Apache + passenger - /tmp permission denied - ruby-on-rails

Question

I am trying to run ruby on rails under passenger with apache2 under fedora 19 and I got this error in log:
[Tue Feb 25 09:37:52.367683 2014] [passenger:error] [pid 2779] ***
Passenger could not be initialized because of this error: Unable to
start the Phusion Passenger watchdog because it encountered the
following error during startup: Cannot change the directory
'/tmp/passenger.1.0.2779/generation-1/buffered_uploads' its UID to 48
and GID to 48: Operation not permitted (errno=1)
That directory (/tmp/passenger.1.0.2779) doesn't even exist. I think that problem is with selinux. I tried to solve it about 4 hours. Httpd is running under user apache and group apache, I tried:
cat /var/log/audit/audit.log | grep passenger | audit2allow -M
passenger semodule -i passenger.pp
but still nothing.

Answer 1

In your case, you should switch SELinux into Permissive mode at first, then try to capture the audit log from starting Apache to run your application.1
Once you got the home page of your application, you can build your custom policy with the logs.
Switch SELinux into Permissive mode and clean audit.log
]# setenforce 0
]# rm /var/log/audit/audit.log
]# service auditd restart
Restart Apache
]# service httpd restart
Try to open your application with a web browser
It might give more information about what is happenning when you application is running.
Make a custom policy module to allow these actions
]# mkdir work
]# cd work
]# grep httpd /var/log/audit/audit.log | audit2allow -M passenger
]# ls
passenger.pp passenger.te
Load postgrey policy module using the 'semodule' command into the current SELinux policy:
]# semodule -i passenger.pp
]# setenforce 1
Restart Apache
]# service httpd restart
References:
http://wiki.centos.org/HowTos/SELinux#head-faa96b3fdd922004cdb988c1989e56191c257c01

Answer 2

I ran into a similar error, with a startup error about being unable to create a directory that did not exist. (logs, not tmp, but same sort of thing) I, too, battled with it for an hour and couldn't make sense of it. I created/deleted/chmod the directory many ways without success.
The fix for me was to change the parameters to passenger-start. Initially, my Docker container started passenger with:
exec bundle exec passenger start --auto --disable-security-update-check --min-instances 20 --max-pool-size 20 --max-request-queue-size 500
I removed all parameters, leaving just this:
exec bundle exec passenger start
At this point, passenger could create the log folder and file, and all was well. I could have restored the params at this point, but we decided they were not needed for the development environment so left them out moving ahead.
In hindsight, I have a hunch that I deleted the log directory while a file in it was still open, and the file system persisted that condition in some way. But that's just a hunch. Perhaps simply rebooting my Mac would have fixed it...