Fabric Env.hosts Not Being Identified

I have a simple fabfile by the name env_fabfile.py # env_fabfile.py # makes use of fab env variables from fabric.api import env, run def login(): env.hosts = ['user@host1:12

Solution 1:

The short answer is that you shouldn't set the env.hosts value the way you are currently doing, and env.passowrds is super-sketchy (broken maybe?), and it's recommended to use SSH key-based access, especially leveraging native SSH config files.

Here's the modified version of your timecal.py script which works as expected, and I'll call out some of the differences below.

# timecal.py# runs the fabfile once in serial and calculates the time# then runs the same file in parallel and calculates the timefrom fabric.api import env, run, execute, parallel
import time

env.use_ssh_config = True
env.roledefs = {
    "my_servers": ['server_1', 'server_2']
}


defrun_lsb_release():
    print"in run"
    run('lsb_release -a')


defdo_task(task_func):
    start_time = time.time()
    execute(task_func, roles=['my_servers'])
    elapsed_time = time.time() - start_time
    return elapsed_time


if __name__ == '__main__':
    print"Running in serial mode "print"Total time taken ", do_task(run_lsb_release)

    print"Running in parallel mode"print"Total time taken ", do_task(parallel(run_lsb_release))

The main difference is using env.roledefs, and the SSH config file, rather than hosts & passwords. Those values will NOT work in the parallel execution mode, due to the fact that those tasks are executed in separate threads. The docs are a little thin, but that's basically why you're having this problem.