mod_unique_id: unable to find IPv4 address of FQDN despite setting etc/hosts and Apache ServerName

Question

I would like to work on a ruby on rails project with a group of 4 people. If we install rails 4.2.0 how can we ensure that we all share the same environment? Is the only option to have install VM? or is there some other way? I mean what if one user is using mac another is on windows and another is on Linux? How can we ensure all are having same environment so there is no configuration issues etc? What is the easiest solution?

Solution 1

The problem was SELinux

#less /var/log/audit/audit.log

type=AVC msg=audit(1311546944.235:1040): avc:  denied  { read } for  pid=1396 comm="httpd" 
name="hosts" dev=dm-0 ino=262931 
scontext=user_u:system_r:httpd_t:s0 
tcontext=system_u:object_r:initrc_tmp_t:s0 tclass=file

In my case the following solved it:

# ls -lZ /etc/hosts
-rw-r--r--  root root system_u:object_r:initrc_tmp_t   /etc/hosts
# setenforce 0
# restorecon -R -F -v /etc/hosts
# setenforce 1
# ls -lZ /etc/hosts
-rw-r--r--  root root system_u:object_r:etc_t          /etc/hosts

Solution 2

I'd be looking for typos and other "stupidly simple" mistakes we all make from time to time (I use my wife as a proof-reader), but if that doesn't work I'd just fire up strace to see what mod_security is trying to do. It might not be reading /etc/hosts -- perhaps it's taking a failure to resolve the name via DNS as some sort of hard failure instead, or something else.

At any rate, I'd be putting the machine's name in DNS anyway. It just saves so many hassles.

Comments

[Marc Baumbach]

You'll have to be more specific, I think. Do you just mean the same database, or do you have external dependencies? Usually making sure you use a SCM tool and Bundler correctly, you should all have the same environment. If your concern is more OS, then a VM like Vagrant or Docker may be your best choice.

[KCD]

Yes I've been struggling to rule out problems existing between the keyboard and the chair. Asking our hosting provider to add the computer name to the DNS would help but it would be nice to know why apache doesn't seem to process the hosts file

[KCD]

Awarded this as the solution because strace identified the true problem and a DNS entry would've solved it either way

[womble]

It'd be worth putting the reason you found in as an answer, for future searchers who come across your question and would like to know exactly what the answer was. I'm curious too, now.

[KCD]

I'm one step ahead of you, see the third section added to the question. SELinux was the problem, I'll edit it to make it clearer. Thanks again for your help!

[womble]

I'm saying make it an answer, not part of your question -- self-answering is explicitly encouraged, as not everyone who finds the question will read the whole question, they'll skim just enough to see that it fits their problem and then skip straight to the answers.

[KCD]

Fair enough. Only reason I didn't do that is so I could credit you with the answer :)

[womble]

I'm wonderfully selfless... although you don't have to take away my precioussssssss accepted tick. <grin>

[KCD]

Ha indeed, chances are you'll answer my next question anyway (note to self - learn about StackExchange 'Chat')

[user1010101]

Is there some free solution available ?

[Amit Joki]

@Learner afaik, I don't know of any free solution to this.

[Antarr Byrd]

@Learner I haven't used it but you may want to look at Runnable

[user1010101]

One of my group member is insisting we all download VM so we have identical vdi image or else it will be an issue. I am new to rails so i wanted to make sure if this is the case.