Creating an IP-Pool for VC Ops

I was importing the VC Ops virtual appliance and during the import I got a question around IP addresses. So I figured I would enter two IP addresses and that would be it. As soon as I powered on the VM I received the following error:

Cannot initialize property ‘vami.netmask0.VM_1′ since network ‘VM Network’ has no associated IP Pools configuration.

I figured this would be simple so I jumped back to “home” and went to the network section… Nothing around IP Pools. Even on a host or cluster layer there was nothing. Luckily my colleague Cormac jumped in and said check the “Datacenter” object, there should be an IP Pool tab there. He was right. Weird place and definitely something that needs to be improved. Anyway, configuring an IP Pool itself, now that I found it, was easy:

  1. Click your Datacenter object
  2. Go to the “IP Pools” tab
  3. Click “Add”
  4. Fill out the details:
    1. Subnet: which network will be used and what is the mask? (You can use a subnet calculator if you don’t know…)
    2. Enter the details of the gateway
    3. Specify a range, the format is “″, this would result in a range from until (10 addresses counting from .10)
    4. Don’t forget to tick the “Enable IP Pool” check box
    5. Click on the “Associations” Tab and associate it to a network!
    6. Also, fill out the DNS and proxy details if and when required.
  5. This is what it should look like:

It is as simple as that, but indeed not easy to find hence the reason I figured a short article was in place.

PS: Creating a range and enabling the “IP Pool” is not required. “Enable IP Pool” enables the use of the Range. In this example I had to use a range as I could only use a specific range of this subnet.


Re: when to disable HA? /cc @hashmibilal

Bilal Hashmi wrote a nice article about HA today and in this article he asked a couple of questions. As I think the info is useful for everyone I decided to respond through a blog article instead of by commenting.

Let me start by saying that in general HA should never be disabled. The later versions of vSphere have a neat option called “Enable Host Monitoring”. This option should be used for scheduled network maintenance. The difference between disabling host monitoring and disabling HA is that disabling host monitoring does not cause a full reconfiguration (see screenshot below) of HA and a new election process. Just the “host monitoring” functionality is disabled, which is what you want in this scenario.

Bilal asked multiple questions / made multiple statements in his article, I will respond to two of these specifically to explain the way HA handles failures/isolation:

In this case within 30 sec of the management network outage, each host would have declared itself isolated and wont attempt to restart any VMs like the primaries would in vSphere 5.

So why is this? As soon as a Master is isolated it will drop “ownership” of datastores on which VMs are running that are part of its cluster. Before the other hosts trigger the isolation response for a given VM they will validate if the datastore on which this VM is stored is “owned” by a master. In the case of a cluster wide isolation due to a network outage / maintenance the ownership would be dropped and this would result in HA not triggering the isolation response. This is a major change compared to vSphere 4.x and prior!

Now what happens when the network outage is over and the hosts are in a position to talk to each other? I have not been able to find documentation on whether an isolated host will enter an election (vSphere 4 or 5) ones the communication channel is open and bring the cluster back to life.

Lets focus on vSphere 5.0 as that seems most relevant. A host remains isolated until it observes HA network traffic, like for instance election messages OR it starts getting a response from an isolation address. Meaning that as long as the host is in “isolated state” it will continue to validate its isolation by pinging the isolation address. As soon as the isolation address responds it will initiate an election process or join an existing election process and the cluster will return to a normal state.

There’s absolutely no need to manually intervene. HA takes care of all of this for you.

Top VMware/virtualization blogs 2012 voting starts today

Yes, it is that time of the year again…’s voting for the Top 25 Blogs worldwide has started again. I had the honor of placing 1st four consecutive times, but the competition is huge this year with excellent newcomers like Chris Colotti, scripting warriors like William Lam and Alan Renouf and of course my long time rival/friend Chad Sakac.

I am hoping each of you will select the top-10 blogs based on quality, longevity and frequency. (I personally find length of the article irrelevant, content is King!) I did want to list my top 10 articles over the last 12 months:

  1. The vSphere 5.0 – HA Deepdive
  2. Using vSphere Auto-Deploy in your home lab
  3. Multiple-NIC vMotion in vSphere 5…
  4. esxtop
  5. vSphere 5.0: Storage vMotion and the Mirror Driver
  6. vSphere 5.0: What has changed for VMFS?
  7. HA Architecture Series (1 – 5)
  8. “Hacking” Site Recovery Manager (SRM) / a Storage Array Adapter
  9. ESXi 5.0 and Scripted Installs
  10. vSphere 5.0 vMotion Enhancements

The voting is very straight forward and will only take 2 minutes of your time, all you have to do is select your Top 10 favourite VMware related virtualization blog sites and then sort them in your order of preference (ie: 1 – 10) – it’s as easy as that! Don’t wait any longer, cast your vote now!

iBook / Nook? What really?

It took us a while to figure this one out, but finally we managed to create a proper epub version of our book. Converting from Kindle to iBooks / Nook is not easy, but after using multiple tools and manually editing the book using Sigil we managed to create version which was submitted to the iBooks store and Barnes & Nobles a couple of weeks ago. This morning I noticed that the book has been made available. So for all those who have been asking about it, here are the links:

We hope you will enjoy it!

No Jumbo frames on your Management Network! (Updated!)

I was just reading some of the comments posted today and Marc Sevigny, one of the vSphere HA developers, pointed out something which I did not know. I figured this is probably something that many are not aware of so I copied and pasted his comment:

Another thing to check if you experience this error is to see if you have jumbo frames enabled on the management network, since this interferes with HA communication.

This is document here in a note:

To make it crystal clear: disable jumbo frames on your management network with vSphere 5.0 as there’s a problem with it! This problem is currently being investigated by the HA engineering team and will hopefully be resolved.

<Update> Just received an email that all the cases where we thought vSphere HA issues were caused by Jumbo Frames being enabled were actually caused by the fact that it was not configured correctly end-to-end. Please validate Jumbo Frame configuration on all levels when configuring. (Physical Switches, vSwitch, Portgroup, VMkernel etc)</Update>