Friday, 28 December 2018

Starling Bank Hits 100% Sustainable Hosting


Starling is one of the UK’s most successful challenger banks and has been licensed and operating since July 2016. As a branchless, digital and largely paperless bank built in the cloud, in their own words "Starling Bank endeavours to protect the natural environment where it can through practising energy and resource efficiency, recycling and using sustainable waste management". Its ethics statement says the bank is committed to "the pursuit of ecological sustainability and to combating climate change".

Do they live up to that?

Starling are in the fantastic position of already having ~100% of their servers sustainably powered. They have met our goal of 100% sustainable servers by 2024. So yes - I'm impressed.

How on earth have they managed that given their cloud provider, AWS, is only 50% sustainable across their infrastructure??

It’s all about where you host!

Starling’s Infrastructure

Starling operate a backend system talking to apps on their users’ mobile phones and to third party services. Using this they provide a full current account, debit cards, direct debits, standing orders and faster payments to their customers. All of their server instances are hosted on Amazon Web Services (AWS) and have been since day one.

Basically they’re a boring old bank but, not boringly, cloud hosted.

AWS Isn’t 100% Sustainable?!

AWS have a long term commitment to 100% sustainability for their servers but they have no date on that and since January 2018 they have achieved only 50% sustainably powered servers on average. That doesn’t sound too bad but it does mean that their fossil fuel use is growing at the same rate they are. And AWS is growing rather fast.

Nevertheless, although Starling Bank overwhelmingly run their servers on AWS they are entirely sustainably powered. How?

The good thing is, although AWS isn’t 100% sustainable overall they do have four fully carbon neutral public regions: Ireland, Frankfurt, Canada and Oregon.

Where You Host Matters

Every one of Starling’s official instances is in a sustainably-powered European region. That means all of Starling’s servers are clean or at least offset with local clean energy production.

Starling cannot be completely sure that no one in their tech team has ever used an ad-hoc test machine in another region, but the official location of choice is EU-West (Ireland) and that is where all their production servers live.

What about the future? Regulatory requirements and commercial considerations mean they’ll need to diversify into cross-cloud. They are already investigating Google Cloud for that reason. Will that bring their 100% achievement down? Fortunately not. Google Cloud is 100% sustainable across the board, so the machines they operate there, and the additional servers they will run in the future, will maintain Starling’s excellent sustainability score.

It’s Fintech! Why not London Region? 

It is interesting that although Starling is a significant player in London’s Fintech scene, they have no servers in AWS’ London region. A factor in that decision is that London is not one of AWS’s sustainable regions. 

Anne Boden, Starling's CEO, says: "It's important to us that we try to make sure that the power behind our AWS servers comes from sustainable sources."

If you want to read more about their infrastructure, I wrote a Starling Bank case study last year. If you would like to join them in making your servers more sustainable, please sign our “sustainable servers by 2024” petition and read our white paper on sustainable hosting.

Photo by Thought Catalog on Unsplash









Wednesday, 12 December 2018

Ethical Hosting at the FT


Last year, I wrote a case study on the excellent work that the FT have done on exploiting cloud infrastructure. For this follow-up, I talked to them about their progress towards not just fast and reliable systems but ethical and sustainable ones too. They are hopefully on course for meeting our Sustainable Servers by 2024 goal for ethical tech systems - it all depends on some small improvements from AWS.

The FT run over 75% of their compute in AWS cloud regions and are on track to move their remaining on prem servers into the cloud by 2020. At that point, their servers will commendably be nearly 90% sustainably-powered. After that, they would love to achieve 100% by 2024 - but they will need to persuade AWS to not limit some of their vital new services to the comparatively dirty US East region.

As their senior technical architect Rob Godfrey says, “As the FT continue to migrate our on premise infrastructure to the cloud throughout 2019, we will utilise sustainable cloud infrastructure where we can. We would love to see AWS continue to improve the sustainability of their data centres, us-east-1 in particular.”

The Process

Let’s step back and look at the FT’s progress in hosting so far. Historically, like most of us, they started with bare metal servers in their own on-prem data centres (DCs) powered by the UK’s mostly fossil fuel electricity. Again, like many of us their first step towards better utilisation and DC efficiency was on-prem virtualisation (they went for VMWare on Intel). They then experimented with building their own cloud but, in 2013, they chose to start trialling AWS when it became clear it was stable enough and going to provide the functionality they needed. Since then, the FT have been gradually transitioning all their servers from on prem to cloud - a transition they are on target to complete by 2020.

In 2018, around 75% of the FT’s infrastructure is AWS Cloud-based. However, where it is in that Cloud is crucial to its sustainability.

How Clean is AWS?

AWS currently have 4 non-governmental fully sustainable, 100% carbon neutral regions:

  • Ireland
  • Frankfurt
  • Canada
  • Oregon. 

Today, the FT splits their cloud resources roughly 5:1 between bare AWS instances and a Heroku PaaS.

⅙ on Heroku

Heroku's compute is AWS-hosted. ~70% of the FT’s Heroku dynos run in the "EU" Heroku region (which appears to correspond to the 100% carbon neutral Ireland AWS region) and ~30% in the "US" Heroku region (which appears to be on AWS's US East). These are the only 2 common Heroku runtime hosting options - EU (100% sustainable) and US (us-east-1, so ~50%).

⅚ on AWS

For the FT’s ~1250 “bare” AWS instances, they primarily use 2 regions: the sustainable Ireland (EU West) and the vastly less clean US-East. How is this resource divided up and why do they use two different regions?

Most of the FT’s compute is in sustainable EU Ireland, but for their high availability services they split their hosting over 2 regions: Ireland and us-east-1. In addition, they sometimes need to host further instances in US East because AWS still make some new or trial functionality only available in that region. AWS Lambda (Amazon’s Function-as-a-Service platform) for example was originally only available in that one region. As a result ~19% (by cost) of the FT’s AWS infrastructure remains in US East.

Overall Sustainability of the FT Hosting Infrastructure

All the numbers we give here are very approximate estimates, but if we assume that

  • AWS’ US East region is 50% sustainable (a guess based on 50% being AWS’ overall average sustainability and US East being their largest region). 
  • The FT’s legacy DC is 0% sustainable.
  • The FT’s AWS instances are 90.5% sustainable (corresponding to 81% in EU West being fully sustainable and 19% in US-East being 50% sustainable
  • The FT’s Heroku infrastructure is 85% sustainable (corresponding to the 70% in the EU being fully sustainable and 30% in US-East being 50% sustainable.


The result is that we estimate very roughly* 67% of the FT’s infrastructure is currently running on sustainable servers and this will rise to nearly 90% when they have completely transitioned to the Cloud in 2020.

This is good. But how will they get the final 10%? We’d all love it if AWS’s US East went carbon neutral! Failing that, we need to see features only available in that region (like new feature trials) being offered in sustainable regions too, so that clients like the FT could get the sustainable servers they want for the new services they need. 

In summary, the FT are making excellent progress but to get all the way to the all important 100% that they’d love to see, they’ll need some additional help from their cloud providers.

If you’d like to support them and us in our sustainable hosting goals, please sign our petition for 100% carbon neutral hosting targets for our industry.

 *All calculations are approximate.

Photo by Kenrick Mills on Unsplash