_major_ver | int >= 12))
       block:
         - name: "Rescan all hard disks"
           ansible.builtin.shell: |