Right. I interviewed for SRE at Google. It's basically a sysadmin job. You're expected to be proficient at scripting in some language (Python, Perl, bash, etc), but I would assume you're not expected to write code for most Google applications.
I would think the senior SRE engineers know enough about the code base to poke around and make suggestions ("found a bug in module.py at line XYZ that causes bad performance when thousands of users hit it"), but I got the impression that most of their top developers probably would be bored in SRE.
The thing that is ironic is that most of the people interviewing me were not in SRE, but were pure developers. How many companies do you know that let the developers interview sysadmins? I had guys asking me CompSci questions I hadn't heard since college. If the tables were turned, do you think I'd be asking a prospective developer a question about how to configure DRBD replication and heartbeat from one Linux server to another? Even though some devs might know these things from hobby-like experimentation in their free time, they are not going to be doing it on a day to day basis.
It just strikes me as a very broken interviewing system when you have developers interviewing sysadmins.
An important distinction that's missing in this discussion is that you can be either an SA-SRE or a SWE-SRE. You can figure out which is which from how the SRE job postings on google.com are phrased.
SWE-SREs have to pass SWE interviews. I work down the hall from Tim. Nobody keeps track of who came in through which side (SA or SWE), but some of the SREs I work with wrote large parts of the services they support.
Not entirely true. There are two sides to the SRE positions. The sysadmin side is indeed what you say they are, they work on the systems keep them running and do hardware related tasks as well as UNIX level tasks.
The software engineering SRE's work on products to make sure they are ready to scale or if something fails to fix the point of failure. They work alongside the product development teams to make sure the product is stable in production.
The two positions require two different skill-sets (I was interviewed for both sides of SRE). One requires very much computer science, data structures, programming languages, and all of those, the other sysadmin requires more knowledge about Linux, its internals, and the command line interface.
