There are two deployment models: push and pull. In a "Pull" deployment model, the individual servers contact a master server, download their configuration and software, and configure themselves. In a "Push" model, a master server pushes the configuration and software to the individual servers and runs commands remotely. While neither technique is right or wrong, they both have some specific advantages and disadvantages that you should understand when making a decision. In the ruby hosting world, an example of a "push" deployment is heroku , while Engine Yard is an example of a "pull" type deployment. In the Pull model, each server has information about how to obtain it's configuration, when it boots (or whatever the configuration triggering event happens to be) it can continue to proceed without intervention from the master server. In the Push model, because the master server is orchestrating things, it will typically need to have a c
I keep seeing people (especially in the scala/typesafe world) posting about async jdbc libraries. STOP IT! Under the current APIs, async JDBC belongs in a realm with Unicorns, Tiger Squirrels, and 8' spiders. While you might be able to move the blocking operations and queue requests and keep your "main" worker threads from blocking, jdbc is synchronous. At some point, somewhere, there's going to be a thread blocking waiting for a response. It's frustrating to see so many folks hyping this and muddying the waters. Unless you write your own client for a dbms and have a dbms that can multiplex calls over a single connection (or using some other strategy to enable this capability) db access is going to block. It's not impossible to make the calls completely async, but nobody's built it yet. Yes, I know ajdbc is taking a stab at this capability, but even IT uses a thread pool for the blocking calls (be default). Someday we'll have async databa
I've just spent some time setting up a bare Centos 7 image to support development stripping out as much as possible. While CoreOS is probably a better choice, we run redhat in production at this point and centos is a better fit for the time being. The problem I've found is that many of the instructions available via google were written against prerelease versions or espouse manually installing random rpms instead of just using yum. While I get this "works", I'm not a huge fan of this approach and would rather do everything with the package manager. After a LOT of scouring and trial and error, I finally found the "magic" combination. The winner is courtesy of http://www.pc-freak.net/ . I've taken these instructions and tweaked them slightly for my purposes. The original poster did this on a more "full fledged" version of centos with a windows host and my instructions are for a minimal install using and OSX host (though I'm certa
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