Maintenance Mode in Hyper-V 2008 R2 is not what you think it is....

If you have been working with VMware in the past, probably you know what a virtualisation hypervisor should behave when in "maintenance mode" right? meaning the server should be in a state that no virtual machines are allowed to migrate to or have new virtual machines being placed on the server. After working with Hyper-V 2008 R2 for the first time, I made the mistake of "assume" that the maintenace mode is the same in Hyper-V as in VMware, oh boy, was I ever wrong!!!!

We have a hyper-v host that is having some issue with virtual machine networking, so we put it in "maintenance mode" thinking of dealing with it later. The next day, few virtual machines magically migrated to the hyper-v host in maintenance mode and lost network connection!!!! What the £*&^$*?!?!?!?... confused and puzzled, we did some test and tried to manually "live migrate" a vm to the host in Maintenance mode, and we got an error... OK, so it's the system automatically migrate virtual machines to the host.

Did some google search, and also Microsoft verifid that "Hyper-V 2008 R2 maintenance mode is a bit 'funny', here's what you need to do to guarantee no virtual machines gets migrated to a Hyper-V 2008 R2 host:

1) in SCVMM console, right click the host and select "start maintenance mode"
2) in Failover Cluster Manager console, right click on the host and select "Pause"

Turns out, without "pausing" the node in the MS Failover cluster, even though the host is in "maintenance mode" from SCVMM's point of view, it is still part of the Cluster and virtual machine can still be migrated to the host!!!!

So, a word of caution, if you ever decide to do some patching or updating on your Hyper-v host, make sure you also "pause" the node in Failover Cluster manager, to prevent virtual machines being migrate to a hyper-v host that you are doing some patching on....

Microsoft has confirmed that this "feature" has been fixed in SCVMM 2012, so when you do put a host in maintenance mode, it actually automatically "pause" the cluster node so no virtual machine can be migrated to the host... phew.... what a relief.... that's if you continue to use Hyper-v... I've been working with VMware product since 2005 when ESX2.5/GSX is the coolest thing I've seen so I might be a bit biased towards VMware, but the functionality and stability speak for themselves and personally I think Hyper-V 2008 R2 is just not quite on the same level as vSphere. Maybe Hyper-V 3 is better (they better be!), but I have to try it first before I can comment on it. :)

Keep on virtualizing!

Going to London VMUG May 17, 2012!

Just registered for the upcoming London VMUG on May 17th, 2012. I enjoyed it quite a lot going there last time in January earlier this year and met with lots of great people who are passionate about virtualization especially VMware technology. The people who organized the event on their own time for all of us deserves a round of applause! The event detail is http://www.vmug.com/e/in/eid=429. Get registered if you don't want to miss it. There will be a lot of exciting and interesting sessions I am pretty sure and I am really looking forward to be there again. Great thanks to my employer for also supporting us keeping in touch with the industry events like this! :) I will try to put an update on things I take away from the event afterwards (for things we are allowed to blog about of course :)

ciao! and thanks for reading as always!

My Journey to VCAP 5 - Part 1

I am starting this thread to highlight my preparations for VCAP-DCA5 and VCAP-DCD5 exams. I will be writing about things I've learned along the way and share any tips with all of you who is going on the same journey shortly. I think it's never about the result, it's the things we learnt along the way that really counts and helps us to be a better VMware guy :) LOL

Here's the general Plan:

1)Build vSphere 5 Home Lab --- DONE!
2)Pass VCP --- DONE!
3)Pass VCAP-DCD5 --- waiting for official exam blueprint and exam to be released
4)Pass VCAP-DCA5 --- waiting for official exam blueprint and exam to be released
5)Prepare for VCDX5

At the moment, I am gathering study materials for my VCAP-DCD 5 exam, once I have them, I will post them here to share. There are quite a lot of other good blogs out there already listing pretty much same thing which I will also include to give you a one stop shop for studying materials.

Stay Tuned!

