暴发户任务阻止工作开始

Question

I have task A and job B. Here are couple oversimplified examples.

task-a.conf

start on startup and starting job-b
console log
task
script
    logger "hello"
end script

job-b.conf

start on (runlevel [2345]
          and stopped networking)
stop on starting rc RUNLEVEL=[016]
console log
script
        logger "world"
end script

Task A needs to run once, before job B starts. When the system starts up, all is well and task A fires, and job B starts. But when manually stopping job B and starting it again, it waits forever. I'm missing something here, but how do I get task A to fire once before job B, but not have job B be blocked forever by task A on additional stop/start actions? I can not change job B to check for task A to have stopped. In certain implementations, task A may or may not be there.

This is on Ubuntu 12.04 with latest updates. Thanks.

Answer 1

The starting stanza was blocking my job from completely starting. In the example given above, job-b is blocked until task-a has completed. Unfortunately task-a is waiting for the startup event, which has long passed.

The solution was to remove the wait for the startup event. Next I wanted task-a to run, but only once per boot. For this I added a pre-start script which checked to see if /run/.task-a existed. If it did not, then task would run and create /run/.task-a. Any time job-b would be started again, it would check for /run/.task-a and then exit since it existed. You can also create a job that runs indefinitely, see /etc/init/network-interface-security.conf.

start on startup and starting job-b
console log
task
pre-start script
    if [ -e /var/.$UPSTART_JOB ]; then
        stop; exit 0
    fi
end script

script
     logger "hello"
end script

post-start exec touch /var/.$UPSTART_JOB