NAB looks for new ways to measure its cloud migration

NAB wants to move away from quoting the percentage of its application estate migrated to cloud as a measure of success, believing there are now better ways - and metrics - to report progress.

In a new episode to launch the second season of the iTnews Podcast, NAB's chief technology officer Steve Day details shifts in strategic thinking around the bank’s highly-publicised cloud journey, which has been running at scale since 2017.

NAB, which laid a lot of the regulatory groundwork for public cloud adoption by Australia’s banking sector, became known for its frequent presentations on the minutiae of its cloud strategy and progress in the early years.

This has trailed off a bit since, not because the bank is doing anything less exciting or noteworthy in the cloud now, but more because the hype surrounding the program of work has subsided, and running in the cloud at scale is now an operationally normal state of mind.

“Cloud has become part of the furniture - it’s just what we do now,” Day said.

“When banks built their first mainframes and data centres, there was just as much ‘hoo ha’, but we just don't talk about that anymore. It became embedded.

“I'm focused on the cloud every day, of course, but we're not out there publicly talking about what we've been doing consistently now for five years. It would be very boring if we were.

“It’s a five-year program. We're getting on with it, and we're making great progress.”

The bank has now crossed the 60 percent mark in terms of the percentage of its application estate that’s been migrated to run in the cloud, either AWS or Azure.

“The goal is not to get to 100 percent because there are some applications that just make no sense to put into the cloud,” Day said.

“For example, we don't believe that there is a cloud-based platform that is ready yet for running mainframe ledger-based applications.”

Day estimated that somewhere between 10 and 20 percent of its application estate won’t end up being moved to the cloud.

The bank is currently shifting applications into the cloud at a rate of about three a week.

On the surface, this is under the five per week the bank needs to hit a publicly-stated target of shifting 1000 applications to Azure in 1000 days.

But Day said the move to Azure - and to cloud more broadly - is still tracking as expected.

This highlights a challenge for the bank as it moves into the final stages of its journey: percentage of applications or workloads shifted to run in the cloud is an increasingly unreliable indicator of the bank’s progress.

“The whole thing about the percentages is becoming a little bit obscured by our move to new microservices-based architectures,” Day said.

“In terms of just tracking our cloud usage, we're really focused on just getting all of our legacy applications out of that legacy environment and into the cloud.

“Percentage of applications is probably not the right metric [for this] into the future. We’re going to work on a metric that better gives us that measure.”

NAB’s challenge is that it previously ran migration work through “factories” - repeatable processes for simpler applications - or “dojos” for applications that needed more work to make them cloud-ready.

A third path has since emerged, Day said.

“Some of our application migration treatments [now] are not even to try and migrate the application to cloud, but to decommission it and build a new cloud native application instead.”

These cloud-native applications are partially built with reusable microservices.

With cloud-native application numbers rising, the bank increasingly has no way of demonstrating this progress or of folding it into existing public metrics for the migration.

“If I was to count every microservice as an app, we'd be at 95% [of applications migrated to the cloud] now, I think, just because of the sheer number of microservices,” Day said.

“But we haven't done that, and we continue to look at how we would just be able to represent our actual goal of everything we want in the cloud being in the cloud.”

FinOps focused

One aspect of its cloud migration that it has spoken publicly about in 2022 is its work around FinOps to keep its cloud costs in check.

The bank said in February it is “constantly on the hunt for optimisation opportunities across our cloud, whether that’s around rightsizing [or] shutting down temporarily or removing resources that are not used.”

Day said that one of the FinOps controls NAB relies on is “monitoring of the six-hour billing feeds that we get from our cloud providers.”

“They provide almost real-time billing,” he said.

“If something does get spun up very quickly that is spending outside of the process, we use a little bit of machine learning to identify that and to raise flags when it occurs.”

Day said the bank also made sure that development environments were turned off over Christmas, that it made use of spot instances and serverless where possible, and “right-sized” over-specified instances where it made sense.

Another recent change driven by FinOps is a move from EC2 instances running on x86 processors to instances that run on ARM cores.

“We swapped a whole lot of applications to ARM processors, and we were able to do that in days when we realized that ARM processors were now available, reliable, and a fraction of the cost of traditional x86 architectures,” Day said.

“Things like that you just could never do in your own data centre. But with cloud, if you're focused and diligent, and you really pay attention to FinOps, you can take advantage of those sorts of things and end up saving a huge amount of money compared to the old way of doing things.”

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