Weird issue with Sever 2102R2 2 node cluster. Has worked for several years but during patch Tuesday reboots 2nd node could not rejoin cluster. Cluster validation tool indicated it was a network error and Failover cluster manager shows same issue even though all NICs are up and can be reached via Ping, etc. Network configuration has 4 network adapters. #1 is on 192.168.140.10(LAN) on VM01 and 192.168.140.40(LAN) on VM02. #2 on both is setup as VM_Main in Hyper-V so doesn't have an IP address just Hyper-V virtual switch. #3 is on iSCSI network 192.168145.7(SAN) on VM01 and 192.168.145.11(SAN) on VM02. #4 is on iSCSI network 192.168.145.8(SAN) on VM01 and 192.168.145.12(SAN) on VM02. The SAN is connected to 2 - HP2530 switches with one adapter from each host and each controller (2) on the equalogic on each switch. The Hyper-v vEthernet adapter is on 192.168.140.23 and shows enabled on VM01. On VM02 the adapter is set to automatically detect and disabled. I don't remember what the normal status of the vEthernet adapter was on VM02 as I set it up a while ago and it has worked (I was thinking the owner of the vEthernet switch was the controlling node in the cluster so disabled was normal for the non-controlling node). All adapters have IPv6 set to auto except the iSCSI SAN NICs where IPv6 is not installed. Cluster network 1 192.168.140.0 is set up for cluster communication.
On the cluster the cluster service on VM02 won't start and the network details in the cluster manager show that Cluster Network 1 - 192.168.140.40 (LAN) and Cluster Network 2 - 192.168.145.11 (SAN) are unreachable. Both networks are running fine on VM01 and all virtual machines are running on VM01. Again I can ping all interfaces and the binding order is the same on both nodes - LAN, VM_Switch, vEthernet Switch, SAN1, SAN2.
I have read quite a lot over the last few days and the indication is that the networks are not set up correctly but I am not sure how to change it. Again it has worked for quite a while and other than patches not sure what changed.
I noticed that when I ping VM01 by host name it responds with the IP address of the vEthernet (192.168.140.23) adapter not the IP address of the host (192.168.140.10). Also, for reference, the switches are set up with two ports on each switch in LACP mode; one switch is set to active and the other to passive.
Sorry for such a long post but I know the more you know the easier it is to diagnose.