"IP already exists in the network" after upgrading to VCSA 6.7

Products

• VMware vCenter Server

Issue/Introduction

Symptoms:

• Upgrading vCenter Server Appliance to 6.7 fails.
• In the var/log/vmware/upgrade/upgrade-export.log file, you see entries similar to:

2018-06-04T05:06:36.991Z  Stderr: 04/06/2018 05:06:36 [ERROR] Cannot run /sbin/ifup eth0 command. Unknown error. Return code : 256 output: Make sure the interface is down or not assigned any IP
eth0 is DOWN or not assigned an IP. Bringnig eth0 up...
Can not find the manual filename, let us search for the auto filename
Performing duplicate address check for IPv4 address xx.xx.xx.xx
Error: IP already exists in the network

Unable to set the network parameters

2018-06-04T05:06:36.991Z  ERROR: setnet failed : {
    "detail": [
        {
            "id": "install.setnet.set.network.vami",
            "translatable": "Error setting network. Details : %(0)s",
            "localized": "Error setting network. Details : 04/06/2018 05:06:36 [ERROR] Cannot run /sbin/ifup eth0 command. Unknown error. Return code : 256 output: Make sure the interface is down or not assigned any IP\neth0 is DOWN or n
ot assigned an IP. Bringnig eth0 up...\nCan not find the manual filename, let us search for the auto filename\nPerforming duplicate address check for IPv4 address xx.xx.xx.xx\n\u001b[1;31mError: IP already exists in the network\u001b[0;39
m\n\nUnable to set the network parameters\n",
            "args": [
                "04/06/2018 05:06:36 [ERROR] Cannot run /sbin/ifup eth0 command. Unknown error. Return code : 256 output: Make sure the interface is down or not assigned any IP\neth0 is DOWN or not assigned an IP. Bringnig eth0 up...\nCa
n not find the manual filename, let us search for the auto filename\nPerforming duplicate address check for IPv4 address xx.xx.xx.xx\n\u001b[1;31mError: IP already exists in the network\u001b[0;39m\n\nUnable to set the network parameters\
n"
            ]
        },
        {
            "id": "install.setnet.set.network",
            "translatable": "Failed to set network",
            "localized": "Failed to set network"
        }
    ],
    "resolution": null,
    "componentKey": "setnet",
    "problemId": null
}
. Stderr:
2018-06-04T05:06:37.16Z ERROR apply_networking Command /bin/python /bin/setnet --locale en --statusFile /var/log/vmware/upgrade/setnet_status.json completed with non-zero exit code 1.
2018-06-04T05:06:37.17Z INFO transfer_network Capturing network state after applying source networking.

Note: The preceding log excerpts are only examples. Date, time, and environmental variables may vary depending on your environment.

Environment

VMware vCenter Server Appliance 6.7.x

Cause

This issue occurs when the source VCSA is still shutting down (holding the IP address) and at the same time the target is setting the network.

Resolution

This issue is resolved in vCenter Server Appliance 6.7 Update 1, available at VMware Downloads.

Workaround:
To workaround this issue if you do not want to upgrade:

Note: It is mandatory to take a snapshot before performing the steps mentioned above below.

1. If there are any other issues faced during the upgrade, revert to the snapshot taken, instead of powering on the source VCSA directly.
2. Take an SSH session to the vCenter Appliance and run these commands:

mv /usr/sbin/shutdown /usr/sbin/shutdown-backup

echo -e '#!/bin/bash\nsystemctl start systemd-networkd\nip link set eth0 down\nip link set eth1 down\n/usr/sbin/shutdown-backup -h now' > /usr/sbin/shutdown
chmod +x /usr/sbin/shutdown

3. Once these changes are applied proceed with the upgrade.