VCSA: Deployed with no external DNS?

External DNS is a documented requirement for vCenter in a supported deployment model [read the documentation.] However, are there are times when you want to set up vCenter without any DNS?
When on earth would you want that?

  • Small lab or POC
  • Tiny Environments for an initial standup prior to providing DNS
  • DR scenarios when services (including DNS) are down you may need to manage multiple hosts and simply get recovery VM’s running (this can be avoided through good design, but it can happen.)
  • Home Labs, of course

When do you NOT want vCenter without DNS?

  • Anytime you need to count on VCSA long-term. Just don’t.
  • Any deployment of vCSA with an external PSC or any of the extended features like Linked Mode/Enhanced Linked Mode, Stretched Clusters, etc.
  • Also, don’t expect to get LDAP integration working.

So you still want to deploy vCSA and don’t want to depend on DNS forward/reverse lookups? Read on… it’s pretty easy.

The Key Thing…

The bottom line here is that there are a few configuration points you have to diverge from. It’s simplest to explain this from the scripted installer configuration because these variables are clearly laid out. (William Lam writes up the whole process over at Virtually Ghetto. )

It’s also a good bit easier to deploy with the scripted installer if your skills permit it. Again, see William Lam’s posts for a primer.

The JSON looks like this and we’re after the network settings.

If you read carefully you will notice a few things that are unusual.

  • The DNS server (only one) is the same as the system IP
  • The System Name is also using this same address

Both these are deliberate and required for a no-external-DNS VCSA.

What’s happening here? This is declaring that VCSA is going to be it’s own DNS server, and that seems to work just fine.

UI Installer

Stage 1 of the installer is straightforward. In my screenshots I’m deploying an embedded PSC model and the only critical piece that’s unusual here is to keep the System Name, IP address, and DNS Servers all at the same address you’re deploying vCSA to.

 

 

 

 

 

Once you’ve deployed stage 1, Stage 2 is straightforward, but Stage 2 WILL NOT proceed without a functioning network. So if you blew it in Stage 1, you’ll know it right at the start of Stage 2.

In this example I’ve deployed VCSA 6.7, the lastest-greatest at the time of writing. However, I’ve done this with success all the way back to VCSA 6.0.

Recap

Don’t deploy a no-dns VCSA if you expect it to scale or you want to grow the environment.

Don’t deploy a no-dns VCSA if you expect it to be supported. VMware will point you to the documentation and likely leave you alone with your problems.

But do you want to stand up a VCSA for a nested ESXi or other lab use with minimal effort? Give this a spin and reach out on twitter if you have trouble–I’d be interested to hear.

 

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