Yellow Bricks

by Duncan Epping

VMware

HA Retries

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I am working on a special project at the moment. I noticed something I never realized before and wanted to share it with you guys. When a restart of a VM fails VMware HA will retry this.

The amount of VMware HA retries is configurable as of vCenter 2.5 U4 with the advanced option “das.maxvmrestartcount”. The default value is 5. Pre vCenter 2.5 U4 HA would keep retrying forever which could lead to serious problems as described in KB article 1009625 where multiple virtual machines would be registered on multiple hosts simultaneously leading to a confusing and inconsistent state.(http://kb.vmware.com/kb/1009625)

Important to note is that HA will try to start the virtual machine on each of the hosts in the affected cluster, if this is unsuccessful the restart count will be increased by 1. In other words, if a cluster contains 32 hosts HA will try to start the virtual machine on all hosts and count it as a single try. Something I definitely never realized and something that definitely is worth knowing.

Changing the directory of your vSphere vCenter log files

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Something that a lot of people haven’t looked in to or just don’t think about is relocating the log files of vCenter, I wrote a short article 2 years ago and thought it was time to reiterate it. By default (Windows 2003) log files are stored in “C:\Documents and Settings\All Users\Application Data\VMware\VMware VirtualCenter\Logs”, and for Windows 2008 log files are stored in “C:\ProgramData\VMware\VMware VirtualCenter\Logs”.

As you can imagine the C:\ partition is not the ideal place for storing log files. I would personally recommend to use a separate drive for logfiles so avoid it from flooding any OS or Program related drives. You could pick a small size based on the expected log size and if needed increase the amount of logs that are stored and the size of the log file.

Changing this is pretty simple. Open “vpxd.cfg” and add the following line in between <log> and </log>

<directory>D:\VMware\Logs</directory>

Changing the amount of log files stored and the size is also pretty basic, in this example vCenter will store 10 logfiles which are max 10MB each:

<maxFileSize>10485760</maxFileSize>
<maxFileNum>10</maxFileNum>

Keep in mind that you will need to restart the vCenter Service after these changes before they take effect!

Creating a VMware Converter Appliance

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I was playing around with VMware Converter and thought it would be cool to create a VMware Converter Appliance. I can’t put this up for download, yet, but I can describe how to build your own appliance. I will use Novell’s Suse Studio to create a thin Linux VM that contains only the necessary bits and pieces.

  • Go to susestudio.com and open an account
  • Click “Create New Appliance”
  • Select “GNOME Desktop” and click “Create Appliance”
  • Change the name of the appliance to something that makes a bit more sense…
  • I would personally add “File Roller” and “GCC” so that you can actually open archives from the GUI and make modules, which is need to install VMware tools.
  • Go to the  “Configuration Tab” and click on “Appliance”
  • Increase the memory to 1024MB for a better running appliance
  • Download VMware Converter Standalone for Linux and add it as a file in the “Overlay Files” tab
  • When uploading is finished select a folder where the tar.gz file should be extracted, I picked “/vmwconverter”
  • Click on the “Build” Tab and wait for it to complete

It’s as easy as that! With SUSE you have the option to Test Drive it and make changes to the image while test driving it. I would recommend to just download it and install VMware Converter while running the VM with VMware player. Or you could import it with vCenter and run it on an ESX host. This way you can also install VMware tools immediately.

  • Open the VMX file with VMware Player
  • Install VMware Tools:
    Right click VM “install VMware tools”
  • Open a terminal session within the VM and type: 
    cd /media/VMware Tools
tar -C /tmp -xvf <VMware Tools File>
/tmp/vmware-tools-distrib/vmware-install.pl

    Agree with all the defaults…

  • Now to install VMware Converter open a terminal session and do the following: 
    cd /vmwconverter/vmware-converter-distrib
    ./vmware-install.pl

    Use all the defaults!

  • You can add an icon to the desktop by right clicking the desktop and selecting “Create Launcher”
  • Select “/usr/bin/vmware-converter-client”
  • And add the correct icon! (/usr/share/icons/vmware-converter.png)

Now your appliance is good to go and can be used everywhere in your virtual infrastructure. I would recommend making it a template or vApp and deploy it multiple times when doing many parallel migrations!

