I'm confused. Can someone explain to me why this is so obviously interesting, yet not worth discussing, that it stands - as of 2 hours after submission - at 75 points with zero comments?
Honestly, I've never heard of either company, although I obviously wish them the best of luck. Am I just out of touch?
To understand the interest, you need to understand the moving parts:
Logstash is a sort of pipeline for data you want to log: you can define multiple inputs, transform/filter the data, and then define multiple outputs.
Example 1: read in your apache logs (input), attach geoip data (transform), and then push the resulting data to elasticsearch (output).
Example 2: read from syslog (input), grep on the input to ignore certain files (filter), then push to graphite for graphing (output).
you can have multiple inputs, multiple transforms/filters, and multiple outputs. You can also chain logstash instances together, so you can have "roll up" logs. Logstash itself is a bit heavy in terms of CPU/RAM (it is written in Java), so there are a few, lighter weight "shippers", and you can ship into a Redis instance to proxy events.
Elasticsearch is a java-based search engine with a great REST API and a _lot_ of features. It is built on top of Lucene. It doesn't have a built in GUI. It also scales out super easily.
Kibana is front-end to Elasticsearch, which lets search/visualize your log events.
Ok, those are the parts, why this is interesting: As other commenters have pointed out, this is a powerful combination for understanding your log data. You can ship logs from apps, services and hosts, visualize what's going on, search, correlate, etc.
There's always something to learn and there's always somet technology or company we don't know (yet).
Of the three, you should at least could have heard of ElasticSearch: it is a general purpose search server based on Apache Lucene like its cousin Apache SOLR (maybe you know it), but with REST API, JSON support etc..
You can use it for searching stuff and one (but not the only one) scenario is logging. In this case you use some other software (like Logstash but I think there are others too) to collect logs from different sources (i.e. syslog for operating systems, ruby apps via gems, raw tcp etc..) and according to a friend of mine that uses it for this purpose it's very good for its speed, easy to use, to scale etc..
N.B. I invite anyone more expert to elaborate/correct what I've said, I've just used Apache SOLR in the past and never tried ES
I think any of Logging/Monitoring/Metrics at scale can be thought of as Chicken & Egg problems.
They are important, hard to do well and have a bad habit of only causing issues which swallow engineering time when you are firefighting furiously trying to scale core services.
That's why as someone pointed out separately Spunk is a $5Bn company and people who have had these problems previously are very excited by this news.
(It's also why StatsD&Graphite/OpenTSDB, Riemann/Sensu etc etc are all super interesting)
Honestly, I've never heard of either company, although I obviously wish them the best of luck. Am I just out of touch?