Yellow Bricks

by Duncan Epping

Various

Black Friday Gift: Free copy of the vSphere 6.7 Clustering Deep Dive, thanks Rubrik (ebook)

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Many asked us if the ebook would be made available for free again. Today I have the pleasure of announcing that Frank, Niels and I have worked once again with Rubrik and the VMUG organization to make the vSphere 6.7 Clustering Deep Dive book available for free! Yes, that is 0 USD / EURO, or whatever your currency is. As the book signing at VMworld was wildly popular, which resulted in the follow up discussion about the ebook.

You want a copy? All that we expect you to do is register on Rubrik’s website using your own email address. Anyway, register and start your download engines, pick up a fresh copy of the vSphere Clustering Deep Dive here!

vSAN 6.7 U1 Deep Dive book coming soon!

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Cormac and I decided to update the vSAN Essentials book. We added a whole bunch of extra info and also decided to rebrand it. “Essentials” did not really cut it, it is much more than that. Considering I just finished the Clustering Deep Dive with Frank and Niels, we figured this could be a nice addition to that series, complementing both the Host Deep Dive as well as the Clustering Deep Dive. We’ve received all the feedback from our reviewers, Frank Denneman and Pete Koehler, and spend various evenings digesting and processing it. Now it is just a matter of adding the foreword to the book, and then we can simply press: Publish. Hopefully, within 2 weeks, I will have a new article that details how you can buy the book!

The plan is right now to release the paper copy and the ebook at the same time, we will link the books, so those who buy the paper copy can buy the ebook at a discounted price. We will also make sure the ebook is priced very attractive, as we feel it should be the format of choice for everyone!

Audio stops working on MAC / OSX

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I have this issue where my sound / audio just stops working on my Mac / OSX. Very annoying, and as I find myself searching for the command every time I have this issue I figured I would simply drop it on my blog as a reminder, much easier to find, at least for me. How do I get my audio working again? Well I simply open a terminal and kill the service responsible for it. It is then auto restarted and it starts working again (you can also kill it through the UI):

sudo killall coreaudiod

I have this problem in OSX 10.14.1, but also had it in 10.14 and 10.13.x. if anyone knows how to solve the problem please leave a comment!

ESXi on ARM/Raspberry Pi for vSAN Witness purposes or for?

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I was just catching up on a couple of VMworld sessions. One session that stood out to me was most definitely once again the session by Chris Wolf and Daniel Beveridge. I am not going to write up a full coverage of it, as it is mostly very similar to the session they did in the US which I posted about here.

However, what is interesting in the European edition is that Regis Duchesne comes up on stage after about 38 minutes in and he starts discussing and demoing ESXi on ARM, but more impressively ESXi on top of a Raspberry Pi. Note that these machines have very limited memory (1GB) and little CPU (64-bit SoC @ 1.4GHz) resources, and are low powered! Gotta love an intro as well that includes “been at VMware for about 20 years”.

Very interesting to see that Regis and the team managed to get ESXi booting on an RPI 3b, but also that it only uses about 500MB of the memory, which would leave room to boot one VM as Regis points out if you are lucky. One example of a use case is to use this machine as a physical vSAN Witness host for 2 host configurations. This was the immediate use case I had in mind as well for this!

Regis also mentions the option to run 1 VM on an RPi3, but you could, of course, have multiple RPi’s running and connect them using a 1GbE switch so the VMs can communicate with each other, you could even create a cluster and move VMs between RPi’s when you are doing maintenance at the edge. Or even more VMs could potentially run on an RPi and you could use it as an IoT gateway. As Regis points out, what is great about ESXi is that it already provides isolation and QoS for VMs, which ensures that all apps running on an IoT gateway would get their fair share of resources. (Eliminate the noisy neighbor problems) Note that this is a project and very much at an alpha stage, nowhere close to being available for customers or partners, but as Regis points out… if you are a customer or partner doing things at the edge and interesting in this please let us know. The team is looking for design partners to better understand the different use case, to ensure they build something which can be useful for customers! (You can leave a comment here, let us know what you are looking to do with it and I will connect you with the right folks.)

HA Futures: Admission Control – Part 2 of 4 – (Please comment, feedback needed!)

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Admission Control is always a difficult topic when I talk to customers. It seems that many people still don’t fully grasp the concept, or simply misunderstand how it works. To be honest, I can’t blame them. It doesn’t always make sense when you think things through. Most recently for Admission Control we introduced a mechanism in which you can specify what the “tolerated performance loss” should be for any given VM. This isn’t really admission control unfortunately as it doesn’t stop you from powering on new VMs, it does, however, warn you if you reach the threshold where a host failure would lead to the specified performance degradation.

After various discussion with the HA team over the past couple of years, we are now exploring what we can change about Admission Control to give you more options as a user to ensure VMs are not only restarted but also receive the resources you expect them to receive. As such, the HA team is proposing 3 different ways of doing Admission Control, and we would like to have your feedback on this potential change:

  • Admission Control based on reserved resources and VM overheads
    This is what you have today, nothing changes here. We use the static reservations and ensure that all VMs can be powered on!
  • Admission Control based on consumed resources
    This is similar to the “performance degradation tolerated” option. We will look at the average consumed CPU and Memory resources, let’s say past 24 hours), and base our admission control calculations on that. This will allow you to guarantee performance for workloads to be similar after a failure.
  • Admission Control based on configured resources
    This is a static way of doing admission control similar to the first. The only difference is that here Admission Control will do the calculations based on the resources configured. So if you configured a VM with 24GB of memory, then we will do the math with 24GB of memory for that VM. The big advantage, of course, is that the VMs will always be able to claim the resources they have assigned.

In our opinion, adding these options should help to ensure that VMs will receive the resources you (or your customers) would expect them to get. Please help us by leaving a comment/providing feedback. If you agree that this would be helpful then let us know, if you have serious concerns then we would also like to know. Please help shape the future of HA!