Experts2Experts Virtualization Conference – Vienna May 25th-27th 2012

Posted on May 7, 2012 by workinghardinit

I’m attending and speaking at one the of the best small scale virtualization conferences out there. I’m talking about the Experts2Experts Virtualization Conference (E2EVC) organized by Alex Juschin for many years now. I’ll be speaking at the conference on “Making Sense of RSS, DMVQ, SR-IOV, RDMA and other advanced networking features”. We’ll see where Windows Server 2012 & the new generation of Hyper-V is at in regards to these technologies, how it stacks up against some other solutions and what looks promising. In other words what we are looking at to use in real live once Windows Server 2012 goes RTM.

I have the good fortune to attend some pretty big, impressive & high quality industry events. These are excellent places for networking and getting up to speed with the latest of the greatest form the big vendors and the ecosystem around it. But they are pretty expensive and large scale, so most people are so crazy busy at those you often miss out on some of the interaction, there is just to much going on.

E2EVC is special and adds a different kind if value that goes beyond its low cost. For one, nobody is trying to sell you anything. All attendees and all speakers are IT Pro’s that design, build, work with and support the technologies that are discussed. Hence the name, Expert 2 Expert. It’s a reality check on what are people really using, trying, evaluating. You’ll see what is really hurting us and what really works. An event like this isn’t driven by marketing. It’s driven by interests, passion for technology and even more important from a business perspective the solutions they can and do deliver in real live. This proves that you don’t need to charge premium prices to keep the riff raff out. The fact that 2 days of this conference are in a weekend tells you the attendees are going there with intend and purpose.

The guys & gals attending & presenting are top notch. They don’t look like slick advisers and analysts. It’s all very informal and relaxed. But make no mistake, these people are sharp and at the top of their game. Discussion and interaction is stimulated and lively. The aim is not to breed or create rock star speakers but to get people to share their experiences and knowledge. And here in lies the value. I really commend Alex Juschin for having succeeded in this.

Fixing Hiccups in The SCVMM2008R2 GUI & Database

Posted on May 3, 2012 by workinghardinit

As you might very well know by experience sometimes the System Center Virtual Machine Manager GUI and database get out of sync with reality about what’s going on for real on the cluster. I’ve blogged about this before in SCVMM 2008 R2 Phantom VM guests after Blue Screen and in System Center Virtual Machine Manager 2008 R2 Error 12711 & The cluster group could not be found (0×1395)

The Issue

Recently I had to trouble shoot the “Missing” status of some virtual machines on a Hyper-V cluster in SCVMM2008R2. Rebooting the hosts, guests, restarting agents, … none of the usual tricks for this behavior seemed to do the trick. The SCVMM2008R2 installation was also fully up to date with service packs & patches so there the issue dot originate.

Repair was greyed out and was no use. We could have removed the host from SCVMM en add it again. That resets the database entries for that host en can help fix the issues but still is not guaranteed to work and you don’t learn what the root cause or solution is. But none of our usual tricks worked.We could have deleted the VMs from the database as in but we didn’t have duplicates. Sure, this doesn’t delete any files or VM so it should show up again afterwards but why risk it not showing up again and having to go through fixing that.

The Cause

The VMs were in a “Missing” state after an attempted live migration during a manual patching cycle where the host was restarted the before the “start maintenance mode” had completed. A couple of those VMs where also Live Migrated at the same time with the Failover Cluster GUI. A bit of confusion al around so to speak nut luckily all VMs are fully operational an servicing applications & users so no crisis there.

The Fix

DISCLAIMER

I’m not telling you to use this method to fix this issue but you can at your own risk. As always please make sure you have good and verified backups of anything that’s of value to you

We hade to investigate. The good news was that all VMs are up an running, there is no downtime at the moment and the cluster seems perfectly happy Smile .

But there we see the first clue. The Virtual machines on the cluster are not running on the node SCVMM thinks they are running, hence the “Missing” status.

