Yellow Bricks

by Duncan Epping

VMware Cloud Foundation

vSAN File Services and Stretched Clusters!

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As most of you probably know, vSAN File Services is not supported on a stretched cluster with vSAN 7.0 or 7.0U1. However, starting with vSAN 7.0 U2 we now fully support the use of vSAN File Services on a stretched cluster configuration! Why is that?

In 7.0 U2, you now have the ability to specify during configuration of vSAN File Services to which site certain IP addresses belong. In other words, you can specify the “site affinity” of your File Service services. This is shown in the screenshot below. Now I do want to note, this is a soft affinity rule. Meaning that if hosts, or VMs, fail on which these file services containers are running it could be that the container is restarted in the opposite location. Again, a soft rule, not a hard rule!

Of course, that is not the end of the story. You also need to be able to specify for each share with which location they have affinity. Again, you can do this during configuration (or edit it afterward if desired), and this basically then sets the affinity for the file share to a location. Or said differently, it will ensure that when you connect to file share, one of the file servers in the specified site will be used. Again, this is a soft rule, meaning that if none of the file servers are available on that site, you will still be able to use vSAN File Services,  just not with the optimized data path you defined.

Hopefully, that gives a quick overview of how you can use vSAN File Services in combination with a vSAN Stretched Cluster.  I created a video to demonstrate these new capabilities, you can watch it below.

vSAN 7.0 U2 now integrates with vSphere DRS

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One of the features our team requested a while back was integration between DRS and vSAN. The key use case we had was for stretched clusters. Especially in scenarios where a failure has occurred, it would be useful if DRS would understand what vSAN is doing. What do I mean by that?

Today when customers create a stretched cluster they have two locations. Using vSAN terminology these locations are referred to as the Preferred Fault Domain and the Secondary Fault Domain. Typically when VMs are then deployed, customers will create VM-to-Host Affinity Rules which state that VMs should reside in a particular location. When these rules are created DRS will do its best to ensure that the defined rule is adhered to. What is the problem?

Well if you are running a stretched cluster and let’s say one of the sites go down, then what happens when the failed location returns for duty is the following:

  • vSAN detects the missing components are available again
  • vSAN will start the resynchronization of the components
  • DRS runs every minute and rebalances and will move VMs based on the DRS rules

This means that the VMs for which rules are defined will move back to their respective location, even though vSAN is potentially still resynchronizing the data. First of all, the migration will interfere with the replication traffic. Secondly, for as long as the resync has not completed, I/O will across the network between the two locations, this will not only interfere with resync traffic, it will also increase latency for those workloads. So, how does vSAN 7.0 U2 solve this?

Starting with vSAN 7.0 U2 and vSphere 7.0 U2 we now have DRS and vSAN communicating. DRS will verify with vSAN what the state is of the environment, and it will not migrate the VMs back as long the VMs are healthy again. When the VMs are healthy and the resync has completed, you will see the rules being applied and the VMs automatically migrate back (when DRS is configured to Fully Automated that is).

I can’t really show it with a screenshot or anything, as this is a change in the vSAN/DRS architecture, but to make sure it worked I recorded a quick demo which I published through Youtube. Make sure to watch the video!

I joined the Futr Tech Podcast last week, check out the episode here!

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Last week I had the pleasure of joining Chris and Sandesh on the Futr Tech podcast. The episode was just published online, and I wanted to share it with all of you via this blog post. Make sure to watch/listen to the episode and subscribe to the youtube channel or podcast. I’ve been following these guys for a while, and there are some very interesting conversations to check out. (I enjoyed the episode with Bipul Sinha very much.)

You can find them on youtube here, or add them to your podcast app of choice (buzzsprout, spotify, itunes) I had fun, looking forward to some more podcasting in 2021!

What if the disk controller driver included in my vendor’s ESXi image is not on the vSAN HCL?

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Sometimes unfortunately there are situations where a vendor’s ESXi image includes a disk controller driver that is not on the vSAN HCL/VCG (VMware Compatibility Guide). Typically it is a new version of the driver which is supported for vSphere, but not yet for vSAN. In that situation, what should you do? So far there are two approaches I have seen customers take:

  1. Keep running with the included driver and wait for the driver to be supported and listed on the vSAN HCL/VCG
  2. Downgrade the driver to the version which is listed on the vSAN HCL/VCG

Personally, I feel that option 2 is the correct way to go. The reason is simple, vSphere and vSAN have different certification requirements for disk controllers and the vSAN certification criteria are just more stringent than vSphere’s. Hence, sometimes you see vSAN skipping certain versions of drivers, this usually means a version did not pass the tests. Now, of course, you could keep running the driver and wait for it to appear on the vSAN HCL/VC. If however, you hit a problem, VMware Support will always ask you first to bring the environment to a fully supported state. Personally, I would not want the extra stress while troubleshooting. But that is my experience and preference. Just to be clear, from a VMware stance, there’s only one option, and that is option two, downgrade to the supported version!

