Yellow Bricks

by Duncan Epping

BC-DR

HA Admission control: How can I check how much reserved resources are used?

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I had this question twice in the past three months, so somehow this is something which isn’t clear to everyone. With HA Admission Control you set aside capacity for fail-over scenarios, this is capacity which is reserved. But of course VMs also use reservations, how can you see what the total combined used reserved capacity is including Admission Control?

Well, that is actually pretty simple it appears. If you open the Web Client, or the H5 client, and go to your cluster then you have a “Monitor” tab, under the Monitor tab there’s an option called “Resource Reservation” and it has graphs for both CPU as well as Memory. This actually includes admission control. To verify this I took a screenshot in the H5 client before enabling admission control, and after enabling it, as you can see a big increase in “reserved resources”, which indicates that admission control is taken into consideration.

Before:

After:

This is also covered in our Deep Dive book, by the way, if you want to know more, pick it up.

HCI3041BU: Introducing Scalable File Storage on vSAN

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Another beta announcement last week for vSAN was around Native File Services. This was the topic of HCI3041BU, which was titled “Introducing Scalable File Storage on vSAN with Native File Services”. The full session can be found here, the summary is below for your convenience. The session was by Venkat Kolli (Product Manager) and engineers Rick Spillane and Wenguang Wang.

Venkat kicks of the session describing the different types of storage most of our customers have in their data center today, and also what kind of data lands on the different types of storage. Basically, it is divided into three main types: Block, File, and Object. Where I personally believe that “object” is at the point of becoming more common on-premises but for many is consumed as a cloud service. Looking at where the data growth is today, it is mainly in the “unstructured data” space.

Next Venkat discusses the management complexity of traditional file storage, not just management complexity but also scaling and forecasting. Which in most cases leads to increased cost. How can vSAN help with simplifying File Services and lowering cost by providing a framework which allows you to serve block, file and object. For now, we are discussing file-services however, but the vision is clear.

Rick is up next introducing File Services. vSAN File Services allows you to create file shares and provide file services to users/consumers through the same familiar interface you have available today in vSphere. On top of that, you get to leverage the power of policy-based management to provision file shares in a specific way. Which means that File Shares will work in stretched clusters, can be protected with vSAN Data Protection, can be striped/replicated etc. Most important piece of feedback during the design phase from customers was that they did not want a separate storage cluster to manage for file services, this needed to be an integral part of today’s offering.

The requirements and design principles for the vSAN Distributed File System were:

  • Elastic Scaling
    • Scale IOPs up/down
  • Single namespace across the cluster
  • Centrally managed, configured and monitored
  • Transparent failover
  • POSIX File Interface
  • Use vSAN services like data path, consensus mechanisms, and checksumming

Rick next explains a new platform that will (potentially) be included in vSAN, this is called the Storage Services Platform. What this provides is stateless containerized frontend servers which sit on top of the vSAN Distributed File System. This will be available for both VMware and partners, so even partners should be able to provide storage services through this platform. Data will sit in the VDFS volumes and then will be exposed through these services. These services, of course, are fully distributed and self-managing.

The Storage Services Platform is implemented in the form of a storage services control plane. This control plane will for instance monitor all front-end servers and node and help in the case of failures, but also will help to ensure availability during maintenance and upgrade. Also, when it comes to scalability the control plane monitors the instances and allows to scale up and down when needed.

Okay, that sounds great, but how do file shares get formed? File shares will be an aggregate of one or multiple vSAN Objects. The great thing about this is that it allows for elasticity in size and performance, plus policies can be associated with these objects. You can now simply create file shares through the UI, or leverage the API. The vSAN team made sure that you can access it and define them the way you prefer. On top of that, this platform will also be available to Kubernetes as part of our Cloud Native Storage Control Plane.

Next Rick briefly discussed data protection for file shares, he mentioned that the team has worked with various 3rd party vendors to allow for full backup and recovery, including file-level restore. What Rick also revealed, surprisingly enough, is that in the initial release we will have:

  • NFS v4.1 support
  • AD-based Authentication
  • Kerberos
  • Containerized application support

And in the release after that support for the following is planned:

  • SMB
  • vSAN DP Integration
  • OpenLDAP support

Next Wenguang came up on stage, and he demoed vSAN File Services. He showed how simple it is to enable File Services in the UI. Literally, a couple of steps, provide the networking details and also authentication mechanism. The next step will be to download an OVF, this contains the frontend service we spoke about earlier, for now, this is an NFS server, but this could be other services in the future. After the File Services have been enabled and the OVF is deployed you can start creating file shares. Again this is very straightforward, part of the familiar vSAN UI / HTML-5 interface, which is what I like most, if you know vSAN and/or vSphere you will be able to use vSAN File Services as well. I hope potential other services will be implemented in a similar easy manner.

