Yellow Bricks

by Duncan Epping

VMware

UI Confusion: VM Dependency Restart Condition Timeout

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Various people have asked me, and I wrote about this before in several articles but as part of a longer article which makes it difficult to find. When specifying the restart priority or restart dependency you can specify when the next batch of VMs should be powered on. Is that when the VMs are powered on when they are scheduled for being powered on, when VMware Tools reports them as running or when the application heartbeat reports itself?

In most cases, customers appear to go for either “powered on” or “VMware Tools” heartbeat. But what happens when one of the VMs in the batch is not successfully restarted? Well HA waits… For how long? Well that depends:

In the UI you can specify how long HA needs to wait by using the option called “VM Dependency Restart Condition Timeout”. This is the time-out in seconds used when one (or multiple VMs) can’t be restarted. So we initiate the restart of the group, and we will start the next batch when the first is successfully restart or when the time-out has been exceeded. By default, the time-out is 600 seconds, and you can override this in the UI.

What is confusing about this setting is the name, it states “VM Dependency Restart Condition Timeout”. So does this time-out apply to “Restarts Priority” or does it apply to “Restart Dependency” or maybe both? The answer is simple, this only applies to “Restart Priority”. Restart Dependency is a rule, a hard rule, a must rule, which means there’s no time-out. We wait until all VMs are restarted when you use restart dependency. Yes, the UI is confusing as the option mentions “dependency” where it should really talk about “priority”. I have reported this to engineering and PM, and hopefully it will be fixed in one of the upcoming releases.

VMworld – VMware vSAN Announcements: vSAN 6.7 U1 and beta announced!

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VMworld is the time for announcements, and of course for vSAN that is no different. This year we have 3 major announcements and they are the following:

  • VMware vSAN 6.7 U1
  • VMware vSAN Beta
  • VMware Cloud on AWS new features

So let’s look at each of these, first of all, VMware vSAN 6.7 U1. We are adding a bunch of new features, which I am sure you will appreciate. The first one is various VUM Updates, of which I feel the inclusion of Firmware Updates through VUM is the most significant one. For now, this is for the Dell HBA330 only, but soon other controllers will follow. On top of that there now also is support for custom ISO’s. VUM will recognize the vendor type and validate compliance and update accordingly when/if needed.

The other big thing we are adding os the “Cluster Quickstart wizard“. I have shown this at various sessions already, so some of you may be familiar with it. It basically is a single wizard that allows you to select the required services, add the hosts and configure the cluster. This includes the configuration of HA, DRS, vSAN and the network components needed to leverage these services. I recorded a quick demo that actually shows you what this looks like

One of the major features in my opinion that is introduced is UNMAP. Yes, unmap for vSAN. So as of 6.7 U1 we are now capable of unmapping blocks when the Guest OS sends an unmap/trim command. This is great as it will greatly enhance/improve space efficiency. Especially in environments where for instance large files or many files are deleted. You need to enable it, for now, through “rvc”. And you can do this as follows:

/localhost/VSAN-DC/computers/6.7 u1> vsan.unmap_support -e .

When you run the above command you should see the below response.

Unmap support is already disabled
6.7 u1: success
VMs need to be power cycled to apply the unmap setting
/localhost/VSAN-DC/computers/6.7 u1>

Pretty simple right? Does it really require the VM to be power cycled? Yes, it does, as during the power-on the Guest OS actually queries for the unmap capability, there’s no way for VMware to force that query without power cycling the VM unfortunately. So power it off, and power it on if you want to take advantage of unmap immediately.

There are a couple smaller enhancements that I wanted to sum up for those who have been waiting for it:

  • UI Option to change the “Object Repair Timer” value cluster-wide. This is the option which determines when vSAN starts repairing an object which has an absent component.
  • Mixed MTU support for vSAN Stretched Clusters (different MTU for Witness traffic then vSAN traffic)
  • Historical capacity reporting
  • VROps dashboards with vSAN stretched cluster awareness
  • Additional PowerCLI cmdlets
  • Enhanced support experience (Network diagnostic mode, specialized dashboards), you can find the below graphs under Monitor/vSAN/Support
  • Additional health checks (storage controllers firmware, unicast network performance test etc)

And last but not least, with vSAN Stretched we have the capability to protect data within a site. As of vSAN 6.7 U1 we also now have the ability to protect data within racks, it is however only available through an RPQ request. So if you need protection within a rack, contact GSS and file an RPQ.

