vCenter unavailable in Enhanced Linked Mode due to network connectivity failures

Products

• VMware vCenter Server

Issue/Introduction

• A vCenter server does not appear in Enhanced Linked Mode inventory.
• In the vSphere Client for both the missing vCenter as well as any vCenters that are still connected there are error banners with messages such as: "Could not connect to one or more vCenter Server systems:https://vcenter_fqdn:443/sdk"
• The disconnected vCenter is unable to reach its partners over the network using tools such as ping, netcat to port 443, and/or perform forward or reverse lookup to them.

Environment

vCenter Server with Enhanced Linked Mode enabled

Cause

Network connectivity issue between the vCenters in Enhanced Linked Mode.

Resolution

Work with network and/or security operations teams to restore bidirectional IP connectivity along these paths:

• VCSA to VCSA: Ports 443 (HTTPS) and 2012 (vmdir RPC)
• VCSA to Active Directory Domain Controllers: Port 389 (LDAP) or 636 (LDAPS).

Make sure that both forward and reverse DNS lookup are working for all of the vCenter nodes as well. Once the network connectivity is restored, verify the replication status using:

/usr/lib/vmware-vmdir/bin/vdcrepadmin -f showpartnerstatus -h localhost -u administrator