The Q&A was interesting as well, as some questions around the potential SMB implementation were answered (SAMBA on Linux vs Microsoft vs Dell/EMC stack?) and for instance what block size is used for the file system (4K, like vSAN).

All in all a very exciting solution, and a great overview of what you can expect in the future for vSAN. Note that this is part of the beta, so if you are interested sign up!

HCI1603BU – Tech Preview of Native vSAN Data Protection

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The second session I watched was HCI1603BU Tech Preview of Native vSAN Data Protection by Michael Ng. I already discussed vSAN Data Protection last year, but considering the vSAN Beta is coming up soon that includes this functionality I felt it was worth covering again. Note that the beta will be a private beta, so if you are interested please sign up, you may be one of the customers getting selected for the beta.

Michael started out with an explanation about what an SSDC brings to customers, and how a digital foundation is crucial for any organization that wants to be competitive in the market. vSAN, of course, is a big part of the digital foundation, and for almost every customer data protection and data recovery is crucial. Michael went over the various vSAN use cases and also the availability and recoverability mechanisms before introducing Native vSAN Data Protection.

Now it is time for the vSAN Native Data Protection introduction. Michael first explains that we will potentially have a solution in the future where we can simply create snapshots locally through specifying the number of local snapshots you want in policy. On top of that, in the future, we will potentially provide the option to specify the snapshots (plus a full copy) will need to be offloaded to secondary storage. Secondary storage could be NFS, S3 Object Storage (both on-premises and in the cloud). Also, it should be possible to replicate VMs and snapshots to a DR location through policies.

What I think is very compelling is the fact that the native protection comes as part of vSAN/vSphere, there’s no need to install an appliance or additional software. vSAN Data Protection will be baked into the platform. Easy to enable and easy to consume through policy. The first focus is vSAN Local Data Protection.

vSAN Local Data Protection will provide Crash and Application-consistent snapshots at an RPO of 5 minutes and with a low RTO. On top of that, it will be possible to instant clone the snapshot. Meaning that you can restore the snapshot as an “instant clone”, this could be interesting when you want to test a certain patch or upgrade for instance. You can even specify during the recovery that the NIC doesn’t need to be connected. Application consistency is achieved by leveraging VSS providers on Windows and on Linux the VMware Tools pre- and post-scripts are being used.

What enables vSAN Data Protection is a new snapshotting technology. This new technology provides a lot better performance than traditional vSphere (or vSAN) snapshots. It also provides for better scale, meaning that you can go way above the 32 limit we currently have.

Next Michael demoed vSAN Data Protection, which is something I have done on various occasions if you are interested in what it looks like just watch the session. If I have time I may record a demo myself just so it is easier to share with you.

What I personally hadn’t seen yet were the additional performance views added. Very useful as it allows you to quickly check what the impact is of snapshots on general performance. Is there an impact? Do I need to change my policy?

Last but not least various questions were asked, most interesting parts was the following:

  • “file level restore” is on the roadmap but the first feature they will tackle is offloading to secondary storage.
  • “consistency groups” is something that is being planned for, especially useful when you have applications or services spanning VMs.
  • Integration with vRealize Automation, some of it is planned for the first release, everything is SPBM based which already have APIs. Being planned for is “self-service restore”
  • 100 snapshots per VM is tested for the first release

Good session, worth watching!

VMworld Video: vSphere 6.7 Clustering Deep Dive

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As all videos are posted for VMworld (and nicely listed by William), I figured I would share the session Frank Denneman and I presented. It ended up in the Top 10 Sessions on Monday, which is always a great honor. We had a lot of positive feedback and comments, thanks for that! Most importantly, it was a lot of fun again to be up on stage at VMworld talking about this content after 6 years of absence or so. For those who missed it, watch it here:

Also very much enjoyed the book signing session at the Rubrik booth with Niels and Frank. I believe Rubrik gave away around 1000 copies of the book. Hoping we can repeat this huge success in EMEA. But more on that later. If you haven’t picked up the book yet and won’t be at VMworld Europe, consider picking it up through Amazon, e-book is 14.95 USD only.


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.