I would like to ask a question, vCenter cluster hosts are randomly disconnected and automatically connected.What's the reason?Thank you very much

[xht0201]

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[daphnissov]

Without you providing much more information, we cannot help you.

[xht0201]

There are three hosts in the vCenter cluster, which are disconnected randomly every few minutes, showing no response, and connected automatically after a few seconds.This happens frequently.May I ask what the reason is? I will upload the log of vCenter, thank you very much!daphnissov​

I have done the following operations:

1, the network did not lose packets

2, shut down vCenter firewall and vCenter reboot

3,Create a new cluster and re-add the ESXI

4,ESXI has restarted hostd and Vpxad,The ESXI host can be managed separately by the vSphere client,

Also try to open UDP902 port and TCP443 port at vCenter firewall,

The problem is not resolved.

How to upload logs?

[Vijay2027]

If it's windows based vC refer to below communities thread:

KB4338815 KB4284815 KB4339093 KB4338824 vCenter Server 6.0 U2 Host Network Connection Failure

Vcentrr server 5.5u3c failing after July ms Patches

[Vijay2027]

In addition to my previous post refer: https://blogs.msdn.microsoft.com/psssql/2018/07/26/july-10-2018-windows-updates-cause-sql-startup-issues-due-to-tcp-port-is-already-in-use-errors/

[daphnissov]

What's the moral of the story? STOP USING WINDOWS VCENTER :smileylaugh:

[RonnyNorway]

It might be that something is blocking ICMP ping, because it looks like heartbeats time out. So check if there might be an obstrucion in the path from hosts to vcenter. If you are using Windows vcenter check that Windows firewall allows pings from the hosts.

[xht0201]

• The firewall is off

[RonnyNorway]

Somehow heartbeats og missing then.

What kind of Storage do you use?

Have you got 2 datastores for HA heartbeats?

Are you using NAS (NFS) datastores? (NFS can cause timeouts)

Do you have any other firewall between the hosts and the vcenter?

[vijayrana968]

Want to inform you that this issue has been noticed on Windows based vCenters after July , 2018 patching with 2018-07 Security Only Quality Update for Windows Server 2012 R2 for x64-based Systems (KB4338824)

You have to uninstall July, 2018 monthly roll-up and check.

[stanislav_musil]

few questions:

- is MTU set on vCenter, ESXi hosts, switches same?

- ping is working from ESXi hosts to vCenter without interruption?