"The source machine hostname '192.168.0.1' resolves to IPv6 address(es) '::ffff:192.168.0.1', but IPv6 networking will not be preserved after the upgrade" while upgrading VCSA 6.5/6.7 fails at precheck
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Article ID: 309025
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Updated On:
Products
VMware vCenter Server
Issue/Introduction
Symptoms:
vCenter Appliance 6.5 to 6.7 Upgrade is stuck at Stage 2 at Pre-Checks
vCenter is deployed using IP as PNID
IPv6 is disabled on vCenter
Error stack seen in PreChecks stage on Phase 2 where IP of vCenter is 192.168.0.1:
"Error: The source machine hostname '192.168.0.1' resolves to IPv6 address(es) '::ffff:192.168.0.1', but IPv6 networking will not be preserved after the upgrade. This will prevent certain services preferring IPv6 from establishing network communication. Resolution Either remove the DNS IPv6 entry for hostname '192.168.0.1' or change the network configuration of the source machine to pure IPv6 or in case dual networking stack is needed, set a static IPv6 address."
Command below return values with both ipv4 and ipv6 format (::ffff:IP)
[email protected] +short VC_IP A VC_IP AAAA for example below command returns DNS information from localhost: dig @127.0.0.1 +short 192.168.0.1 A 192.168.0.1 AAAA for example below command returns DNS information where DNS is 192.168.0.100: dig @192.168.0.100 +short 192.168.0.1 A 192.168.0.1 AAAA 192.168.0.1 ::ffff:192.168.0.1
Environment
VMware vCenter Server Appliance 6.7.x VMware vCenter Server Appliance 6.5.x
Cause
Upgrade scripts checks for IPv6 resolution and if seen it will check for configuration of IPv6 on vCenter side. If it's not enabled, it will fail with above error.
Resolution
As stated, resolution is from the error stack:
Either remove the DNS IPv6 entry for hostname '192.168.0.1' or change the network configuration of the source machine to pure IPv6 or in case dual networking stack is needed, set a static IPv6 address.
As per above the options are:
Configure DNS without IPv6 information or
Configure the vCenter to have also IPv6 information
Workaround: Steps to workaround the pre-check:
Add required static IP addresses into /etc/hosts file (all VC and PSC's needed)
Comment (hash) DNS servers in /etc/resolv.conf
Restart dnsmasq service by using systemctl restart dnsmasq.service
Retry the prechecks page which should now allow you to go to next page
Add/enable DNS servers back in /etc/resolv.conf by removing the hash sign