Accessing the VAMI returns error "This appliance cannot be used or repaired because of failure was encountered. You need to deploy a new appliance"

Products

• VMware vCenter Server

Issue/Introduction

Symptoms:
When trying to access VAMI, the URL is changed to https://FQDN/IP:5480/configure/#/installer? and page throws the error "This appliance cannot be used or repaired because of failure was encountered. You need to deploy a new appliance"
vCenter WebClient is working fine and vCenter is manageable.

In vCenter logs, we can see the below entries:
/var/log/vmware/applmgmt/applmgmt.log
YYYY-MM-DDTHH:MM:SS [42850]DEBUG:vmware.vherd.transport.vapi:Only ['INSTALL_IN_PROGRESS'] block []
YYYY-MM-DDTHH:MM:SS [42850]ERROR:vmware.appliance.update.update_functions:Can't read JSON file /etc/applmgmt/appliance/software_update_state.conf [Errno 2] No such file or directory: '/etc/applmgmt/appliance/software_update_state.conf'
YYYY-MM-DDTHH:MM:SS [42850]DEBUG:vmware.appliance.update.update_state:No update state file. Will create a new one
YYYY-MM-DDTHH:MM:SS [42850]ERROR:vmware.appliance.update.update_functions:Can't read JSON file /etc/applmgmt/appliance/software_update_state.conf [Errno 2] No such file or directory: '/etc/applmgmt/appliance/software_update_state.conf'

The file /etc/applmgmt/appliance/software_update_state.conf didn't exist.

Environment

VMware vCenter Server Appliance 6.7.x

Cause

This is similar to the issue mentioned in KB : Accessing the VAMI returns error "Update installation in progress" after recovering from a failed vCenter update or vCenter version upgrade

VCSA is under the impression that the installation process is ongoing, however it is unable to find the files which are created during this process.
YYYY-MM-DDTHH:MM:SS [42850]DEBUG:vmware.vherd.transport.vapi:Only ['INSTALL_IN_PROGRESS'] block []

Resolution

The files prechecks-succeeded, export-succeeded & import-succeeded may not be present in /var/log/vmware/upgrade. We will need to create these files manually by using touch

# touch prechecks-succeeded
# touch export-succeeded
# touch import-succeeded
# ls -l   | grep succeeded

-rw-r--r-- 1 root root    0  prechecks-succeeded
-rw-r--r-- 1 root root    0  import-succeeded
-rw-r--r-- 1 root root    0  export-succeeded

Post this, we can refresh the VAMI page and it should be working as expected.