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My application is built with three distincts servers: each one of them serves a different purpose and they must stay separated (at least, for using more than one core). As an example (this is not the real thing) you could think about this set up as one server managing user authentication, another one serving as the game engine, another one as a pubsub server. Logically the "application" is only one and clients connect to one or another server depending on their specific need.

Now I'm trying to figure out the best way to run a setup like this in a production environment.

The simplest way could be to have a bash script that would run each server in background one after the other. One problem with this approach would be that in the case I need to restart the "application", I should have saved each server's pid and kill each one.

Another way would be to use a node process that would run each servers as its own child (using child_process.spawn). Node spawning nodes. Is that stupid for some reason? This way I'd have a single process to kill when I need to stop/restart the whole application.

What do you think?

Claudio
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3 Answers3

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If you're on Linux or another *nix OS, you might try writing an init script that start/stop/restart your application. here's an example.

Levi Campbell
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Use specific tools for process monitoring. Monit for example can monitor your processes by their pid and restart them whenever they die, and you can manually restart each process with the monit-cmd or with their web-gui.

So in your example you would create 3 independent processes and tell monit to monitor each of them.

Tobias P.
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  • Unfortunaltely this is not quite answer the question. I need the servers to be always part of the same "start/stop/restart" process. Also, there might be some sort of order in which they are started... This is why I'm talking about "3 servers as 1" :) – Claudio Aug 31 '11 at 12:06
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    then create one application (supervisor) which is a starter of all three applications. when one nodejs process dies you will get an error callback and you're able to restart all three processes. – Tobias P. Sep 03 '11 at 21:44
  • Tobias, I indeed ended up doing something like that. See my answer :) – Claudio Sep 06 '11 at 09:04
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I ended up creating a wrapper/supervisor script in Node that uses child_process.spawn to execute all three processes.

  • it pipes each process stdout/stderr to the its stdout/stderr
  • it intercepts errors of each process, logs them, then exit (as it were its fault)
  • It then forks and daemonize itself

I can stop the whole thing using the start/stop paradigm.

Now that I have a robust daemon, I can create a unix script to start/stop it on boot/shutdown as usual (as @Levi says)

See also my other (related) Q: NodeJS: will this code run multi-core or not?

Community
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Claudio
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