First of all let’s find out what host the VM is really running on in the cluster and see what SCVMM thinks on what host the VM is running. We run this little query against the VMM database. That gives us all hosts known to SCVMM.

SELECT [HostID],[ComputerName] FROM [VMM].[dbo].[tbl_ADHC_Host]

HostID ComputerName

559D0C84-59C3-4A0A-8446-3A6C43ABF618 node1.test.lab

540C2477-00C3-4388-9F1B-31DBADAD1D8C node2.test.lab

40B109A2-9E6B-47BC-8FB5-748688BFC0DF node3.test.lab

C2DA03CE-011D-45E3-A389-200A3E3ED62E node4.test.lab

6FA4ABBA-6599-4C7A-B632-80449DB3C54C node5.test.lab

C0CF479F-F742-4851-B340-ED33C25E2013 node6.test.lab

D2639875-603F-4F49-B498-F7183444120A node7.test.lab

CE119AAC-CF7E-4207-BE0B-03AAE0371165 node8.test.lab

AB07E1C2-B123-4AF5-922B-82F77C5885A2 node9.test.lab

(9 row(s) affected)

Voila en now the fun starts. SCVMM GUI tells us “MissingVM” is missing on node4.

We check this in the database to confirm:

SELECT Name, ObjectState, HostId
FROM VMM.dbo.tbl_WLC_VObject
WHERE Name = 'MissingVM'
GO

Which is indeed node4

Name ObjectState HostId

——— — ————————————

node4 220 C2DA03CE-011D-45E3-A389-200A3E3ED62E

(1 row(s) affected)

In SCVMM we see that the moving of the VM failed. Between node 4 and node 6.

Now let’s take a look at what the cluster thinks … yes there it is running happily on node 6 and not on node 4. There’s the mismatch causing the issue.

So we need to fix this. We can Live Migrate the VM with the Failover Cluster GUI to the node SCVMM thinks the VM still resides on and see if that fixes it. If it does, great! You have to give SCVMM some time to detect all things and update its records.

But what to do if it doesn’t work out? We can get the HostId from the node where the VM is really running in the cluster, which we can see in the Failover Cluster GUI, from the query we ran above and than update the record:

UPDATE VMM.dbo.tbl_WLC_VObject
SET HostId  = 'C0CF479F-F742-4851-B340-ED33C25E2013'
WHERE Name = 'MissingVM'
GO

We then reset the ObjectState to 0 to get rid of the Missing status. It would do this automatically but it takes a while.

UPDATE VMM.dbo.tbl_WLC_VObject
SET ObjectState = '0'
WHERE Name = 'MissingVM'
GO

After some patience & Refreshing all is well again and test with live migrations proves that all works again.

As I said before people get creative in how to achieve things due to inconsistencies, differences in functionality between Hyper-V Manager, Failover Cluster Manager and SCVMM 2008R2 can lead to some confusing situations. I’m happy to see that in Windows 8 the action you should perform using the Failover Cluster GUI or PowerShell are blocked in Hyper-V Manager. But SCVMM really needs a “reset” button that makes it check & validate that what it thinks is reality.

Failover Cluster Node Names in Upper & Lower Case In Window 2012 with Cluster.exe, PowerShell & GUI

Posted on April 26, 2012 by workinghardinit

Cluster Node Names Can Be Inconsistently Named

A lot of us who build failover clusters are bound to run into the fact that the node names as shown the Failover Cluster Management GUI is not always consistent in the names format it gives to the nodes. Sometimes they are lower case, sometimes they are upper case. See the example below of a Windows Server 2008 R2 SP1 cluster.

Many a system administrator has some slight neurotic tendencies. And he or she can’t stand this. I’ve seen people do crazy things like trying to fix this up to renaming a node in the registry. Do NOT do that. You’ll break that host. People check whether the computer object in AD is lower or upper case, whether the host name is lower or upper case, check how the node are registered in DNS etc. They try to keep ‘m all in sync at sometimes high cost Smile But in the end you can never be sure that all nodes will have the same case using the GUI.

