Migrating to the Cloud – Technical Concerns of migrating to an IaaS Cloud

Blue SquareThe thoughts of migrating to the Cloud can be flippant or daunting depending on where you sit on the optimist/pessimist scale. In reality, this is a matter of proportion to your environment.

In this week’s post, I’m talking specifically about Infrastructure-as-a-Service Cloud — rather than having a physical presence, your goal is to move to the cloud, so you don’t have to care for that hardware stuff.

My recommendation on where to begin is to ask the question: How would I migrate somewhere else?

It starts by – what services do I move 1st? When I worked at UC Irvine‘s School of Humanities in the early 90s, we had to move into a new building and the finance staff needed to move 1st since they didn’t want to get caught with closing the books at the very time we had to evacuate the old modular building. So, a server had to go over there to provide the Netware routing that we were doing between a classroom network and the office network (it was summer, so I didn’t have to worry about student congestion on the network – though the empty classroom I put the server in was victim of the painters unplugging it). After the office staff could move, then I could bring the office Netware server over one evening. The important part of this story is that I needed networking to handle the people 1st.

Another move that I performed was similar. I had to move servers from downtown Denver to a new data center in south Denver. The users of those machines couldn’t deal with the network latency as our route went from downtown Denver to Massachusetts to south Denver. Those users had to move, then they had to get new AD (Microsoft Active Directory) credentials and new security tokens. So, the important part here is that the users needed an authentication infrastructure 1st.

While moving some servers from Denver to Aurora, into a new facility for us – we again were concerned about latency, so we needed to have authentication and name services also stood up in Aurora, so that authentication wouldn’t have to cross the WAN.

My point from these anecdotes is it is not just as simple as moving one OS instance. There are dependencies. Typically, those dependencies are infrastructure dependencies, and they typically exist so that latency can be avoided. [I haven’t defined network latency — but, for those who need an example — think of TV interviews that occur when the anchor is in New York and the reporter is in the middle east. The anchor asks a question and the reporter has to wait for all the audio to get to him while the viewer sees a pause in conversation. That is network latency. The amount of time it takes to travel the “wire”].

Back to dependencies – I may need DNS (domain name service) at the new site, so that every time I look up itbycrayon.com, I don’t have to have the server talk back to my local network to get that information. I may need authentication services (e.g AD). I may need a network route outbound. I may need a database server. Now, these start to add up.

In my experience, there is a 1st wave – infrastructure services.

Then there is a 2nd wave – actual systems used by users. Typically, these are some guinea pigs which can endure the kinks being smoothed out.

Eventually, there are a bunch of systems that are all interrelated. This wave ends up being quite an undertaking, as this bulk of systems takes time to move and users are going to want minimal downtime.

Then after the final user wave, the final clean-up occurs – decommissioning the old infrastructure servers.

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What I’ve presented is more about how to do a migration than a migration into the cloud. For the cloud, there may be additional steps depending on your provider – maybe you have to convert VMware VMs using OVFtool and then import.

VM portability eases the task. The underlying hardware tends to be irrelevant – as opposed to moving physical servers where there may be different driver stacks, different devices, etc. Obviously, one has to be cognizant of compatibility. If one is running IBM AIX, then one must find a cloud provider that supports this.

My point is that it is still a migration of how to get from A to B, and high level requirements remain the same (How is my data going to move – over the wire or by truck? What can I live with? What systems depend on what other systems?). The big difference between an IaaS Cloud migration and a physical migration is that servers aren’t moving from site A to site B – so there isn’t the “swing gear” conversation or the “physical move” conversation. This is a migration of landing on pre-staged gear. The destination is ready. Figure out the transport requirements of your destination cloud and get going!