Permissions are a pest.
Basically, you need to make sure that all of those developers can write to everything in the git repo.
Skip down to The New-Wave Solution for the superior method of granting a group of developers write capability.
The Standard Solution
If you put all the developers in a specially-created group, you can, in principle, just do:
chgrp -R <whatever group> gitrepo
chmod -R g+swX gitrepo
Then change the umask for the users to 002, so that new files get created with group-writable permissions.
The problems with this are legion; if you’re on a distro that assumes a umask of 022 (such as having a common users group that includes everyone by default), this can open up security problems elsewhere. And sooner or later, something is going to screw up your carefully crafted permissions scheme, putting the repo out of action until you get root access and fix it up (i.e., re-running the above commands).
The New-Wave Solution
A superior solution—though less well understood, and which requires a bit more OS/tool support—is to use POSIX extended attributes. I’ve only come to this area fairly recently, so my knowledge here isn’t as hot as it could be. But basically, an extended ACL is the ability to set permissions on more than just the 3 default slots (user/group/other).
So once again, create your group, then run:
setfacl -R -m g:<whatever group>:rwX gitrepo
find gitrepo -type d | xargs setfacl -R -m d:g:<whatever group>:rwX
This sets up the extended ACL for the group so that the group members can read/write/access whatever files are already there (the first line); then, also tell all existing directories that new files should have this same ACL applied (the second line).
Hope that gets you on your way.
Best Answer
You really would be better off setting up a pair of nameservers if you can. I've never really seen a situation where you couldn't replace a cumbersome hosts file situation with a couple of DNS servers (Really, they are easy to setup and run).
However, to answer your question, you can use something like either puppet or cfengine to keep these in sync.
Another question though... I'm not sure why the first few lines need to change?
127.0.0.1 always points to the local machine and would always be localhost.localdomain localhost
The private IP of the machine will be the same hostname on the machine as it is on every other machine?