VMware – vSphere 6 Basics – Platform Services Controller

Posted on 2015-07-24 by dan

I’ve finally gotten some time to dig into the changes in vSphere 6 with regards to deployment options and architecture. I thought I’d do a few posts covering some key enhancements from VMware, paying particular attention to the Platform Service Controller (PSC) and VMware’s preferred deployment options. I haven’t received any briefings from VMware, so I can’t comment on what is coming in future releases. Note that most of this information was made available to me via access to VMware’s partner program, and I think it’s important that more people understand what’s going on when it comes to PSC and how it works.

vSphere Components

The PSC is a new feature in vSphere 6.0. As background, I recommend you first check out this blog post – vCenter Server 6 Deployment Topologies and High Availability. There is also an excellent FAQ from VMware available here. I thought, before diving too much into PSC deployment options, it’s a good idea to revisit VMware’s semi-new approach to vSphere components.

The PSC contains the following services:

VMware vCenter Single Sign-On (SSO);
License Service;
Lookup Service;
VMware Directory Service; and
VMware Certificate Authority (CA).

Everything else is now referred to as “vCenter Services”, providing the remainder of the vCenter Server functionality. This includes:

vCenter Server;
VMware vSphere Web Client;
Inventory Service;
vSphere Auto Deploy;
VMware vSphere ESXi Dump Collector; and
VMware vSphere Syslog Collector (Windows) / VMware Syslog Service (Appliance).

Enhanced Linked Mode and PSC Deployment Options

Here are a few different ways you can do it. Some are good, some are bad. VMware has published a list of recommended topologies for VMware vSphere 6.0.x. The following section provides an overview of the options. Note that some of these options aren’t without their issues.

Enhanced Linked Mode with an External PSC Without HA

The PSC is configured on a separate VM and then the vCenter Servers are joined to that domain, providing Enhanced Linked mode functionality.

Enhanced Linked Mode with an External PSC in an HA Configuration

In this case, the PSCs are configured on separate VMs behind a load balancer to provide HA for the configuration. The vCenter Servers are then joined to that domain using the shared load balancer IP address, providing Enhanced Linked mode functionality that is fault-tolerant.

And here’s a few ways that you can do it that aren’t really recommended.

Enhanced Linked Mode with Embedded PSCs (Not Recommended)

In this scenario, vCenter is installed in an embedded configuration on the first server. Subsequent installations are then configured in embedded mode but joined to an existing SSO domain. Linking the embedded PSCs is possible, but VMware does not recommend this configuration.

Enhanced Linked Mode in Combination Deployment (Not Recommended)

In a combination deployment, the embedded and external PSC architectures are combined. While linking an embedded PSC and an external PSC is possible, VMware does not recommended this configuration.

Enhanced Linked Mode using only an Embedded PSC (Not Recommended)

In this case there is an embedded PSC and vCenter Server linked with an external standalone vCenter Server. Linking a second vCenter Server to an existing embedded vCenter Server and PSC is possible, but VMware does not recommended this configuration.

Sizing Considerations

If you’re not going to use enhanced linked mode, use an embedded PSC. You still have availability via VMware HA. The failure domain is limited to a single vCenter Server, as there is no dependency on external component connectivity for PSC connectivity. This is most suitable for lab environments.

For sites that will use enhanced linked mode use external PSCs. The number of controllers depends on the size of the environment:

Between 2 and 4 VMware solutions – a single PSC for no HA, and 2 will be required for HA configured behind a single load balancer.
Between 4 and 8 VMware solutions – two PSCs linked together for no HA, and four will be required for HA configured behind two load balancers (two behind each load balancer).
Between 8 and 10 VMware solutions – three PSCs linked together for no HA, and six will be required for HA configured behind three load balancers (two behind each load balancer).

HA is provided by having multiple PSCs and a load balancer to provide failure protection. All components are still protected by VMware HA. This VMware KB has more information on how to set this up – Configuring PSC 6.0 High Availability for vSphere 6.0 using vCenter Server 6.0 Appliance.

vCenter Platform Choice

VMware maintain that, with the improvements to the vCenter appliance platform, the choice of Windows-based vs vCenter appliance is now a matter of preference rather than performance. I recommend the appliance wherever possible, but some people will feel more comfortable with a Windows-based platform. The cool thing is that, if you want to make things complicated, the PSC supports mixed-mode (i.e. appliance and Windows-based vCenter deployments).

Final Thoughts

This may have gone a bit beyond basics, and it’s not something that’s necessarily going to come up each day. But if you’re working either directly with VMware, via an integrator or doing it yourself, this new approach should be a key consideration in your planning activities. The addition of the PSC concept to the vCenter architecture improves the flexibility and availability options of the product, something that I think VMware has struggled with in the past. The key takeaway, in my opinion, is that if you’re upgrading from 5.5 or below, you need to take the time to plan appropriately, particularly if you want to leverage some of the new features that are available.

