Running vCenter in a virtual machine within a distributed switch is not supported

Update: This post has been updated on Feb 23, 2011 as I have been kicked right and left by my colleagues at VMware, as this post used to be titled  “Running vCenter in a virtual machine within a distributed switch is not supported”, where its actually supported. Unfortunately, this info was communicated to me by VMware support when I was working at a partner before joining VMware but that was at the early dates when vDistributed Switch was first released. So here I am correcting my statement & mentioning its actually supported, but I still don’t recommend connecting your vCenter VM to the distributed switch it manage. The way I normally recommend doing things is actually to utilize a standard vSwitch for Management/VMkernel port groups where vCenter (running as a VM) connect to the Management port group. This configuration usually help avoid pitfalls. The below post has been updated accordingly.

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Many companies have always considered running Virtual Center in a virtual machine due to many advantages found below:

· Server Consolidation: instead of dedicating an entire physical server to VirtualCenter, you can run it in a virtual machine along with others on the same ESX Server host.
· Mobility: by encapsulating the VirtualCenter server in a virtual machine, you can transfer it from one host to another, enabling maintenance and other activities.
· Snapshots: A snapshot of the VirtualCenter virtual machine can be used for backup,
archiving, and other similar purposes.
· Availability: using VMware HA, you can provide high availability for the VirtualCenter server

All the advantages above has got me to run most of my customers virtual centers as virtual machines. Though it got my attention that running vCenter into a virtual machine on vSphere with connecting it to vDistributed switch that it manage is not recommended. That makes sense as vCenter governs the distributed switch. Imagine the case where your vCenter fail while it was connected to the vdistributed switch that it governs. If you try to bring up the vCenter with HA, you could run in some pitfalls. You need vCenter connected and running for the vSwitch configuration changes & vCenter needs the vdistribute switch to work.

Its worth mentioning that it’s actually recommended to still keep the Management & VMkernel ports on a standard vSwitch where you can still connect your vCenter, & utilize the vDistributed switch for all the VMs Port Groups & traffic. This will help you avoid a lot of pitfalls.

I thought I will mention this on here to ensure that you avoid this ugly mistake. If you have read this post & it saved your job, please award me a comment.

Comments

  1. Thank you for your information. I was running VCenter Server 2.5 in a VMware (virtual server 2003 std) and I got in to a mesh. Thanks god that this is just a lab enviornment. I had to remove all my sql and all vcenter component and vshpere and will try to re-install and see if it works. Show how all my VMs where disconneted from VCenter server 2.5. Stating my managed server IP is different than host. I will be running Vcenter 2.5 on a physical server now.

  2. HI Sajjad,

    I hope my article helped you, but I am not sure exactly what is your scenario. Are you actually using a vdistributed switch? As you did not mention that at all. If not then this post is not related to your case, & you can always run vCenter in a virtual machine on ESX 4 if you are not using distributed switches. Or you can even use distributed switches, but still keep some traditional vswitch for the vCenter to use.

    I hope this help,
    Eiad

  3. Hi guys. Just a couple of clarifications in case anyone else reads this blog and gets the wrong idea.

    1. vCenter running as a VM while connected to a vNetwork Distributed Switch definitely *IS* supported. You will have no problems getting support from VMware if you run vCenter in such a configuration.

    2. vCenter isn’t required to be running for the vDS to work. It is required for the setup or reconfiguration of the vDS but, once configured, the vDS will continue to operate regardless of whether or not vCenter is running.

    Regards
    Andrew Mitchell
    Consulting Architect
    VMware Professional Services.

  4. Hi Andrew,

    Hi Andrew,

    Thanks for the info, & I am sorry if my post give a misconception about the above two points as its not meant to be :).

    I mean I clearly mentioned its not supported to run vCenter as a VM if it get connected to the Distributed switch. Did this change lately?

    I will leave your comment in here for people to see it, if you want me to add something to the article to avoid people getting confused let me know.

    Sorry for the delay in posting the comment, though I was out of town for a while & actually still not back yet.

    Enjoy,
    Eiad

  5. I never virtualise VC the pitfalls just dont justify the benefits IMO.
    After a complete failure (san or power) you want a nice stable server on which to look out from and get the various elements back up and running again without having to hunt around your hosts looking for your VC and in some cases trying to find the virtual SQL server first and get that running. Just today we had one where the .vswp was locked and the VC vm wouldn’t power on again.
    Physical VC if you want an easy pain free life.

  6. Hi Eliot,

    Unless if you are using heart beat then you can be running at the normally higher risk of your VC server crashing then you can end up without VC for some time.
    I have actually seen many customers who got VC virtualized without a problem. Further, they regularly have an image backup to somewhere else, so they can restore it in no time if a storage failure happen.
    Further, for most customers a storage failure can equal a disaster where they can operate most of the virtual infrastructure from DR till head office come back.

    I guess different people got different view on doing things. Its more of the customer requirements & which approach best meet that particular requirement. I don’t see it bad to implement VC as a VM or as a physical it all depend on the customer requirements

    Regards,
    Eiad

  7. Andrew Mitchell says:

    Hi Eiad and sorry for not responding earlier.