So what can you do?

Use cluster.exe to add the node to the cluster. That enforces the case you type in the name! An example of this is when you’d like upper case node names:
```
cluster.exe /cluster:CLUSTER-NAME /add /node:UPPERCASENODE1
```
Some claim that when you add all nodes at the same time and they will all be the same. But ‘m not to sure this will always work.

Windows 2012

In Windows 2012 PowerShell replaces cluster.exe (it is still there, for backward compatibility but for how long?) and they don’t seem to enforce the case of the names of the node. For more info on Failover Clustering PowerShell look at Failover Clusters Cmdlets in Windows PowerShell, it’s a good starting point.

Don’t despair my fellow IT Pros. Learn to accept that fail over clustering is case insensitive and you’ll never run into any issue. Let it go …. Well unless you get a GUI bug like we had with Exchange 2010 SP1 or any other kind of bug that has issues with the case of the nodes Smile .

If you want to use cluster.exe (or MSClus) for that matter you’ll need to add it via the Add Roles and Features Wizard / Remote Administration Tools /Feature Administration Tools / Failover Clustering Tools. Note that there are not present by default.

On an upgraded node I needed to uninstall failover clustering and reinstall it to get it to works, so even in that scenario they are gone and I needed to add them again.

MSClus and Cluster.EXE support Windows Server 2012, Windows 2008 R2 and Windows 2008 clusters. The Windows Server 2012 PowerShell module for clustering supports Windows Server 2012 and Windows Server 2008 R2, not Windows Server 2008.

For more information see the relevant section at Remote Server Administration Tools (RSAT) for Windows Vista, Windows 7, Windows 8 Consumer Preview, Windows Server 2008, Windows Server 2008 R2, and Windows Server “8” Beta (dsforum2wiki). You’ll have to live with the fact that a lot of documentation still refers to Windows Server 8. As of his post, it’s only been a week that the final name of Windows Server 2012 was announced.

Upgrading Hyper-V Cluster Nodes to Windows Server 2012 (Beta) – Part 3

Posted on April 20, 2012 by workinghardinit

This is a multipart series based on some lab test & work I did.

Part 1 Upgrading Hyper-V Cluster Nodes to Windows Server 2012 (Beta) – Part 1
Part 2 Upgrading Hyper-V Cluster Nodes to Windows Server 2012 (Beta) – Part 2
Part 3 Upgrading Hyper-V Cluster Nodes to Windows Server 2012 (Beta) – Part 3

And we have arrived at part three of my adventures while “transitioning” my Hyper-V cluster nodes to Windows Server 2012. I prefer the term transition as is more correct. We can still not do a rolling upgrade a cluster cluster. We still need to create a new cluster and recuperate the evicted nodes.

I’ll repeat myself here (again) by stating I did not reinstall the evicted nodes but upgraded them. Why, because I can and I wanted to try it out and see what happens. For production purposes I do advise you to rebuild nodes from scratch using a well defined and automated plan if possible. I already mentioned this in Upgrading Hyper-V Cluster Nodes to Windows Server 2012 (Beta) – Part 1

Moving the Storage & Hyper-V Guests

So we stopped Part 2 at a newly created cluster without any storage. That’s what we’ll be taking care of in this part. Let’s recap what we already mentioned at the end of Part 2.

We have several options for storage here. We could assign new storage but we cannot do a Quick Storage Migration between cluster using SCVMM2008R2 but that doesn’t fly as SCVMM2008R2 can’t manage Windows 2012 clusters and I don’t know if it ever will. We can do a good old manual or scripted export to and import from the new storage of the VMs what takes a considerable amount of time. You also need to have the extra storage available.