VMware – SRM 5.8 – You had one job!

Posted on 2015-06-10 by dan

The Problem

A colleague of mine has been doing some data centre failover testing for a customer recently and ran into an issue with VMware’s Site Recovery Manager (SRM) 5.8 running on vSphere 5.5 U2. When attempting to perform a recovery, and you’re running Linked Mode, and the protected site is off-line, the recovery may fail. The upshot of this is “The user is unable to perform a recovery at the recovery site, in the event of a DR scenario”. Here’s what it looks like.

The Reason and Resolution

You can read more about the problem in this VMware KB article: Performing a Recovery using the Web Client in VMware vCenter Site Recovery Manager 5.8 reports the error: Failed to connect Site Recovery Manager Server(s). In short, there’s a PowerShell script you can run to make the recovery happen.

Conclusion

I don’t know what to say about this. I’d like to put the boot into whomever at VMware is responsible for this SNAFU, but I’m guessing that they’ve already had a hard time of it. At least, I guess, there’s a workaround, if not a fix. But you’d be a bit upset if this happened for the first time during a real failover. But that’s why we test before we handover. And what is it with everything going pear-shaped when Linked Mode is in use?

*Update – 29/10/2015*

Marcel van den Berg recently pointed out that updating to SRM 5.8.1 resolves this issue. Further detail can be found here.

EMC – VSI for VMware vSphere 6.5 Linked Mode Issue – Redux

Posted on 2015-05-21 by dan

I wrote in a previous post about having some problems with EMC’s VSI for VMware vSphere 6.5 when running in vCenter 5.5 in Linked Mode. I spoke about deploying the appliance in just one site as a workaround. Turns out that wasn’t much of a workaround. Because workaround implies that I was able to get some functionality out of the situation. While the appliance deployed okay, I couldn’t get it to recognise the deployed volumes as EMC volumes.

A colleague of mine had the same problem as me and a little more patience and logged a call with EMC support. Their response was “[c]urrent VSI version does not support for Linked mode, good news is recently we have several customers requesting that enhancement and Dev team are in the process of evaluating impact to their future delivery schedule. So, the linked mode may will be supported in the future. Thanks.”

While this strikes me as non-optimal, I am hopeful, but not optimistic, that it will be fixed in a later version. My concern is that Linked Mode isn’t the problem at all, and it’s something else stupid that I’m doing. But I’m short of places I can test this at the moment. If I come across a site where we’re not using Linked Mode, I’ll be sure to fire up the appliance and run it through its paces, but for now it’s back in the box.

EMC – VSI for VMware vSphere 6.5 Linked Mode Issue

Posted on 2015-05-05 by dan

As part of a recent deployment I’ve been implementing EMC VSI for VMware vSphere Web Client v6.5 in a vSphere 5.5 environment. If you’re not familiar with this product, it “enables administrators to view, manage, and optimize storage for VMware ESX/ESXi servers and hosts and then map that storage to the hosts.” It covers a bunch of EMC products, and can be really useful in understanding where your VMs sit in relation to your EMC storage environment. It also really helps non-storage admins get going quickly in an EMC environment.

To get up and running, you:

Download the appliance from EMC;
Deploy the appliance into your environment;
Register the plug-in with vCenter by going to https://ApplianceIP:8443/vsi_usm/admin;
Register the Solutions Integration Service in the vCenter Web Client; and
Start adding arrays as required.

So this is all pretty straightforward. BTW the default username is admin, and the default password is ChangeMe. You’ll be prompted to change the password the first time you log in to the appliance.

So the problem for me arose when I went to register a second SIS appliance.

By way of background, there are two vCenter 5.5 U2 instances running at two different data centres. I do, however, have them running in Linked Mode. And I think this is the problem. I know that you can only register one instance at a time with one vCenter. While it’s not an issue to deploy a second appliance at the second DC, every time I go to register the service in vCenter, regardless of where I’m logged in, it always points to the first vCenter instance. Which is a bit of a PITA, and not something I’d expected to be a problem. As a workaround, I’ve deployed one instance of the appliance at the primary DC and added both arrays to it to get the client up and running. And yes, I agree, if I have a site down I’m probably not going to be super focused on storage provisioning activities at my secondary DC. But I do enjoy whinging about things when they don’t work the way I expected them in the first instance.

I’d read in previous versions that Linked Mode wasn’t supported, but figured this was no longer an issue as it’s not mentioned in the 6.5 Product Guide. This thread on ECN seems to back up what I suspect. I’d be keen to hear if other people have run into this issue.