The operations team @ Lumosity (the team I work on) is hiring 1-2 ops engineers! Our ops team currently is 3 people and we are responsible for the smooth operation of lumosity.com for our 50 million users. We use chef, nginx, HAProxy, MySQL (Percona Server), Redis, Memcached, nagios. We run on dedicated hardware at SoftLayer. Lumosity.com is one of the largest consumer rails apps and has a team of really smart engineers and product people building it.
Some things you will be working on: scaling & capacity planning; finding & removing performance bottlenecks; reducing single points of failure; implementing (semi-)automated failover for MySQL/redis/memcached; building a CI system for our chef code, investigating new technologies like Docker to help us spin up infrastructure in less time; being part of our on-call rotation.
We're looking for folks with experienced in both sysadmin & development, but it's totally fine if you know one side and want to learn more about the other :)
Here is the official job description (scroll down):
If you're interested please contact me at firstname.lastname@example.org or apply through that jobvite page and mention HN.
We also have a bunch of other job positions at lumosity.com/jobs for engineers (iOS, Android, Rails, Flash) and others (UX, marketing, internationalization, product management).