Fix for VM crashes during Hyper-V Live Migration

Not that I am a Hyper-V expert or anything since I've been a big fan of VMware and has been doing VMware implementation since 2005, just want to put this out there as I got a chance to play with Hyper-V a little bit now just to see exactly why VMware is more stable and better than Hyper-V in so many ways, R2 or not!:

Check this link out: http://support.microsoft.com/kb/2636573

FIX: The guest operating system may crash when you perform a live migration of Hyper-V virtual machines in a Windows Server 2008 R2 environment and ofcourse as you may have guessed, the fix is.... .... .... ... apply this windows update!!!

oh well, if you are running Hyper-V R2 and have issue with this, here you go.

2 more updates to fix things that simply patched together to make it work "just as" some vSphere features.

http://support.microsoft.com/kb/2511962"0x000000D1" Stop error occurs in the Mpio.sys driver in Windows Server 2008 R2
http://support.microsoft.com/kb/2460971MPIO failover fails on a computer that is running Windows Server 2008 R2

VMware's VMkernel has been built from ground up with virtualization in mind to provide most efficient, stable and best performance features to underlying virtual machines, but I don't think I can say the same thing for Microsoft Hyper-V. The more I look at Hyper-V, the more I am convinced about VMware solutions (not that I am not convinced before :) )

Happy Virtualizing folks!

My VCP5 Experience

I have just got back from my VMWare VCP510 exam. I did it at Global Knowledge in central London. Just want to put down some thoughts and hopefully can help someone out there who is still preparing for this exam.

Overall, I think the exam experience is quite positive, although I was nervous as hell! I arrived at the test centre about 1 hour before it started (as my lovely wife always jokes about me being super on time just like a German lol). It calms me down knowing I will not be late by sitting down across the street in a starbucks sipping my soya Latte looking through the exam blueprint once more while listening to some Jack Johnson song. Went over to the test centre 15 minutes before the exam starts, got my picture taken, signed few papers and finally sit down in front of the exam computer. I recommend doing the survey at the beginning because it gets me into the reading mood. The time is quite tight as you have 90 minutes to go through 85 questions but I managed to have about 10 minutes at the end of the exam to review a few that I am not sure of.

Without breaching my NDA, let me give you some advice on passing the exam.
1) Build a Lab!!! After experiencing first hand, I realized after the exam how valuable my home lab has been towards me passing this exam. (Check out my previous blog about my home lab). Try everything you can possibly can on your lab, enable/disable different features to see the difference it does to your cluster, VMs, hosts etc. Deploy as many vSphere components as you can such as vCenter Server Appliance, vApps, vDR 2.0, Web client. Click through anything you can click on vSphere client GUI to familiar yourself with where things are and different ways of doing the same task.

2) Have the VCP5 Exam Blueprint with you at all time. Read through them and all the recommended documentations.

3) Make up as many scenarios as possible and try it out in your lab!! During the exam, I got few questions that I actually tried myself in my lab just to see how things work and I was really happy to see those questions :) Things that I've tried in my lab:
- create different types of virtual vSphere hosts i.e. ESXi 4.1 and ESXi 5 to see differences- create virtual iSCSI (OpenFiler) targets and NFS (OpenFiler) shares to see the different features of each type of storage. Make sure you know the differences between VMFS3 and VMFS5!
- create vSS and vDS to see the different settings, create port groups, add/remove vmknics to see the effect, etc, etc, etc.

4) Take notes as you practice, so you have a summary of things to review before the exam, helped me a lot as I tend to forget about things fairly quickly unless I do it few times. (getting old...)

5) Take your time and read details when you install ESXi 5.0, vCenter Server, vSA, vDR etc as the installation process actually gives you a lot of valuable informations. When you click through while using vSphere client, read any messages, warnings given by vSphere client, lots of good information on there.

5)IF you choose to use any of the brain dump sites which I don't recommend doing as they are misleading and might waste lots of your precious time, do not take anything for granted and verify yourself and DO NOT try to remember any of the answers they give you. It's still a heated debate on if it's right to use these brain dump sites so I won't get into it too much. It's your own choice. Do it in your own lab as it will be come your own knowledge.

6)Sleep well and relax before the exam.

7)Time management during the exam: I kept myself from spending way too much time on a question, if it is a multiple choice, I use elimination first and most of the time, you can narrow your answers down a lot. Personally I try not to change any answers I put down before as most of the time your first answer is the correct one.

