SwiftStack - <a href="http://swiftstack.com/jobs" > - San Francisco, CA (preferred)
We are making running private cloud storage awesome.  Our core product - the SwiftStack Controller - makes it easy to configure, deploy, manage and monitor your own personal Swift[1] cluster.  It's a Django app, with a background task and alerting/eventing engine, a 0mq based remote execution agent to control the fleet, and statsd feeding graphite for telemetry.
But our core deliverable is OpenStack Swift.  OpenStack is the open-source alternative to AWS, and Swift is Object Storage (think S3).  And our team is actively driving new capabilities[2] with the open source community.
Our customers are managing distributed storage systems growing at dozens or hundreds of terabytes a month - we're literally taking on big problems - wanna help?  We're primarily a python shop, actively recruiting Sr. Engineers and opinionated UX designers who have experience working with a Django team - but we've got lots of room for experience at all levels, if you're interested check us out:
<a href="https://swiftstack.com/jobs/" >
[1] Swift: <a href="https://wiki.openstack.org/wiki/Swift" >
[2] Storage Policies in Swift: <a href="https://swiftstack.com/blog/2014/01/27/openstack-swift-storage-policies/" >
Ask HN: Who is hiring? (February 2014)