Very informative. I only wish there was more time to cover the CI aspect and other deployment tools.
Kris is a great story-teller. I thoroughly enjoyed his talk.
The talk was informative, but some of the visuals were confusing. I personally wish it went into more depth on actual use cases (case studies maybe?).
Based on the types of projects and environments I work with, Docker currently seems more like an interesting experiment or dev tool than something production-ready. I'll be keeping an eye on it though.
Just wanted to give a plug for https://github.com/vend/phanglia - if you're already using Ganglia, this'll send UDP metric packets to gmond, so you won't have to run StatsD *and* gmond.
Also: you might want to mention atomicity. (fwrite in unix is not atomic). That's the idea behind the 'current' symlink pointed at a release: it prevents reads falling between two partial writes. This is especially important with an opcache, where the first read is going to get cached.