vCenter Network Partitioned

Have you ever experienced a Network Partitioned warning in vSphere 5? Hopefully not, but if you find yourself with this warning in vSphere. Don’t panic its not as bad as it could have been in 4.x.

This literally just means that the host can not communicate with any of the designated VMK’s checked off for management traffic. In my case it happened after making network changes to my infrastructure. In this case I still had bonded links at my switches, but somehow the VMK load balancing algo had switched to “route based on originating port ID”, this load balance algo doesn’t work with bonded NICs, and needs to be “route based on IP hash”. My end goal was to get off bonded links for my host and use the default load balance algo that VMware uses, as this can be down with non stacked switches and can be done with minimal switching knowledge (in case others need to manage the system in the future).

It took me a little bit to catch the issue, cause the symptoms were that each host could ping any device in their respected management subnets but NOT the other host, flat /24 subnet too, really had me baffled. As I couldn’t vMotion in this state either, but lucky the VMs on each host remained active (as they have separate communication VMPGs on dedicated physical connections).

Once I caught the error, I was able to verify vMotion worked again. That’s all there is to it!

To Paraphrase to solution:

1) Check which VMKs have management checked off.
2) Check those vSwitches physical connections.
3) If multiple ports check configs on physical switch and load balance algo.
4) Google any errors along the way.
5) Check host to host communication by consoling into host and using vmkping.

Jan 2018 Update

I remember this…

Leave a Reply

Your email address will not be published.