Generate no cidfile by default, even when deploying as service.

[jperville]

This PR remove the default value of /var/run/#{service_name}.cid when deploying container as a service. In other words, this means that containers will be deployed without a cidfile unless docker_container is configured with an explicit value for its cidfile attribute.

The main reason for that (slightly breaking) change is that :

• cidfiles are created by default in /var/run which is flushed at every reboot (tmpfs)
• docker start won't recreate cidfiles (only docker run --cidfile will)

My conclusion is that since the cidfiles we generate in /var/run do not survive reboots they cannot be relied upon and should not be generated by default.

My other reasons:

• containers can run just fine without cidfiles
• the service scripts do not use them (fgrep -r cid shows that no code depends on them in the cookbook)
• cidfiles complicate redeploys (docker run won't recreate a named container when there is a stale cidfile, see Removing a container should also remove its cidfile. #164)

In the past I hacked around the cidfile issue by configuring my docker_container resources with cidfile '' but recent dockers (post 0.9) choke when docker run is invoked with --cidfile=''.

[djdefi]

I seem to be having lots of issues with cidfiles also. Even with the 0.35.0 update yesterday that addressed some of the cid issues I am still having to manually delete cidfiles

[fangpenlin]

+1 on disable cidfile by default, it's really annoying. I need to delete it every time before running a container, otherwise it will simply fail.

[bflad]

Personally I'm a fan of removing the cidfiles as well. They are more trouble than they are worth it seems. I'll merge this in and refactor the now extraneous cidfile method out.

[jperville]

Thank you @bflad for the quick merge! I didn't refactor out the cidfile method because I wanted my patch to be as simple and unobtrusive as possible. I'm very happy now :-)

[djdefi]

Awesome, redeploy works great now!

[bflad]

🎉 sweet!