Tag Archives: vCloud Air

vCloud Air OnDemand and DR Overview

Recently, I worked on a project to deploy for a customer vCloud Air Disaster Recovery.  Along the way, as mentioned in a previous post, I went ahead and picked up the applicable VMware certification for it.  I wanted to discuss how vCloud Air works.  To begin with, I wanted to discuss the two offerings, and how they interact.

vCloud Air OnDemand

vCloud Air OnDemand is a public cloud Infrastructure As a Service (IAaS) solution.  You can run pretty much whatever workloads you like.  These are VMs or appliances you deploy either manually by yourself, using their catalog, or perhaps even upload templates from your VMware on premise  environment.

vCloud Air Disaster Recovery

vCloud Air Disaster Recovery is a public cloud Infrastructure As a Service solution.  It’s identical to vCloud Air OnDemand except it’s geared specifically for failing over replicated virtual machines.  VMs you run in this cloud can only be replicated virtual machines from your vSphere environment.  These VMs are replicated with vSphere Replication.  In addition, you can designate isolated networks within vCloud Air DR for isolated testing.

Two Separate Clouds

One design concept to understand is vCloud Air OnDemand and vCloud Air Disaster Recovery are two completely separate clouds.  While they have very similar features and management interfaces, they are completely independent and separate.  This is so much so that in order for VMs in either to be able to communicate with each other, you must setup site to site VPN connections between them.  Keep this in mind.

When Should I Use vCloud Air OnDemand vs Disaster Recovery?

This seems obvious, right?  If you want to replicate VMs using a whole VM replication technology and fail VMs over, use DR.  Use OnDemand when application or service data will replicate natively instead of whole VM replication.

But it’s not so simple as that.  What if a VM has the ability to replicate within its service or application?  Do some services and replication prohibit you from using whole VM replication?

The giant elephant in the room for DR solutions when asking these questions is Active Directory.  If you want your DR solution to be wholly independent, you likely need domain controllers in the cloud and on premise.  And it’s not supported to use whole VM replication with Active Directory Domain Controllers.  So, DCs are out for use with vCloud Air DR for production use cases.

Generally speaking, it maybe a bad idea for infrastructure bread and butter type VMs generally speaking.  For example, DHCP servers could be replicated, but the problem is vSphere Replication can only configure VMs with as low a RPO as 15 minutes, and going over a WAN link might make that 15 minute RPO at best impossible with all your other VMs you’re replicating.  Perhaps it would be better to build a VM within OnDemand and run a script to export the DHCP database regularly to the DR site.

Bottom line though is this:  You only need OnDemand if you won’t replicate VMs using vSphere Replication to vCloud Air.  If you want to run replicated VMs within vCloud Air as a DR solution, AND you want to ensure that the vCloud DR site is not dependent at all on your on premise infrastructure, you probably need both if only to facilitate running Domain Controllers.  Perhaps other services and applications you’ll replicate data to through other means, too.

It would look something like this:



VCA6-HC exam review

I’ve been doing some work with vCloud Air, which got me really reading up on everything, and taking advantage of learning resources available.  It occurred to me that maybe there’s a cert for this, so I looked into it, and there is – VMware Certified Associate 6 – Hybrid Cloud (VCA6-HC).

I’ve not taken any VMware Certified Associate exams because I was a VCAP by the time this certification level became available from VMware, and I’ve stayed within the Data Center Virtualization track.  But in this case, I had no plans to jump higher in the Cloud Management and Automation track in the foreseeable future, and it would be nice to validate skills and knowledge I’d acquired over the past week of work and my weekend learning, and I scored an 88% on the practice exam, so why not?

VCA exams, if you’re not familiar with them, are paid exams you take on your computer, and are effectively “open book”.  I didn’t prepare for this VCA6-HC exam exhaustively like I normally do, but I did go through the exam topics, ensured I felt comfortable with the topics, and I had already read through most of the documents they suggested specifically to read (the vCloud Air Users Guide and the vCloud Air Networking Guide), but there were a few more that were more marketing type stuff, so I glanced through those.  I also did some stuff on VMware’s Partner Portal for VTSP for Hybrid Cloud, too, which I think covered me on the marketing side.

The VCA6-HC exam is 50 questions, and you have 75 minutes to complete it.  The exam interface is pretty much exactly like a VCP exam.  There are multiple choice, select X out of the following option type questions.  You can mark questions to go back to for review in case you don’t want to waste time on it right then.  I had absolutely no problem finishing the exam within 75 minutes.  I completed the exam first pass within about 30 minutes, reviewed the ones I marked and then reviewed all of my answers one more time within about 45 minutes, and went ahead and ended it.  You need to score at least 300, and I received a 400.

How difficult is VCA6-HC?  It’s not a tough exam, especially with it being open book.  A few tips I’d offer would be:

  • Be very familiar with the networking basic concepts.  You’ll likely fail if you don’t.
  • Know the different services and basic options offered for vCloud Air.
  • Know the basic functionality and architecture of all the management tools related to vCloud Air the video training covers.
  • Do the free video training they have.  Pretty good chance you’ll fail if you don’t.

All and all, it’s a pretty straight forward exam.  I’m not wild about VMware/Pearson charging $120 for this exam.  I just think that’s an awful lot to charge people for a basic exam like this that’s proctored online.  IMO, these exams probably should be free, or dirt cheap.

But, at least there’s a certification out there to vet familiarization with vCloud Air, so it’s back to VCAP6-DCV Deployment, which I REALLY need to get cracking on!