Gentoo Archives: gentoo-amd64

From: Mark Knecht <markknecht@×××××.com>
To: gentoo-amd64@l.g.o
Subject: Re: [gentoo-amd64] nfs mount has now become read-only
Date: Tue, 04 Apr 2006 22:53:46
In Reply to: Re: [gentoo-amd64] nfs mount has now become read-only by Sami Samhuri
Thanks Sami!

On 4/3/06, Sami Samhuri <sami@××××××××××.com> wrote:
> Mark Knecht wrote: > > Hello, > [...] > > There have been no changes or updates of any kind to the remote > > machine that has the NFS directory exported. Normal updates have been > > occurring on my AMD64 machine so presumably the problem is on this > > machine as none of the remote files are writable anymore. One thing I > > notice is that on the remote machine there are some directories and > > files which have user names and some which only have numbers like 501, > > 502, etc. > > > > Where would I start looking for what's changed? > > The file system stores a user id for the owner and group. ls looks up the user > id in /etc/passwd and shows you the username instead. You can make ls show user > id's instead of names with `ls -ln`.
OK, I basically knew this...
> > When you see numbers such as 501 in the directory listing that means the user or > group who had that user id is not found in /etc/passwd or /etc/group.
OK, that means it's using the passwd file local to that specific machine then. Here's what I have: NFS Server: Only one user account: mythtv:x:1000:100::/home/mythtv:/bin/bash MythTV Backend Server: 3 user accounts: mark:x:500:100:Mark:/home/mark:/bin/bash evelyn:x:501:100:Evelyn:/home/evelyn:/bin/bash matt:x:502:100:Matt:/home/matt:/bin/bash AMD64 machine: 2 user accounts: mark:x:1000:100::/home/mark:/bin/bash matt:x:1001:100::/home/matt:/bin/bash
> > The user id's on all the machines you use with NFS have to be the same. I found > this in the HP-UX documentation via google: > > >>>> From: > > To Set User IDs and Group IDs (if neither NIS nor NIS+ is used) > > * Create one /etc/passwd file and one /etc/group file that contain all the users > and groups on the network, and then copy these files to all the machines on the > network. > > or > > * Edit the /etc/passwd and /etc/group files on each machine to ensure that the > following conditions are true: > > o Each user has the same user ID on all machines where that user has an account. > > o No two users anywhere on the network have the same user ID. > > o Each group has the same group ID on all machines where that group exists. > > o No two groups on the network have the same group ID. > > When users request NFS access to remote files, their user IDs and group IDs are > used to check file ownership and permissions, just as they are locally. > > If a user has one user ID on an NFS client and a different user ID on an NFS > server, the server will not grant the user access to his or her files on the > server, because it thinks the files belong to someone else. > > If a user on one machine has the same user ID as a user on another machine, one > user may gain access to the other user's files. > > >>>> > > Perhaps your user ids don't match. I've been bitten by this before sharing > between Mac OS X, Gentoo, and Ubuntu. Hope this helps.
OK, I think you've hit on a potential problem here. Problem is what is the best way to address this on machines that have been running for a long time? Can I safely edit /etc/passwd and /etc/group and then do chown -R commands to change the ownership of files on the systems after I make all the IDs and groups identical? Thanks, Mark
> > -- > Sam > -- > gentoo-amd64@g.o mailing list > >
-- gentoo-amd64@g.o mailing list


Subject Author
Re: [gentoo-amd64] nfs mount has now become read-only "Conway S. Smith" <beolach@×××××××.net>
Re: [gentoo-amd64] nfs mount has now become read-only Sami Samhuri <sami@××××××××××.com>