Avamar: Upgrade workflow fails with "Linux root password validation failed"

The Avamar upgrade workflow fails wit the following error:

Linux root password validation failed

The Avamar installer log (/usr/local/avamar/var/avi/server_log/avinstaller.log.0) also reports a password error:

...
INFO: [aviguiserv:10.11.12.13] making rest call: http://10.11.12.13:7580/avi/service/userinput/validate/2c0e0c74e06aff1f1027950fbf90fe85/linux_root_password/************/password_field
Nov 26, 2021 1:36:55 PM com.avamar.avinstaller.process.UserInputManager buildCommands
INFO: /data01/avamar/repo/temp/AvamarUpgrade-7.4.1-58.avp_1511688016595/scripts/validate/default, --input_name=linux_root_password, --value=**********, --input_type=password_field
Nov 26, 2021 1:37:25 PM com.avamar.avinstaller.process.UserInputManager validateUserInput
INFO: validation error message: Validating Password Failed.

The fully qualified domain name (FQDN) does not display correctly when using the hostname command:

hostname -f

avamar1

The entry in the /etc/hosts file for the Avamar grid is incorrect. The FQDN and hostname have been swapped:

grep <hostname> /etc/hosts

-- Or --

grep "<Avamar-grid-IP-address> /etc/hosts

Examples:

grep avamar1 /etc/hosts

grep 10.11.12.13 /etc/hosts

Example output:

10.11.12.13 avamar1 avamar1.company.com

1. Log in to the Avamar Utility Node as admin.

2. Elevate to root privilege.

3. Make a backup copy of the hosts file:

cp -p /etc/hosts /etc/hosts.`date +%y%m%d`

4. Edit the /etc/hosts file:

vi /etc/hosts 

5. Update the invalid entry:

From:

10.11.12.13 avamar1 avamar1.company.com

To:

10.11.12.13 avamar1.company.com avamar1

(The actual values here would be changed relevant to the environment)

6. Save the file and exit.

7. Verify the contents of /etc/hosts is correct:

10.11.12.13 avamar1.company.com avamar1

The upgrade workflow should now run without issue.