[Fab-user] Parallel operations for container creation

[Ian Stokes-Rees]

I have read http://docs.fabfile.org/en/1.6/usage/parallel.html and many threads on this topic, but I thought I'd try in my own way to phrase what I believe must be a common situation for many people.

Short version:

For simplicity, imagine a case with 3 VZ containers that I am trying to provision on the same container host.  Right now I have to start 3 terminals, and I execute in each one of them:

fab -H host --name container-1 --index 1 --mode prod --user jdoe
fab -H host --name container-2 --index 2 --mode prod --user jdoe
fab -H host --name container-3 --index 3 --mode prod --user jdoe

I would much rather execute something like:

fab -H host -P --name container-1, container-2,container-3 --index 1,2,3 --mode prod --user jdoe

And have fab auto-magically map that one-liner to the 3 commands above and run them in parallel.  That *seems* like a reasonable request, but I just can't find a way to make that happen.  It is important enough for my work that I'd be willing to write some @map decorator or similar to facilitate an implementation.

For a few more details, each container creation takes ~15 minutes.  They parallelize almost perfectly, so rather than waiting 5 hours for 20 containers to all come up serially (20 x 15 minutes), I'd rather wait 15 minutes.  There are some slight parameter differences for each container.  Right now I need to start 20 terminal sessions and execute 20 slightly different commands.  Error prone!

TIA

Ian