Impact of decisions…

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I’ve been conducting VCDX Defense Interviews for a while now. Last week in Las Vegas during PEX something struck me and I guess this post by Frank Denneman is a good example…

On a regular basis I come across NFS based environments where the decision is made to store the virtual machine swap files on local VMFS datastores. Using host-local swap can affect DRS load balancing and HA failover in certain situations. So when designing an environment using host-local swap, some areas must be focused on to guarantee HA and DRS functionality.

Every decision you make has an impact on your design/environment. What does a decision exactly impact? In most cases every decision impacts  the following:

  1. Cost
  2. Availability
  3. Performance

In the example Frank wrote about (see quote) a decision which clearly had an impact on all three. Although at the time it might have been a best practice the decision to go along with this best practice still had an impact on the environment. Because it was a best practice this impact might not have been as obvious. But when listed as follows I hope you understand why I am writing this article:

  • Costs – Reduced costs by moving the .vswp file to local disks.
  • Performance – VMotion performance is effected because .vswp files need to be copied from HOST-A to HOST-B.
  • Availability – Possibly less availability when the amount of free disk space on local VMFS isn’t sufficient to restart VMs in case of disaster.

As you can see a simple decision has a major impact, even though it might be a best practice you will need to think about the possible impact it has and if this best practice fits your environment and meets your (customer) requirements. Another great example would for instance be LUN sizing. So what if I would randomly pick a LUN size. Lets say 1TB:

  • Cost – As the average VM size is 35 GB, I want a max of 20VMs on a datastore and I need 20% of overhead for vswp files and snapshots I end up with max usage of 840GB. Added overhead: 160GB!
  • Availability – Although the availability of the datastore will be unaffected the uptime of your environment might change. When a single datastore fails you will lose 1TB worth of data. Not only will you lose more VMs, restoring will also take longer.
  • Performance – Normally I would restrict the LUN size to reduce the amount of VMs on a single datastore. More VMs on a datastore means more higher possibility of SCSI reservation conflicts.

The VCDX certification is not about knowing all the technical details, of course it is an essential part of it, it’s about understanding the impact of a decision. It’s about justifying your decision based on the impact it has on the environment/design. Know the pros / cons. Even if it is a best practice it might not necessarily apply to your situation.

VMware Partner Exchange 2010

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I attended VMware Partner Exchange this week in Las Vegas. I must say I was impressed. To be completely blunt; I wasn’t impressed with Vegas. Vegas is definitely not my cup of tea. I love a bit of “history” and Vegas hardly has any. Give me San Francisco, New York, Boston or any other city anytime!

I do however was impressed with Partner Exchange. From a logistics standpoint PEX was well organized so my compliments to the organization. The labs, the sessions, the workshops… I wish I could have joined any of these. I’m not complaining though as being part of the VCDX Panel is also a great experience. Seeing the creative solutions people come up with is a learning experience for me as well. Some people have a different view on a concept or solution and this also gives me food for thought. Another thing what I love about being part of the panel is making people think about their own design. I can’t say much about the interviews I conducted though as the NDA police would kill me. I hope to see some of you who are taking the defense in Munich!

I did manage to see the keynote by Steve Herrod by the way. I was impressed with all the insights Steve gave in terms of upcoming products, brand new projects and even a couple tech previews. I am looking forward to the upcoming version of VMware View and a new project which I can’t disclose as the VMware NDA Police would again kill me. I am also looking forward to start using Zimbra.

Especially “Zimlets” seem to be really powerful. Zimlets are basically hook-ins for your email/colaboration tool. A good example would be an Oracle plugin. When an email for instance contains a PO number the PO number will appear as a link to the PO system. But not only a link, when hovering over the link a pop-up will appear with for instance the total amount for the PO and the approval status.

Other upcoming new features that were revealed are IO DRS, Memory Compression and a new View management interface. I recommend reading some of the other blog posts on this topic as there is a lot I can’t write about:

And by the way; Congrats Frank and Andrew Mitchell for becoming VCDX 029 and 030!