2009/11/14

Using the EC2 API: console output blank, connection refused, socket timeout, etc.

Hello there. As usual, there's a world of difference between the conceptual usage of an API and it's real-world, practical stuff. In my adventures I'm stubbornly, block-headedly not interested in using EC2 via anything except the API, i.e. no command-line tools or management console (except for debugging), and so, I intend to be able to create my images etc. in a test-harness. For reasons to be enumerated anon. Anyway, the following stuff may be useful to people writing code that uses the EC2 API for the first time:
When booting an instance, it is not assumed that once it is "running", that SSH will be serving on port 22, neither can it be assumed that the console output is there. So if you want to SSH into your instance, first poll the instance state, and once it's "running", then poll on console output. Once it's there, it's complete, so you can retrieve the fingerprints and go on from there.
This is good to know of course if one wants to sling instances around, but I find it slightly incongruous is that I'm being charged for about a minute of time on a machine I can't access yet. Of course, from Amazon's perspective the instant (har) I'm blocking a slot on a server, then it's chargeable, so it makes sense from their perspective I guess.

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