Site Reliability Engineers: “solving the most interesting problems”

I recently sat down with Ben Appleton, a Senior Staff Software Engineer, to talk about his recent move from Software Engineer (SWE) on the Maps team to Site Reliability Engineering (SRE). In the interview, Ben explains why he transitioned from a pure development role to a role in production, and how his work has changed:

Chris: Tell us about your path to Google.
Ben: Before I joined Google I didn’t consider myself a “software engineer”. I went to the University of Queensland and graduated with a Bachelor’s Degree in Electrical Engineering and Mathematics, before going on to complete a Ph.D. My field of research was image segmentation, extending graph cuts to continuous space for analyzing X-rays and MRIs. At a conference in France I met a friend of my Ph.D. advisor’s, and he raved about Google, commenting that they were one of the only companies that really understood technology. I’d already decided academia wasn’t for me, so I interviewed for a general Software Engineering role at Google. I enjoyed the interviews, met some really smart people, and learned about some interesting stuff they were working on. I joined the Maps team in Sydney in 2005 and spent the next 6 years working on the Maps API.

Chris: Tell us about some of the coolest work you did for Google Maps, and how you applied your research background.
Ben: My background in algorithms and computational geometry was really useful. We were basically making browsers do stuff they’re not designed to do, such as rendering millions of vectors or warping images, inventing techniques as we went. On the server-side we focused on content distribution, pushing tiles or vectors from Google servers down through caches to the user’s browser, optimizing for load and latency at every stage. On the client-side, we had to make the most of limited processors with new geometric algorithms and clever prefetching to hide network latency. It was really interesting work.

Chris: I understand you received company-wide recognition when you were managing the Maps API team. Tell us more about what that entailed.
Ben: In September 2008, when managing the Maps API, my team received an award that was recognized Google-wide, which is a big honor. My main contributions were latency optimizations, stability, enterprise support, and Street View integration. The award was in recognition of strong sustained growth of the Maps API, in relation to the number of sites using it, and total views per day. Currently the Google Maps API is serving more than 600,000 websites.

Chris: So what prompted the move to Site Reliability Engineering (SRE)?
Ben: In my experience, a lot of software engineers don’t understand what SREs do. I’d worked closely with SREs, particularly those in Sydney supporting Maps, and had formed a high opinion of them. They’re a very strong team - they’re smart and they get things done. After 6 years working on the Maps API I felt it was time for a change. In Sydney there are SWE teams covering most of the product areas, including Chrome and Apps, Social and Blogger, Infrastructure Networking and the Go programming language, as well as Maps and GeoCommerce. I talked to all of them, but chose SRE because in my opinion, they’re solving the most interesting problems.

Chris: How would you describe SRE?
Ben: It really depends on the individual. At one end are the Systems Administrator types, sustaining ridiculously large systems. But at the other end are the Software Engineers like me. As SREs get more experienced this distinction tends to be blurred. The best SREs think programmatically even if they don’t do the programming. For me, I don’t see a difference in my day-to-day role. When I was working on the Maps API I was the primary on-call one week in three, whereas in SRE the typical on-call roster is one week in six. When you’re primary on-call it just means you’re the go-to person for the team, responsible for when something breaks or pushing new code into production. I was spending 50% of my time doing coding and development work, and as an SRE this has increased to 80%.

Chris: Wow! So as an SRE in Production, you’re spending less time on-call and more time writing code than you were as a SWE on the Maps team?
Ben: Yes! I’m not managing a team now, but I’m definitely spending more time coding than I was before. I guess the average SRE spends 50% of their time doing development work, but as I said, it depends on the person and it ranges from 20-80%.

Chris: What does your team do?
Ben: In Sydney there are SRE teams supporting Maps, Blogger, App Engine, as well as various parts of the infrastructure and storage systems. I’m working on Blobstore, an infrastructure storage service based on Bigtable which simplifies building and deploying applications that store users' binary data (BLOBs, or "Binary Large OBjects"). Example BLOBs include images, videos, or email attachments - any data objects that are immutable and long-lived. The fact that we're storing user data means that Blobstore must be highly available for reads and writes, be extremely reliable (so that we never lose data), and be efficient in terms of storage usage (so that we can provide large amounts of storage to users at low cost).

Chris: Tell us more about some of the problems you’re solving, and how they differ with those you faced as a SWE in a development role.
Ben: With the massive expansion in online data storage, we’re solving problems at a scale never before seen. Due to the global nature of our infrastructure, we think in terms of load balancing at many levels: across regions, across data centers within a region, and across machines within a data center. The problems we’re facing in SRE are much closer to the metal. We’re constantly optimizing resource allocation and efficiency and scalability of Google’s massive computer systems, as opposed to developing new features for a product like Maps. So the nature of the work is very similar to SWE, but the problems are bigger and there is a strong focus on scale.

Chris: Are you planning on staying in SRE for a while?
Ben: Yeah. I signed up for a six month rotation program called “Mission Control,” the goal of which is to teach engineers to understand the challenges of building and operating a high reliability service at Google scale. In other words, it’s an SRE training program. In my first three months of Mission Control I’ve been on-call twice, and always during office hours so there were SREs to help me when I got into trouble...which I did. I’ve got no intention of going back to SWE at the end of the six months and plan to stay in SRE for at least a few years. Right now the problems seem more interesting. For example, last year’s storage solutions are facing additional strain from the growth of Gmail, Google+ and Google Drive. So you’re constantly reinventing.

Chris: What advice do you have for Software Engineers contemplating a role in SRE?
Ben: SRE gives you the opportunity to work on infrastructure at a really big scale in a way you don’t get to in SWE. Whereas SWE is more about developing new features, SRE is dealing with bigger problems and more complex engineering due to the sheer scale. SRE is a great way to learn how systems really work in order to become a great engineer.

If you’re interesting in applying for a Site Reliability Engineering role, please note that we advertise the roles in several different ways to reflect the diversity of the team. The two main roles are “Software Engineer, Google.com” and “Systems Engineer, Google.com”. We use the term “Google.com” to signify that the roles are in Production as opposed to R&D. You can find all the openings listed on the Google jobs site. We’re currently hiring across many regions, including Sydney in Australia, and of course Mountain View in California.