Top 15 VMworld 2020 sessions to attend

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VMworld 2020 is coming, which means I get to create a list of sessions again which I feel are worth attending. My focus will primarily be on sessions that are hosted by folks of the VMware Cloud Platform Business Unit, which means that the list will be dominated by sessions on the topic of vSAN, vSphere, VCF etc. The key reason for it being of course is that I know most of the speakers on those sessions, and I have attended many of those sessions in the past, so I know what to expect.

I have two sessions accepted this year. The two sessions are:

  • vSAN 7.0: A Platform for both Virtual Machine and Containerized Workloads [HCI1814] – Duncan Epping & Cormac Hogan
  • Change Begins at the End of Your Comfort Zone: My Take 3 Journey [ETPD1043] – Duncan Epping

Make sure to attend these sessions, and if you have any questions, feel free to drop me a note on twitter! When it comes to my top 15 sessions, please note that these are in random order, and also note that if your (or a) session is not listed it doesn’t mean I feel your session isn’t going to be great, it simply means I had too many great sessions to pick from and I somehow had to limit the list. Here we go:

  1. Fast Forward to Future-Ready Infrastructure [HCI3074] by John Gilmartin
    In this BU showcase, John Gilmartin will be discussing where HCI stands today, but more importantly, which direction we are heading towards!
  2. 60 Minutes of NUMA [HCP2453] by Frank Denneman
    Do you want to know everything you ever need to know about NUMA when it comes to vSphere? Make sure to watch this session, it was an instant classic last year, and I am sure it will be again this year!
  3. Storage and Availability Vision [HCP3073] by Vijay Ramachandran and Jayanta Dey
    This is the session where futures are discussed! Vijay and Jayanta will be sharing with you which concepts and functionality VMware is exploring for future releases of our HCI products. Definitely worth attending if you want to get a hint of our roadmap.
  4. The Datacenter of the Future [HCP3004] by Kit Colbert and Pere Monclus
    In this session Kit and Pere are going to discuss the future of the Datacenter. Both Kit and Pere are a CTO for the business unit they work for, so you can expect this session to be forward-looking and discuss the trends VMware is seeing and technologies they expect to become mainstream in the upcoming years.
  5. Datrium-based DRaaS Deep Dive: The What, Why, How of the new VMware DRaaS [HCI2886] by Nabil Quadri and Sazzala Reddy
    As most of you know, VMware recently acquired Datrium. In this session, Nabil and Sazzala are going to dive deep into what their DR as a Service solution brings, how it works, and why you should be watching this space closely!
  6. Extreme Performance Series: vSphere Compute and Memory Schedulers [HCP2583] by Xunjia Lu and Qasim Ali
    I always try to watch 2 or 3 sessions in the Extreme Performance Series, these sessions are always very educational. I have learned something new every single time I’ve attended, or watched, one of these. Do note, this is a deep (as in DEEP) dive typically.
  7. vSAN Technical Deep Dive [HCI1069] by Rakesh Radhakrishnan and Matt Amdur
    Technical deep dives host by engineering and product management are always worth attending in my eyes, and both Rakesh and Matt will for sure deliver what you would expect a deep dive to be.
  8. vSphere Virtual Volumes (vVols): Modernize Your External Storage [HCI1692] by Cody Hosterman and Jason Massae
    If I had to pick two people to tell me all about vVols it would probably be Cody and Jason, these guys understand core storage and vVols inside out, and on top of that understand very well how, and why, customers are implementing it!
  9. The Future of Networking with VMware NSX [VCNC1555] by Bruce Davie and Marcos Hernandez
    A lot has changed in the world of networking the past decade or so, and with IoT and 5G around the corner, it is important to understand how VMware can help you moving into this new era.
  10. vCenter Server 7 Deconstructed [HCP2328] by Emad Younis and Niels Hagoort
    In this session Emad and Niels will be discussing the internals of vCenter Server. How did VMware integrate the Kubernetes effort? How does Lifecycle Manager help you manage your cluster?
  11. HCI Management: Current and Future [HCI1514] by Junchi Zhang
    In this session Junchi will be discussing the future of HCI management. In the last couple of years, this session has always been packed with demos of future functionality, and it has been my favorite the past couple of years for sure!
  12. What’s New in Site Recovery Manager and vSphere Replication [HCI1452] by Cato Grace and Velina Krasteva
    A lot has changed for Site Recovery Manager in the past year, definitely worth getting a better understanding by watching this session!
  13. Deep Dive: Storage for VMware Cloud Foundation [HCI2362] by Kevin Tebear and Ron Scott-Adams
    The question of which storage platform to use with VCF comes up frequently, and in this session Kevin and Ron are going to discuss all the supported protocols and architectures, and they will be providing guidance and best practices around what to use and when/where.
  14. Innovations in vSphere 7 vMotion: Architecture and Performance [HCP1508] by Sreekanth Setty and Yanlei Zhao
    I watched this session last year, and it was very interesting, a lot of in-depth info around the changes introduced and the changes that will be introduced in the future, to further improve the vMotion process!
  15. Inside xLabs and Off-Roadmap Innovation in the VMware Office of the CTO [OCTO2406] by Daniel Beveridge and Chris Wolf
    In the past couple of years Daniel and Chris have been hosting some very interesting sessions, some very fascinating ideas, concepts, and trends were shared, along with potential solutions for these.