vCenter Server restore fails when DNS configuration includes both IPv4 and IPv6 addresses

Products

• VMware vCenter Server

Issue/Introduction

A vCenter Server restore operation may fail when the DNS or network configuration includes both IPv4 and IPv6 IP addresses.

During the restore process, the task stops unexpectedly due to a parsing error related to the static IPv6 prefix configuration. This issue prevents the restore workflow from completing successfully.

The failure can be observed in the vCenter Server restore logs located at: /var/log/vmware/applmgmt/restore.log

File "/usr/lib/applmgmt/base/py/vmware/vherd/base/pint.py", line 847, in <listcomp>
    return [argumentParse(varType.varType, el) for el in inputVar]

File "/usr/lib/applmgmt/base/py/vmware/vherd/base/pint.py", line 804, in argumentParse
    d[name] = argumentParse(value, inputVar[name])

File "/usr/lib/applmgmt/base/py/vmware/vherd/base/pint.py", line 819, in argumentParse
    raise Error(ARG_PARSE_FAIL, "input not a long: %s" % inputVar

Environment

VMware Cloud Foundation 9.0

Cause

This issue occurs due to an incorrect data type used for the IPv6 prefix in the backup-metadata.json file.
When static IPv6 is configured, the prefix value is stored as a string (for example, "128") instead of an integer (128). During the restore process, vCenter Server fails to parse this value correctly, resulting in an argument parsing failure and causing the restore task to fail.

Resolution

To work around this issue, update the IPv6 prefix format in the backup-metadata.json file and then retry the restore operation.

Steps to resolve : 

Navigate to the backup location on the remote backup server.

• Make a backup copy of the metadata file:
• Edit the original backup-metadata.json file.
• Locate the IPv6 configuration section and modify the prefix parameter by changing it from a string to an integer.

Incorrect format:

"prefix": "128"

Correct format:

"prefix": 128

Example of the corrected IPv6 configuration:

"ipv6": {
    "dhcp": false,
    "addresses": [
        {
            "address": "<ipv6 address>",
            "prefix": 128
        }
    ],
    "autoconf": false,
    "defaultGateway": "<gateway>"

}

Save the file and retry the vCenter restore task.