[TriLUG] Rsync

[Aaron S. Joyner]

Stephen Hoffman wrote:

>Probably been asked a hundred times before, but I'm having trouble with
>rsync.
>
>I want to sync two webserver directories on two different machines, but
>the permissions are driving me up a wall.  I've googled, and rtfm to no
>avail.
>
>I run the following command:
>rsync -avre ssh /path/to/local/dir user at host.com:/path/to/remote/dir
>
>this goes through the process of syncing just fine, the issue is that the
>webserver on local machine runs as apache so user:group are apache:apache,
>the user:group on the remote machine are user:nobody.  What is happening
>is when I rsync the two then all the uid's:gid's on the remote machine
>become apache:apache and thus apache can't access the directories.
>
>I've added the -o and -g, but unless I'm reading wrong they do what is
>already happening and transferring the owner and group to the new machine.
>
>I'm working around this by ssh'ing in and chown'ing everything at the end
>of the script, but I would think that this should be a native capability
>of rsync and wouldn't need to be scripted.
>
>TIA,
>Steve
>  
>
The native capability of rsync is to allow you to keep the same UID/GID 
when you rsync the files.  Optionally, you can leave them the same as 
they are on the remote machine for files that are already in place (by 
not specifying anything).  What's not natively supported by rsync, that 
you want, is to change the UID/GID on the fly to something totally 
different on the other machine.  The crux of the problem is that you're 
trying to sync files between two Apache processes that are running as 
different users.  You are already using the best work around that I 
would suggest, which is chown'ing them after the transfer.  As a real 
solution, you could coordinate the UID / GID of Apache on the two 
servers, so that they are the same (presuming that is under your 
control).  That would alleviate the problem more directly - albeit with 
more *actual* work to be done in making those changes.

Another work around that just came to mind, is to create an apache user 
and group on the destination machine, and give them the same UID / GID 
as the nobody : <whatever> - then rsync might inadvertently "do the 
right thing".  Please test, I am not certain if that'll actually do what 
it sounds like it should.  :)

Aaron J.