Logsearch is the opensource project I lead as part of my day job at City Index Ltd. Based on the Elasticsearch ELK stack; and packaged as a BOSH release, it builds you a log processing cluster tailored to making sense of your IT environment and the apps that run on it.
I gave a talk showing how Logsearch can be used to analyse the logs of a Cloud Foundry cluster at the London PaaS Users Group last week that was well received.
Below is a screencast of that Logsearch for Cloud Foundry presentation (youtube)