Another announcement was around a vSAN Beta which is coming up. This vSAN Beta will have some great features, three though have been revealed:

  • Data Protection (Snapshot based)
  • File Services
  • Persistent Storage for Containers

I am not going to reveal anything about this, simply to avoid violating the NDA around this. Sign up for the Beta so you can find out more.

And then the last set of announcements was around functionality introduced for vSAN in VMware Cloud on AWS. Here there were two major announcements if you ask me. The first one is the ability to use Elastic Block Storage (EBS volumes) for vSAN. Meaning that in VMware Cloud on AWS you are no longer limited to the storage capacity physically available in the server, no you can now extend your cluster with capacity delivered through EBS. The second one is the availability of vSAN Encryption in VMware Cloud on AWS. This, from a security perspective, will be welcomed by many customers.

That was it, well… almost. This whole week many sessions will reveal various new potential features and futures. I aim to report on those when sitting in on those presentations, or potentially after VMworld.

 

What happens if all hosts in a vSphere HA cluster are isolated?

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I received this question through twitter today from Markus who was going through the vSphere 6.7 Clustering Deep Dive. And it is fairly straightforward: what happens when all hosts are isolated in a cluster, will the isolation response be triggered?

https://twitter.com/RealRockaut/status/1029652167735631874

I wrote about this a long long time ago, but it doesn’t hurt to re-iterate this. Before triggering the isolation response HA will actually verify the state of the rest of the cluster. Does anyone own the datastore on which the VMs that are impacted by this isolation run? If the answer is no, the ownership of a datastore is dropped during the election, then HA will not trigger the isolation response. I will try to update the book when I have time to include that, hopefully, that means a new version of the ebook will be pushed out to all owners automatically.

You asked for it: vSphere 6.7 Clustering Deep Dive ebook, now available!

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We knew when we released the paper version of the book that many would yell: What about an e-book? Although sales numbers of the Host Deep Dive and previous Clustering Deep Dive books have shown that by far most people prefer a printed copy, we decided to go ahead and create an ebook as well. It is not as simple unfortunately as simply uploading a PDF or an MS Word file. We had to spend evenings reformatting the book in an e-book authoring tool, compile it, review it, fix issues, compile again etc. Nevertheless, it is done!

So what we did is we just uploaded it to Amazon, and we made it available for 14,95 USD, or whatever that roughly converts to in your local currency in your local store. We also noticed there was a bundling option, so as soon as the ebook and the paper copy are linked you can buy the ebook alongside the paper copy for only 2,99 USD. (Linking the book may still take a couple of days, we’ve initiated the process with Amazon and are waiting for them to complete it.)

You wanted it, so go out and pick it up, right before the weekend! Also, note that we have both the ebook and the paper version available right now, we are working on linking the books, so you can get a nice deal for both versions. Also, I would highly recommend picking up the Host Deep Dive books as well, and while you are at it pick up the VDI guide, it is an excellent read! Amazon links are on the right side for your convenience.

Now Available: vSphere 6.7 Clustering Deep Dive book!

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Over the past couple of months Frank, Niels and I have worked ferociously to update the vSphere Clustering Deep Dive. Some of the material was already brought up to date to vSphere 6.0 U2, but the majority was never updated after vSphere 5.1. As you can imagine, this was a tremendous undertaking. Not only did we need to validate every sentence, all diagrams needed to be updated, and with the introduction of the HTML-5 Client also all screenshots had to be retaken. 

Now, just a couple of weeks before VMworld, we are finally at the point where we can press “publish”.

What can you expect? Well, we have said this with previous books, this is not a beginners guide! This is a deep dive, and we aimed to take you in to the trenches of vSphere Clustering technologies. We cover a multitude of different features, and for those who haven’t read the previous books expect the following features to be covered:

  • vSphere HA
  • vSphere DRS
  • vSphere Storage DRS
  • vSphere Storage I/O Control
  • vSphere Network I/O Control

We also have a chapter on stretched clusters, in this chapter we describe how to design and implement a vSphere Metro Storage Cluster, leveraging all of the knowledge gained in the previous chapters.

For your convenience, I copied/pasted some of the Amazon info below.

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  • Paperback: 566 pages
  • Publisher: CreateSpace Independent Publishing Platform; 1 edition (July 29, 2018)
  • Language: English
  • ISBN-10: 1722625325
  • ISBN-13: 978-1722625320
  • Product Dimensions: 5.5 x 1.3 x 8.5 inches
  • Shipping Weight: 1.8 pounds

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I hope all of you will enjoy the book as much as we enjoyed writing it. And before I forget, I want to thank my co-authors for the late night discussions, the hard work, insights and fun/laughter at times.

Get it while it is hot! (Look on the right side column for the links to the book!)