    “I clearly mentioned its not supported to run vCenter as a VM if it get connected to the Distributed switch.”

    That is not correct. Such a configuration has always been supported.

    “Did this change lately?”

    No. It’s always been supported.

    Our *recommendation* is not to connect it to the vDS if you can avoid it as you could get into a situation where it’s very difficult to access the vCenter server to fix the problem if you misconfigure the vDS. Having said that, it doesn’t mean it’s not supported – It definitely is, and there are some situations where you hve no choice. eg. You want to run vCenter as a VM and you only have 2 X 10GE NICs on the server. In that situation you would assign both NICs to the vDS for redundancy and connect the vCenter VM to the vDS. That is fully supported.

  8. Andrew Mitchell says:

    @Eliot
    “get the various elements back up and running again without having to hunt around your hosts looking for your VC and in some cases trying to find the virtual SQL server first and get that running.”

    If you design your environment in accordance with our best practices for virtualising vCenter you should never get into such a situation. If vCenter is virtualised you should disable DRS for that VM (vSphere 4.0 and earlier) or use DRS host affinity (vSphere 4.1) to ensure the VM stays on a known host. If the database is also virtualised you should apply the same settings to it as well.

  9. Hi Andrew,

    Thanks for the update, but do we have any document which state its supported as it seems I am not the only one who called support and got the answer its not supported.

    Check out the following on our forums: http://communities.vmware.com/message/1414822#1414822

    I really appreciate your follow up on this & will really appreciate it if you can point me to any document that state its supported.

    Regards,
    Eiad

  10. I have totally screwed the pooch on this one. Running ESXi 4.1 and vCenter 4.1 (SQL and vCenter are VM’s).

    I created a bitchen vDS and it was working perfectly. Decided to eliminate my vSS and put all networking on each ESXi host on vDS. Worked fine for a while before the wheels started to fall off. In attempting to return the vKernel ports to vSS’s, it has just made matters worse. Now my vCenter is totally out of sync with the ESXi hosts and the infrastructure is struggling to make any changes.

    If I cannot get things stablized soon, I will probably rebuild from scratch. Luckily I am still in preproduction on this farm and have the luxury of a rebuild. I will leave vKernel ports on vSS’s, along with vCenter, and just put VM networks on vDS’s.

    Mr E

  11. Hi Mr E,

    I think it is a good idea to still keep the vKernel ports on vSS :).

    Enjoy,
    Eiad

  12. Kamil Azmer says:

    Hi.

    I have question on the design vCenter on virtual machine with vDS.

    1. If we have limited of physical NIC, e.g : 2 NIC, should we did pure vDS, but what is the impact of putting in vDS. Correct me if i’m wrong, If vCenter down, vDS still operate but unable to manage, BUT, vCenter unable to be power-on due to vDS unable to manage. and on this case, it’s required to create temporary vSS and change the network to temporary vSS. But! It’s vCenter able to take-control back the vDS by using temporary vSS without physical NIC or it’s required the physical NIC also?

    2. What is vmware best practice on this solution, it’s the best recommended to put vCenter on virtual machine? Since i go thru the vSphere Design Workshop, it’s say to putting the vCenter on virtual but not mention on vDS. Should i applied hybrid vDS on the environment when vCenter on virtual?

    3. In term of support by VMware, it’s this will be supported on VMware, or it’s will not supported? May someone clearly on this.

    Thanks,
    Kamil Azmer

  13. Hi Kamil,

    Having vCenter on vDS in your configuration is supported. Things have quite changed since the first release of vDS and there is not much of a problem now to attach vCenter to vDS.

    In your scenario if you require the features of vDS & you have already paid for Enterprise Plus then I will definitely go with pure vDS.

    Further, in the Design Course if you go through the book again it has the best practice to have vCenter as a VM and it mention that its as well to have it connected to the vDS in your case. I don’t remember the page, but I am positive I read that in there. Having vCenter down will only stop you from managing the vDC, but will not affect the operations. Further, you should be fine to bring vCenter back on, as I mentioned things has been dramatically improved since vDS was releases & since this post was written.

    I hope this help.

    Regards,
    Eiad

  14. Kamil Azmer says:

    Hi Eiad.

    That mean, even the vCenter(VM) down and other VM need to power up that attached to vDS, we still able power-on the VM?

    How about if there are putting vShield, and both VM(vCenter and vShield) down. It’s affecting any operation?

    Correct me, When vCenter was down, the current VM power-on is still running, but unable to managed it. And to power-on the other VM that already(down) attached to vDS will be failed? It’s correct?

    Thanks.

  15. smartboy says:

    Hi guy!
    When I join my vcenter server to a distributed switch, all the connections on the distributed Switch will go down. Please help me.

  16. Hi Smartboy,

    I really have not seen that before. Can you please collaborate more about your environment & if you have found the cause yet?

    Thanks,
    Eiad

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