No network connection for VM after manually migrating to new host

[kevcor]

We've added six new hosts to our environment, and I've been tasked with testing the VLAN connections on each of them before we migrate production VM's to them.  This is probably a simple problem but I'm new to VMWare and need some help.  I've already talked to our network guy, and he assures me the physical switches are setup and working correctly.  We're working a vDS.

I'm testing 14 VLANs on six new hosts.  All but one work consistently.  (All of them work on the original hosts that were in place before.)  I have a static IP setup on my test VM and MAC is set to automatic.  I've verified the MAC does not change when migrating to other hosts and the correct VLAN is listed in the network settings for the VM (it's not blank).  The VLAN will work on three of the six hosts but not all at once.  The weird thing is the working hosts constantly change.  For example, this morning hosts11, 12, and 14 might work but this afternoon that could change to hosts12, 14, and 16.  I don't understand why they would change on their own.

My test consists of powering down the test VM, manually migrating it, powering it back on, then pinging it from my computer.  Obviously everything is working when I get ping replies.  When I don't get replies, the test VM has a yellow exclamation point over the network icon in the system tray.

What do I need to do to resolve this?

[BenLiebowitz]

Have you confirmed that the vlan is tagged properly on all the required ports on the switch side? 

Is the vlan ID set properly on the required portgroup on each of the new hosts? 

These are the things I would start with to troubleshoot this issue...

[kevcor]

I'll have to ask the net admin to confirm tagging on the switches.

I verified the VLAN on the protgroup in Inventory > Networking.  I don't understand  what you mean by "on each of the new hosts."  I don't see how to do this on the hosts.

Thanks for your help.

[BenLiebowitz · Accepted solution]

How is the network configured?  Do you have a different NIC port/cable for each vlan or are they using Trunking on the switch side? 

If you're using trunking on the switch side, then your virtual switch portgroup needs a VLAN ID to match the vlan thats being trunked.  It doesn't matter if it's a standard switch or distributed switch... you still need that vlan ID. 

I've seen the random issue you're having if the VLAN is missing on one or more of the uplinks on the switch side.      

[kevcor]

I spoke to my net admin yesterday and asked him to double check the config on the switch.  I'll report back when I hear something from him.

[BenLiebowitz]

Sounds like a plan. 

[kevcor]

We've got it working.  Turns out there were two problems.  The first was an error with MLAG config on the physical switch; the second was an error with ports on the VDS.  Thanks!