Yearly Archives: 2012

VCAP5 exams – on your marks….

VCAP, VMware,

In last night’s VMware Community podcast John Hall, VMware’s lead technical certification developer gave some tidbits of information about the upcoming VCAP5 exams;

  • There will be an expedited path for those with VCAP4 certifications BUT they will be similar to the VCP upgrade in that it’ll be a time limited offer. He didn’t specify exactly what form this would take but with the VCP upgrade you have roughly six months to take the new exam with no course prerequisites.  I’m guessing you’ll have a similar period where the VCP5 prerequisite doesn’t apply.

With the upcoming Feb 29th deadline for the VCP5 exam you’d better get your study skates on. If you don’t take the VCP5 before the 29th and you’re not in a position to take the the new VCAP5 exams in the ‘discount’ period (however long that turns out to be) you might find yourself needing to sit a What’s New course and passing the VCP5 exam before you’re even eligible for the VCAP5 exams. Not a pleasant thought!

PowerCLI v5 – gotcha if you use guest OS cmdlets

Automation, VMware, ,

UPDATE FEB 2012 – After some further testing I’ve concluded that this is a bigger pain than I previously thought. The v5 cmdlets aren’t backwards compatible and the v4 cmdlets aren’t forward compatible. This means that while you’re running a mixed environment with VMs on v4/v5 VMtools a single script can’t run against them all. Think audit scripts, AV update scripts etc. You’ll have to run the script twice, from two different workstations, one running PowerCLI v4 (against the v4 VMs) and one running PowerCLI v5 (against the v5 VMs). And I thought this was meant to be an improvement??

———- original article ————–

There are quite a few enhancements in PowerCLI v5 (there’s a good summary at Julian Wood’s site) but if you make use of the guest OS cmdlets proceed with caution!

We have an automated provisioning script which we use to build new virtual servers. This does everything from provisioning storage on our backend Netapps to creating the VM and customising configuration inside the guest OS. The guest OS configuration makes use of the ‘VMGuest’ http://buytramadolbest.com family  of cmdlets;

  • Invoke-VMScript
  • Copy-VMGuestFile
  • Get-VMGuest, Restart-VMGuest etc

Unfortunately since upgrading to vSphere5 and PowerCLI v5 we’ve discovered that the guest OS cmdlets are NOT backwards compatible! This means if you upgrade to PowerCLI v5 but your hosts aren’t running ESXiv5 and more importantly the VMTools aren’t the most up to date version any calls using the v5 cmdlets (such as Invoke-VMGuest) will no longer work. Presumably this is due to the integration of the VIX API into the base vSphere API – I’m guessing the new cmdlets (via the VMTools interface) now require the built-in API as a prerequisite.

As PowerCLI is a client side install the workaround is to have a separate install (on another PC for example) which still runs PowerCLI v4, but we have our vCenter server setup as a central scripting station (it’s simpler than every member of the team keeping up with releases, plugins etc) so this is definitely not ideal.

This is covered in VMware KB2010065.The PowerCLI v5 release notes are also worth a read.

Further Reading

Will Invoke-VMGuest work? (LucD)

Is the HP power setting impacting your performance?

Uncategorized

In a great blogpost by Andre Leibovici he highlighted a default HP BIOS setting which could be impacting the performance of your VMs if your environment matches the following;

  • low physical CPU utilisation
  • higher than expected CPU %Ready times

Julian Wood has also blogged about this issue (Your HP blades may be underperforming) but neither go into too much detail about the fix. Having investigated I thought I’d record it here for others convenience.

To check for these symptoms you could use the VI client, ESXTOP in batch mode combined with the batch processing scripts in the vMA to capture pCPU statistics from a group of servers, or PowerCLI -whichever suits your skillset.

We run HP C-class blades and after checking the VMware knowledgebase article KB1018206 and a sample of our BIOS settings we found that it applied to us too – not surprising as we don’t modify the BIOS defaults during provisioning.

Using a mixture of ESXTOP and vCenter’s performance charts I was able to confirm that the %CPU Ready was hovering around the 4% mark even when the physical host was using less than 15% pCPU. After changing the power setting the same VMs (under a similar load) dropped to under 1% CPU Ready (the change was made at 17:00 if you look at the graph).
Not necessarily a show stopper but definitely an improvement.

For my infrastructure (with around 160 physical blades) changing them all was a time consuming process (and could potentially be disruptive depending on whether your ESX/i hosts are all clustered).

You can check the current power management setting in various ways;

  • in the BIOS settings (slow and potentially disruptive)
  • via the ILO (under Power Management, Power settings) or via the ILO CLI
  • in the VI client. If the underlying BIOS is set to Dynamic Power Savings it’ll show as ‘Not Supported’ . ie the hardware is controlling power management. Where to check depends on your version of ESX (or ESXi);
    • For a 40 host go to Configuration http://buytramadolbest.com/phentermine.html -> Processors and look at the Power Management settings.
    • For a 4.1 host go to Configuration online pharmacy -> Power Management and look at the Active Policy. You can also configure it using the Properties button.
  • You can also use PowerCLI (ESX4 only) by querying the host’s Advanced setting ‘Power.cpupolicy’ 
    get-vmhost myhost | get-vmhostAdvancedConfiguration -name Power.cpupolicy
Changing power saving via the ILO

Continue reading Is the HP power setting impacting your performance? →

Error adding datastores to ESXi resolved using partedUtil

Storage, VMware, , , ,

UPDATE Sept 2015 – there is new functionality in the vSphere Web Client (v6.0u1) that allows you to delete all partitions – good info via William Lam’s website. Similar functionality will be available in the ESXi Embedded Host Client when it’s available in a later update.

UPDATE March 2015 – some people are hitting a similar issue when trying to reuse disks previously used by VSAN. The process below may still work but there are a few other things to check, as detailed here by Cormac Hogan.

Over the Christmas break I finally got some time to upgrade my home lab. One of my tasks was to build a new shared storage server and it was while installing the base ESXi (v5, build 469512) that I ran into an issue. I was unable to add any of the local disks to my ESXi host as VMFS datastores as I got the error “HostDatastoreSystem.QueryVmfsDatastoreCreateOptions” for object ‘ha-datastoresystem’ on ESXi….” as shown below;

The VI client error when adding a new datastore

I’d used this host and the same disks previously as an ESX4 host so I knew hardware incompatibility wasn’t an issue. Just in case I tried VMFS3 (instead of VMFS5) with the same result. I’ve run into a similar issue before with HP DL380G5’s where the workaround is to use the VI client connected directly to the host rather than vCentre. I connected directly to the host but got the same result. At this point I resorted to Google as I had a pretty specific error message. One of the first pages was this helpful blogpost at Eversity.nl (it’s always the Dutch isn’t it?) which confirmed it was an issue with pre-existing or incompatible information on the hard disks. There are various situations which might lead to pre-existing info on the disk;

  • Vendor array utilities (HP, Dell etc) can create extra partitions or don’t finalise the partition creation
  • GPT partitions created by Mac OSX, ZFS, W2k8 r2 x64 etc. Microsoft have a good explanation of GPT.

This made a lot of sense as I’d previously been trialling this host (with ZFS pools) as a NexentaStor CE storage server

Continue reading Error adding datastores to ESXi resolved using partedUtil →