Yellow Bricks

by Duncan Epping

Archives for January 2009

VMworld Europe, be there!

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I often get the question where I get my information from. Besides the wealth of information found on the PlanetV12n blogs and the VMware documentation there’s another great source: VMworld. Some go to VMworld just for “networking”, but besides expanding your network you can gather a lot of knowledge during your stay. Not only during your stay, because your vmworld.com account will also give you the possibility to download the presentations. These presentations contain, and especially the deep-dive sessions, in-depth information on the chosen subject.

Just to give you an idea, check this presentation that Rich shared via VM/ETC.com “VI3 TA19, Advanced Log Analysis“. There’s a great section on SCSI Error Strings which might just explain the vmkernel log messages you’ve been seeing(Storagemonitor). Anyway, VMworld Europe 2009, France – Cannes, Be there and Register now!

Old School: Label your Hardware

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So you were used to labelling your hardware with the name of the System running on it. But when running everything virtual you can label your ESX hosts but never know which VM resides at which Server without checking your console and/or vCenter.

Wouldn’t it be cool if you would have a magic Label that updated itself every once in a while. This way one would be able so see within just a glance which VM runs on which host.As you know there’s no such thing as a magic “label”, or maybe there is…

Yesterday I received an email from Nick Weaver(@lynxbat). He emailed me about a very very very cool script he wrote. No this script isn’t going to update your printed label off course. This script displays the VM’s running on your host on the front panel LCD. Most servers these days have frontpanel LCD’s and they can be updated with a couple simple ipmi commands.

Nick wrote an extensive article on how-to create a self updating magic label 🙂 in short:

  1. Install Dell OpenManage and run it on the ESX host (needed for ipmi drivers)
  2. Install ipmitool 1.8.10(SCP over, ./configure, make, make install….)
  3. Run lcd_update.sh script

Now walk over to your Dell server and check the result in the display, isn’t that amazing. Probably one of the most inventive scripts I’ve seen the last few months, it’s simple and gets the job done. Great job Nick, and I’m really curious what you will come up with next.

If I can find a Dell Machine this week I will definitely test it and post a screenshot!
I just received a link to a youtube video that shows it’s actually working!

vimsh, what can I do with it?

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Vimsh(and vmware-vim-cm) is probably one of the worst documented commands out there. At the same time it’s one of the most powerful commands(I know it’s a shell…) out there. You name it and “vimsh” does it. Most of you ran into the “enabling vmotion” from the Service Console problem when first starting out with scripted install. Vimsh solves this:

/usr/bin/vmware-vim-cmd “hostsvc/vmotion/vnic_set vmk0″

As you can see “vimsh” is very powerful, but most of the other command-line stuff can be handled with the “esxcfg-*” commands. Well almost, for instance we talked about enabling autostart in my previous post. According to the KB article you must edit the file “/etc/vmware/hostd/vmAutoStart.xml”. Editing this file can be dangerous, I guess this goes for most ESX configuration files. During the Dutch VMUG I had a short chat with Wil van Antwerpen, Wil told me he was busy documenting the “vimsh” “command” in a wiki. After I published the enabling autostart blog Wil emailed me that this could and should be done with “vimsh”. I fully agree with Wil:

vmware-vim-cmd /hostsvc/autostartmanager/enable_autostart true

This enables the autostart functionality without manually editing the files. But I guess you would like to check if it’s enabled or disabled:

vmware-vim-cmd /hostsvc/autostartmanager/get_defaults

The big question remains, how do I know what I can and can’t do with “vimsh”. Well that’s the main reason for this post, as I said Wil has been very busy documenting “vimsh”. Wil created VI-Toolkit.com. VI-Toolkit.com contains a section on vimsh. Besides the the info that the vimsh command provices Wil added sample code. The sample code can be very usefull, but the search function is even more useful. Searching the vimsh documentation provides you with a fast way to check if a specific configuration action can be scripted with “vimsh”. For instance a search on “vimsh role” returns the following:

* Vimsvc/auth/role add
==== vimsh vimsvc/auth/role_add ==== Usage: role_add roleName [priv0] [priv1] [priv2] [priv3] [priv4]
171 B (24 words) – 14:32, 26 December 2008
* Vimsvc/auth/role permissions
==== vimsh vimsvc/auth/role_permissions ==== Usage: role_permissions roleName
1 KB (118 words) – 22:26, 28 December 2008
* Vimsvc/auth/role remove
==== vimsh vimsvc/auth/role_remove ==== Usage: role_remove roleName [failIfUsed]
123 B (16 words) – 14:34, 26 December 2008
* Vimsvc/auth/roles
==== vimsh vimsvc/auth/roles ==== Usage: roles
7 KB (550 words) – 21:50, 28 December 2008

I guess I can sum up this blog post in just one line:”Bookmark VI-Toolkit.com and add it to your RSS reader!”. Be sure to not miss out on anything regarding “vimsh” or any of the VI Toolkits that Wil be be describing and aggregating source code for. The “vimsh” section alone is already 345 pages large and it will continue to grow even more. Keep up the great work Wil and it was nice meeting you in person!

Check if autostart is enabled from the COS

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I didn’t know this was possible. But you can easily check via the COS if autostarting of VM’s in enabled or not according to this KB article:

  1. Log in as root to your ESX host with SSH.
  2. Open the /etc/vmware/hostd/vmAutoStart.xml file in text editor.
  3. Search for a line that reads:

    <enabled>true</enabled>

  4. If you find the line, the functionality is enabled. If you do not find the line, the functionality is disabled.
  5. If you want to disable autostart for all virtual machines on the host, remove the line.
  6. If you want to enable the functionality, add the line immediately after the line ending with:

    7. <dynamicProperty>

  7. Save your changes and exit.
  8. Restart the management agents on the ESX host:
    service mgmt-vmware restart

Happy New Year

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I just wanted to wish you all a happy New Year! Let’s hope 2009 will be as great as 2008 was. I will try to produce a whole bunch of great articles again! And Yellow-Bricks will have other contributors in 2009 to bring Yellow-Bricks.com to the next level. So keep checking this site for the latest and greatest info! When the first contributor is settled I will give him a proper introduction!