I noticed an excellent blog by William Lam not too long ago, which discussed how to bring up VMware Cloud Foundation 5.x on a single box for home labs. William created a Github page that goes over the whole process, and provided all the tweaks and scripts needed to get it done. I wanted to discuss this process with William, as I believe many folks in the VMware/Broadcom community will be interested in deploying this at home, or at work, to go through that full VCF experience but without needing a larger lab environment. You can listen to the episode on Spotify (bit.ly/43WFSpA), Apple (bit.ly/4jqbYyx), or any other podcasting platform. Or simply use the embedded player below! Thanks William, for a fantastic episode.
VMware Cloud Foundation
Does vSAN support a Franken cluster configuration?
It is funny that this has come up a few times now, actually for the third time in a month. I had a question if you can mix AMD and Intel hosts in the same cluster. Although nothing stops you from doing this, and vSAN supports this configuration, you need to remember that you cannot live migrate (vMotion) between those hosts, which means that if you have DRS enabled you are seriously crippling the cluster as it makes balance resource much more complex.
You are creating a Franken cluster when mixing AMD and Intel. You may ask yourself, why would anyone want to do this in the first place? Well, you could do this for migration purposes for instance. If you use vSAN iSCSI Services for instance, this could be a way to migrate those iSCSI LUNs from old hosts to new host. How? Well, simply add the new hosts to the cluster, place the old hosts into maintenance, and make sure to migrate storage. Do note, all the VMs (or containers) will have to be powered off, and powered on again manually on the new hosts, as a result of moving from Intel to AMD (or the other way around).
If you do end up doing this for migration purposes, please ensure it is for the shortest time possible. Please avoid running with a Franken cluster for multiple days, weeks, or, god forbid, months. Nothing good will come out of it, and your VMs may become little monsters!
vSAN Component vote recalculation with Witness Resilience, the follow up!
I wrote about the Witness Resilience feature a few years ago and had a question on this topic today. I did some tests and then realized I already had an article describing how it works, but as I also tested a different scenario I figured I would write a follow up. In this case we are particularly talking about a 2-node configuration, but this would also apply to stretched cluster.
In a stretched cluster, or a 2-node, configuration when a data site goes down (or is placed into maintenance mode) a vote recalculation will automatically be done on each object/component. This is to ensure that if now the witness ends up failing, the objects/VMs will remain accessible. How that works I’ve explained here, and demonstrated for a 2-node cluster here.
But what if the Witness fails first? Well, I can explain it fairly easily, then the VMs will be inaccessible if the Witness goes down. Why is that? Well because the votes will not be recalculated in this scenario. Of course, I tested this and the screenshots below demonstrate it.
This screenshot shows the witness as Absent and both the “data” components have 1 vote. This means that if we fail one of those hosts the component will become inaccessible. Let’s do that next and then check the UI for more details.
As you can see below, the VM is now inaccessible. This is the result of the fact that there’s no longer a quorum, as 2 out of 3 votes are dead.
I hope that explains how this works.
Unexplored Territory #092 – Introducing DSM 2.2 featuring Cormac Hogan!
Recently Data Services Manager 2.2 was released, so it was time for me to ask my friend Cormac Hogan back on the show to share with us what was introduced. Although it was just a “minor” release, there were some major announcements, of which the S3 Object Storage capabilities are probably what will excite you the most! Make sure to listen to the episode either via the player below or on your favorite podcast app. (Spotify, Apple, etc)
Can I have an AF-4 ReadyNode for vSAN ESA with less memory?
I got this question the other day, and it was around the amount of memory the AF-4 ReadyNode configuration needs to have in order for it to be supported. I can understand where the question comes from, but what most people don’t seem to understand is that there’s a set of minimal requirements, and that the ReadyNode profiles are as the KB states a “guidance”. The listed configurations are a guidance. This guidance is based on the anticipated resource consumption for a given set of VMs. Of course, this could be very different for your workload. That is why this article that describes the hardware guidance now clearly states the following:
To maintain a configuration supported by VMware Global Services (GS), all ReadyNodes certified for vSAN ESA must meet or exceed the resources of the smallest configuration (vSAN-ESA-AF-0 for vSAN HCI or vSAN-Max-XS for vSAN Max).
This not only applies to memory, but also to other components, as long as you meet the minimum specified below.
