Cloud migration tools can alleviate some of the burden of moving workloads from private to public clouds, but once applications are in a public cloud, beware: It may take a manual process to switch to another provider.
There is no silver bullet yet for performing fully automated soup-to-nuts cloud-to-cloud migrations, which includes the required IP address and domain name system (DNS) changes, as well as application testing, experts say.
IT pros may have to change DNS from pointing to a network address translation to pointing to individual machines, for example, according to Edward Haletky, CEO of The Virtualization Practice LLC, based in Austin. Testing that an application works correctly in a new data center is a process that often takes longer than the migration itself.
"Most testing today is an extremely manual process," Haletky said.
Most testing today is an extremely manual process.
CEO, The Virtualization Practice LLC
IT pros say that the core of the process -- movement of virtual machines along with their associated configurations, operating systems, applications and storage from one cloud computing provider to another -- can take manual intervention, as well.
After some outages and performance issues with Amazon Web Services (AWS), Ray Williamson, CTO of Best Fit Mobile, a mobile app development company based in Austin, was charged with moving an application built for the Michael's chain of arts and crafts stores to Rackspace's public cloud.
"We spent about a week and a half getting all the machines and the data lined up," he said. "We synchronized both clouds so that everything was ready to go."
This required assistance from Rackspace as the appropriate number of machines was spun up and tested, along with an approximately 800 GB import of data.
Both clouds are still kept in sync so that AWS can remain a backup in case of an outage at Rackspace. This requires weekly migrations of SQL files between the two services, which are also done manually.
"Often you end up using an Amazon or a Rackspace as an intermediary during migrations, just because it's easier to stick your big bulk of data in some cloud storage while you get the new environment set up," said Jon Wyrick, CEO of Beyond Secure, a cloud consultancy based in Austin and a veteran of numerous client migrations between clouds.
Ideally, Wyrick would like to see dark fiber connections between providers to make migrations easier, but doesn't expect this to happen between competitors.
"A lot of the large customers we have end up building distributed infrastructures where they don't have to depend on any one vendor," he said. "But small- and mid-tier customers just can't afford that sort of thing."
PaaS migration between clouds even trickier
The bulk of IaaS migration is transferring between data storage repositories, but applications are more deeply tied in to the individual platform in PaaS.
"PaaS players support same language sets, but do so in different ways, so there's always a bit of application rewriting that has to occur even if you're going between vendors who support the same language," said David Linthicum, CTO and founder of Blue Mountain Labs, a cloud advisory firm based in St. Louis, Mo.
"You use a certain set of APIs to do things like scale, set up new instances, and do things like caching, said John Grange, managing director for Layered Innovations, Inc., an Omaha, Neb.-based firm that makes marketing automation software.
"When you get deep into those application-level services that the different clouds provide, that's when it becomes tricky migrating your applications from one cloud to another."
For more on cloud migrations, see Part 1.