8) Read blogs about other people's VCP 5 experiences/tips/guidelines helped me a lot just to see what to expect during the exam, the following are the ones I read and I highly recommend them:

Simon Long - The SLOG
Scott Vessey
TheSaffaGeek

9) Couple of great books that you might have already know about would help you with VCP and future VCAP/VCDX preparation:

vSphere 5 Clustering Techinical Deepdive by Duncan Epping/Frank Deeneman
Mastering VMware vSphere 5 by Scott Lowe
VMware vSphere PowerCLI Reference: Automating vSphere Administration by Luc Dekens, Alan Renouf, Glenn Sizemore and Arnim van Lieshout

10) Google is your friend!!!

Hope it helps you even a little bit by reading this post. Good luck in your exam and most importantly have FUN!

My vSphere 5 Home Lab Setup - Feb 2012

This is my first blog... ever! believe it or not. One of the reasons I decided to start blogging is to share some of my experience with everyone who is interested in Virtualization technology. Few weeks ago, I have finally decided to purchase some proper home lab hardware for a better vSphere 5 lab to prepare for my VCP5 exam. (say good bye to the Workstation 8 virtual lab on my laptop :) )

Here's a list of hardware I have in my lab:

Hardware:
3 x HP N40L Micro Server, 8GB RAM, 2xAMD Turion II 64bit 1.5GHz, 250GB SATA II, 1GbE onboard NIC ( 3 more PCIe Intel 1GbE cards on the way)
1 x 8 Ports non-managed 1GbE switch
1 x HP laptop to access and manage the lab
3 x 2GB USB sticks (to install and boot my ESXi5.0 hosts from)

Software:
ESXi5.0 installable iso - download from VMware website
vCenter Server 5 installation iso - download from VMware website
Windows Server 2008 R2 SP1 ISO - download trial version from Microsoft website
UNetbootin - Free Windows application to make bootable USB drives

Shared Storage:
OpenFiler version - free download from OpenFiler website

Physical Setup:
ESXi 5.0 will be installed onto the USB drive for each N40L Micro Server and booting off the USB drive. Windows domain controller/DNS/DHCP and vCenter Server 5 will be installed as 2 virtual machines. OpenFiler will be installed as a virtual machine on one of the Microserver utilizing the local hard drives to provide shared iSCSI storage.

Since each HP Microserver comes with a 250GB SATA II drive, I put all 3 x 250GB drives in one of the Micro Servers. ESXi 5.0 server will use these drives as local datastores, then virtual disks will be added to the OpenFiler VM to aggregate these virtual disks together to provide iSCSI LUNs for these 3 ESXi 5.0 hosts as shared storage to provide DRS, HA, VMotion, SVMotion features.

Originally I set up one of the micro servers as a physical NAS box using FreeNAS version 7, but there is some networking issue with that version and network keeps dropping so I kept losing connections to my VMs! In a hurry to setup my vSphere 5 lab environment, I made a decision to use OpenFiler as a VM. Just to let you know that there are many other alternative ways of setting up the shared storage.

Here's my overall lab setup steps:
1) Burn VMware-VMvisor-Installer-201111001-504890.x86_64.iso onto a DVD, boot HP Microserver with the vSphere 5 installation DVD (the USB drive is also connected to the server)
2) Follow the prompt on screen and install ESXi 5.0 onto the USB drive
3) Configure the ESXi 5.0 server with static IP, DNS, Host name, Password etc
3) Connect via a web browser to the installed ESXi 5.0 and download the vSphere client
4) Connect vSphere client to the newly installed ESXi 5.0 server and start building Domain controller VM and vCenter Server and OpenFiler VMs
5) At the same time, follow the same step 1) and 2) to build the other 2 ESXi 5.0 hosts
6) Configure vSphere Cluster settings
7) Configure OpenFiler with iSCSI targets
8) Configure software iSCSI adapters on all ESXi hosts and connect to the OpenFiler targets
9) Now I have a fully functional vSphere 5 home lab to play with.

This is a very generic view of how the lab is setup. I will be posting some detailed steps and how I configured the lab to use for specific features and what kind of tests I setup to review all the new features of the great vSphere 5.0.

Stay Tuned! More to come.