During a rebuild of my home lab recently I stumbled on to problem which means I need to update the VMware Workstation \ Fusion ESXi build instructions I have previously issued. Due to me having to rebuild the hosts one at a time to ensure that the USB drives use the mbr partition instead of GPT I followed my previous instructions of using a VM in VMware Workstation to rebuild all three USB drives, all was good with the first host running but as soon as I added hosts 2 and 3 I started experiencing issues with the hosts not working well with each other. Each host was able to ping components outside of themselves but were unable to ping the other hosts, making things even stranger still was that I couldn’t add the hosts to vCenter either, having done the obvious and made sure I hadn’t made any mistakes with networking (all using the correct IP addressing, subnet masks and DNS servers etc) I put a post out to Twitter asking for some advice, this wasn’t a new build having had been used previously to build out the Shuttle servers so I knew that the ISO image was fine so then someone asked what happened with a single server being on line, powering down two of the hosts I found myself able to ping the remaining host without issue, however as soon as I powered up another host I encountered dropped pings all over the place.
Thinking perhaps that I had a faulty NIC card (it happens and is the reason I have a spare one sitting around) I started playing with all three hosts to see which one of the three could be causing the issue, as it turns out none of them and all of them. Individually each host performs as expected, it’s 100% pingable, able to join vCenter and works as expected but adding any other host to the environment would cause the entire environment to break down and become un-responsive.
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