We can also recuperate the old storage with the VMs still on there. This could get tricky as no two cluster should be able to see & use the storage at the same time. The benefit could be that we can just use the import type in Windows Server 2012 “Register the virtual machine in-place” (use the existing unique ID) and be done with it. We’ll try that one. We’ll still have some down time but it should be pretty fast. It’s only from Windows Server 2012 on that we’ll be able to do Shared Nothing Live Migrations between clusters Smile and live will be good. If you have a SAN you could also use clones to get this job done without less risk. You work on cloned data and keep the original around instead of using that for the process described below.

So how do we approach this?

Since Windows Server 2008 storage & clustering isn’t the pain it could be in earlier version. It’s the disk manager handling all that and it makes live a lot easier. All disks presented to a cluster node are off line to the operating system until you bring it online. Even if it contains data or is presented to another host, whether that is a member of another cluster or a stand alone host. Pretty cool. It also means you can have all your nodes on line during the process. The process of bringing the disk online and, if needed formatting it with NTFS and then adding it to the cluster as storage can be done on just one of the nodes.

As you recall I unplugged the evicted node from the iSCSI storage (you could also disable the ports) before I upgraded it. The entire iSCSI configuration got upgraded perfectly so all I needed to do was plug the iSCSI cables in and the storage appeared offline. My old cluster node was up and running still accessing it. Pretty slick! And great as a demo but you can play it safer. That was fun Smile but perhaps we won’t be that brave in a production environment.

Options

You could decide to bring all LUNS over at once or one at the time. The process is the same. If you do it one by one you’ll have to rely on the above behavior to protect the LUNs against corruption or you can un-present the LUNS remaining on the old cluster from the new cluster so you’ll never have an issue. We’ve done both and it works out rather fine in testing. Windows clustering is really doing it’s best to prevent you from shooting yourself in the foot Smile

Let’s say I go LUN by LUN. Now I can just remove the VMs from the old cluster using the Failover cluster GUI so they are no longer highly available on that node. When I have no more clustered VMs on a CSV LUN I can shut down all the guests in Hyper-V Manager and stop right there.

On the old cluster I remove that LUN from the CSV storage and from the cluster storage. At that moment that LUN is already taken offline for you!

Pardon the silly size but I didn’t have space left to make a realistic screenshot Smile

Great, Windows is protecting us against any possible data corruption! So now I can than un-present the LUN form the old cluster nodes. The next step is to enable the ISCI ports, present that LUN to the new cluster node or nodes (depends on where in the x number of node process you are) or just plug in the cable .

You’ll see the new LUN off line than on the new cluster. We can than make the LUN on line so it will be available to add to the cluster. Just right click that disk and select “Online”.

Right click on storage

Select an disk that’s available to add to the cluster.

Things has gotten a lot simpler with CSV in Windows Server 2012. No more enabling it with a funky warning message that’s well meant but is rather confusing an annoying. You just right click the disk and choose “Add to Cluster Shared Volumes” and that’s it.

And there it is. That disk in our new cluster is ready to use as a CSV.

So we can now us a nifty new capability in Windows Server 2012 Hyper-V: “Register the virtual machine in-place” (use the existing unique ID)

The wizard starts.

Select the folder where your VM or VMs live. yes you can do multiple given that your folder structure allows for this.

It’s found one VM in our folder

We click Next

We select “Register the virtual machine in-place” (use the existing unique ID) and click next.

If something is not right like some forgotten “saved” states you’ll get a change to dump those or cancel the process to deal with it properly before trying it again.

If virtual network names do not match you’ll get the opportunity to set correct that by specifying what virtual switch to use.

If all was well in the first place or after you’ve fixed any issues like the ones demonstrated above you’re good to go. Click finish and enjoy your Windows Server 2012 Hyper-V Guest.

At this point you can already start your VMs. I know that the next step is to make all these VMs highly available but here we have some good news as well. You can now make running VMs highly available. Yeah! They no longer need to be shut down. All this is done via the well know process so I’m not going to walk trough the entire process here. But the screen shot of a making a running VM highly available is worth posting Smile

Working Hard In IT

My view on IT from the trenches