Yellow Bricks

by Duncan Epping

Top yellow-bricks posts of 2010

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My colleague Eric Gray blogged about “VCritical’s” top 10 this morning and I figured why not do the same… here we go:

While many posts from previous years have proven to be evergreen, and among the most heavily trafficked, these are the top posts on Yellow-Bricks published in 2010:

  1. ESXTOP
  2. VMotion, the story and confessions
  3. What’s the point of setting “-iops=1”
  4. VMware vCloud Director
  5. Storage I/O Fairness
  6. vCD Networking – Intro – Part 1
  7. The Resource Pool Priority-Pie Paradox
  8. Limiting your vCPU
  9. Aligning your VMs virtual harddisks
  10. SIOC, tying up some lose ends

My personal favorites:

  1. VMotion, the story and confessions
    I guess I love this one as it isn’t really a tech deepdive but more about how VMware, and in specific Mike Nelson, changed my world and those of many others… Especially the comments make this article a great read!
  2. Re: Maximum Hosts Per Cluster
    This is what I love about blogging, responding to others, voicing your opinion, sharing thoughts / knowledge / expertise… that is what it is all about in my opinion.
  3. ESXTOP
    I love esxtop, there is so much info to be found in esxtop that I never knew where to start. I started documenting some thresholds and by the looks of the stats on this page I wasn’t the only one who needed some guidelines. This page is getting more hits daily than my HA deepdive…

I want to thank everyone for reading yellow-bricks.com and I want to wish all of you a great 2011. See you next year,

Binding a vCloud Director Provider vDC to an ESX Host?

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One of our partners was playing around with vCloud Director and noticed that they could create a Provider vDC and link it directly to an ESX Host. vCloud Director did not complain about it so they figured it would be okay. However it is a requirement for vCloud Director to have DRS. One of the reasons for this being is the fact that vCloud Director leverages resource pools to ensure tenants receive what they are entitled to.

But back to the issue, they created the Provider vDC and went on to create an Org vDC and even that worked fine… Next stop was the “Organization Network. In order to create one you will need to select a network pool at some point and for some weird reason that didn’t work. After some initial emailing back and forth I noticed they didn’t select a cluster or resource pool but an ESX host. After creating a new Provider vDC based on a vSphere Resource Pool all of a sudden everything started working. Although I cannot really say why it is exactly this part that causes an issue, I can tell you that DRS is a hard requirement and not just  a suggestion!

HA role promotion…

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I received a very valid question this week from someone who bought our book. The question was as follows:

On Page 35 it is mentioned that a Secondary Node is not automatically elected as a Primary if a Primary fails. It then goes on to state the conditions under which this does occur, one of these is if the primary node becomes disconnected from the Cluster. When an ESX host fails doesn’t it always end up in the “disconnected” status, if so why isn’t the role transferred?

This one had me thinking for a couple of minutes as it was 6 months ago that I wrote that section, but I knew I tested this back then. When a host fails it will not receive the status “disconnected” but it will receive the status “not responding”. You can disconnect a host by right clicking it and selected “disconnect from cluster”, that would transfer the role to another node… in the case of “not responding” this doesn’t happen as vCenter is unaware of what happened to the host.

Cool Tool: vmktree

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Ever since ESX 2.5 I have always been looking for cool free tools to monitor my hosts. I guess one of the oldest free tools out there is vmktree. Especially in the 2.x timeframe vmktree helped me out solving some weird performance issues. Back then vmktree was still dependent on vmkusage (who remembers that one?) but as of ESX 3.0 vmktree utilizes the api to gather the details needed to plot the graphs.

I lost track of vmktree for a while but when I noticed the announcement this week that 0.4.1 was released I decided to give it a spin again. I logged into my vSphere Management Appliance (vMA) and downloaded vmktree with wget. Installed it following the procedures mentioned in the announcement and literally minutes later I could see the first values coming in. To make sure I had something to show you guys I added a limit of 200MB on a virtual machine. As you know I love esxtop but esxtop are still just “dry numbers” which makes it difficult to see a trend. As you can see in the following screenshot, vmktree makes this trend pretty obvious. (Balloon driver is really active and the size of the balloon is increasing._

Besides memory, of course vmktree has more to offer on both per VM and Host level. For instance on a per VM level you can also see CPU and Storage statistics. On a Host level you can see CPU, Storage and Network. Of course these would include things like Latency, Bus resets, dropped packets, disk space usage… you name it, it is in there.

I know there are a lot of vendors these days offering free monitoring solutions, but the cool thing about vmktree is that it is maintained by just a single person Lars Troen. I can only imagine how much work maintaining a tool like this is. Thanks Lars for helping me out by writing this excellent tool! I would like to ask everyone to give it a try, and of course to provide feedback to Lars so that he can possibly improve vmktree over time.

Looking for PowerCLI skills?

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No need to struggle anymore, just learn PowerCLI from the masters… Luc Dekens and Alan Renouf wrote a book which is available for pre-ordering right now. Most of you probably already know Luc and Alan, but for those who don’t I think I am not exaggerating when I say that these guys are the top PowerCLI experts in the virtualization industry. Both Luc and Alan have a wealth of expertise and know how to explain things in a way that even I can understand it… believe that is an achievement cause I have no affinity with PowerCLI whatsoever. Now, Alan and Luc didn’t do this by themselves they had Arnim van Lieshout, Glen Sizemore and Jonathan Medd helping them out writing the book. Lets not forget their infamous tech editor Stuart “vinternals” Radnidge

VMware vSphere PowerCLI is a must-have tool for any administrator managing VMware vSphere in a Windows environment. Having to repeat vSphere administrative tasks can be time consuming and error-prone, but PowerCLI—created specifically for Windows environments—allows VMware administrators to automate tasks. Written to the latest PowerCLI, this handy guide shows you step by step how to use the PowerCLI cmdlets for daily administration procedures and frequently performed tasks for VMware vSphere X. The reference is organized by vSphere tasks, providing a practical approach to accessing the information you need while you are on the job. Supported by real world examples and no-nonsense instruction, coverage includes installation, configuration, and management of a vSphere environment, management of the virtual machine life-cycle, security, and monitoring and reporting.

While I was scavenging the internet for a screenshot of the cover, which I did not manage to find by the way, I noticed something else. It seems that these 5 guys are literally planning to take over the PowerCLI Community:

It seems that PowerCLIbook.com will primarily be used as a mechanism to offer readers updated versions of scripts, to enable them to ask the authors questions around the book itself and even to download a full Powerpack. Judging by the fact that is hasn’t been formally announced yet I expect the guys are still working on the forum/site.

Anyway, go out and pre-order the book… it is worth it,