In vSphere 5.5, the SSO (Single-Sign On) component has been completely re-designed to help simplify the management of your SSO Server(s). A built-in automatic multi-master replication architecture is now used to ensure that all SSO instances are always kept in synced. This works great for a pure Windows based environment but what if you wanted to run a hybrid environment that includes a mix of vCenter Server on Windows and the VCSA (vCenter Server Appliance)?
A great use case for this would be for ROBO site management for which you want to simplify the deployment and management of these sites from a centralized location. Instead of deploying additional vCenter Servers on Windows and spend more on Windows licenses, you could leverage the VCSA. With this hybrid model you can still gain all the benefits of having a distributed SSO security domain as well as a centralized place for managing and accessing all your vCenter Servers and Virtual Machines. As you can see from the diagram below, the SSO replication is bi-directional from all SSO instances and this occurs by default every 30seconds. By joining all SSO instances under a common SSO security domain (vsphere.local), you also have the added benefit of being able to see inventory from all SSO instances by logging into anyone of the vSphere Web Clients at each site.
I was recently asked by a couple of VMware colleagues about this particular configuration and whether it would be possible with using the VCSA. It took a couple of days of tinkering in the lab, talking to some folks and several dozen snapshot reverts, but I am please to say I have been successful in getting this to work!
Disclaimer: This configuration is not officially supported by VMware as the configuration has not been officially been tested. Please use at your own risk.
- Configured Windows vCenter Server
- Un-configured VCSA deployed
Step 1 - Deploy vCenter Server 5.5 on a Windows server as you normally would.
Step 2 - Deploy a VCSA but do not configure it just yet, we have a script that will automate this for you.
Step 3 - Download configureAdditionalVCSAUsingCommonSSODomain.sh script which will automatically configure the VCSA to point to the external vCenter Server SSO instance as well as setup the SSO multi-master replication configuration. You can either run the script remotely or run it within the VCSA, but before you do you will need to edit the script and modify the following variables.
The first three variables pertains to your Windows vCenter Server and make sure the username is email@example.com The SSO Site name can be identified by following the instructions found here. In addition to the above mandatory variables, there are a couple other variables that will automatically join the VCSA to an Windows Active Directory, you just need to enable the flag and fill in the variables.
Step 4 - You are now ready to run the script! The output is a bit verbose, but if you take a look at the script itself is is only a couple of lines 🙂 This is wayyy easier than deploying a Windows OS and then go through all those complex install wizards!
The majority of the script is actually from an earlier script that I wrote during vSphere 5.1 release for the VCSA. However, there are a couple of additions to the script that I would like to highlight. The first is starting all the VMware SSO Services and also ensure it is automatically started up during boot by running the following commands:
/sbin/chkconfig vmdird on
/sbin/chkconfig vmware-sts-idmd on
/sbin/chkconfig vmkdcd on
/sbin/chkconfig vmcad on
The final part is to configure the replication between the two vmdird instances using the /usr/lib/vmware-vmdir/bin/vdcpromo command. The command requires both the source and target username/password of the SSO administrator account as well as the source SSO Site name which can be identified by following the instructions here.
Once the script has finished (should only take a minute or two) you now can login to either vCenter Server instances and you will be able to see both your vCenter Server on Windows as well as your VCSA.
Note: Currently, the Lookup Service is shared between all vCenter Servers joined to the common SSO security domain. This behavior is not expected and is currently being investigated by engineering. In the meantime, if the primary vCenter Server hosting the Lookup Service is unavailable, you will not be able to login to your other vCenter Servers. You should ensure proper high availability solutions is provided for the vCenter Server hosting the Lookup Service until this issue is resolved.
In just under a couple of minutes you can easily deploy several VCSA's joined to a common SSO security domain with built-in replication and get a "poor" mans Linked Mode to view and manage all your vCenter Servers from a single place.
Note: Even though SSO multi-master replication between VCSA's is not officially supported by VMware, it does in fact work and is something I have been able to setup in my lab. To perform this, you just need to setup you first VCSA as you normally would and using the script above to join additional VCSA to the first one you setup.
In a follow-up blog post, I will show you how to verify SSO multi-master replication is properly configured and replicating using some free online tools.