vCenter standard vSwitch portgroups + different VLAN settings

[donJ201110141]

Hi,

In vCenter Standard vSwitches, vCenter allows, identical name-standard portgroups on different ESX hosts to be  on different vlans. Is this  considered as a misconfiguration? Or is it frowned upon? (Or better yet, can there  be any real use cases?) Because ultimately the traffic wouldn't go  through with this different vlan configuration even though the  portgroups have the same name to them.

For example:

ESX1--vswitch1--MYportgroup(vlan5)

ESX2--vswitch2--MYportgroup(vlan10)

In distributed vSwitches we don't have this porblem, since there will be a single portgroup for all the esx servers.

Thanks in advance for anyone who can shed some light in to this issue!

[a_p_]

IMHO there is no real world use case for having a mixed setup. I think the reason you can do this is just because the vSwitches on different hosts have to be configured manually (except you use host profiles).

André

[donJ201110141]

Thanks André, that's exactly what I thought too. Anyone else willing to share opinions?  Appreciate the inputs!

Thanks!

[bilalhashmi]

Just like Andre mentioned as well. I can see any real use case for this. If anything I see a disaster waiting to happen. Lets say you have two hosts with Portgroup name set to portgroup 1. One host 1, Portgroup1=VLAN2 and on host 2, Portgroup1=VLAN3.

If you have DRS enabled on this host and a VM which was happliy living on host 1 because it can only communicate through VLAN2 may stop communicating withe the network if DRS decides to move it to host 2. I just dont know why anyone would want to do that.

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[jasonawinters · Accepted solution]

Definitely a case FOR using vDS in a production system, where this problem would not be an issue. Thinking about it, though, it could be a useful thing in a test environment, where you may need to test configurations or connect to different parts of the network on a "utility" VM.. if the VM's NIC was set to use DHCP, its IP configuration could be automatically changed when it moved over to different VLANs, etc.. It might be useful where you had a network configuration where you were forced to connect specific VLANs to specific hosts. Then by simply vMotioning the VM to another host, you could dynamically change it's location on the network.

I would most definitely say it is not a best practice for a production environment, though...

[Texiwill]

Hello,

A case for vDS or for Host Profiles, either works. In addition, I suggest use of a compliance checker to ensure everything is correctly setup. This is a case where you would need a tool to analyze your systems and point out the differences (ala Host Profiles), then take corrective action.

Best regards,

Edward L. Haletky

Communities Moderator, VMware vExpert,

Author: VMware vSphere and Virtual Infrastructure Security,VMware ESX and ESXi in the Enterprise 2nd Edition

Podcast: The Virtualization Security Podcast Resources: The Virtualization Bookshelf