Tag Archives: fabric

Mass Deployment

One Teletype to Bind Them (Or, Clustered SSH for OS X)

When working at scale, and particularly with hosts that need to have the same configuration or you want to perform the same queries on, the issue becomes how do I ‘reach out and touch’ my fleet? Without centralized infrastructure backed by a messaging broker or a heavier process that leaves hooks in systems and/or requires its own domain specific language, sometimes you can get by with… plain ol’ ssh. Apple Remote Desktop can take us a lot of the way there, and one of the announced features of Mountain Lion is that screen sharing gets another piece of ARD’s pie, the ability to drag-and-drop files to transfer them to the remote machine. But when trying to use features other than screen control, ARD has been found to be hit-or-miss (or misreporting the functionality of hosts) in some circumstances.

csshX in action

‘Scripty’ folks look at these issues and craft tools to meet the challenge-slash-obscure-use case. Perl has long been relied upon for network-aware utilities, and csshX is a tool for managing a ‘cluster’ of ¬†ssh sessions¬†on the Mac. You can download or checkout the code from its googlecode site, and it has a man page that can be accessed when calling the binary directly with the -m switch. Options include telling it the login and/or password to use, feeding it a text file of hosts to access, or merely list hosts by DNS name or IP with spaces in between. Even if user names or passwords are different, fully-functional windows open as it attempts ssh connections to each host, with a red window you can use to control them all once you’ve authenticated to the ssh sessions.
From that point on, the world is your proverbial jerry-rigged oyster! To mimic ARD’s file transfers you could scp back to your machine (as kludges go, smileyface,) and another random tip: using the emacs readline functionality to jump to the beginning of a line with Ctrl-a still works, even though csshX uses that for a special purpose (as does the terminal multiplexer screen,) simply hit Ctrl-a again and the program will understand you wanted to send that to the remote sessions. Enjoy!