Hello all,
I have observed a problem with a diskless PXE client I am attempting
to configure. PXE/NFS/DHCP/TFTPd server is running CentOS5.1 and the
Diskless workstation's root and kernel was extracted from a CentOS5.1
(custom kernel due to setting to enable Root File System support).
Problem: When the diskless client boots and logs in I notice that my
root user is being squashed, even if I have exported the root with the
"no_root_squash" option. The exports file contains this line:
/export/images *(rw,no_root_squash,no_subtree_check)
1. Creating a file as root gives it nobody permission:
rw-r--r-- 1 65534 65534 0 Feb 26 16:30 foo
2. When I explicitly mount the same export from the booted
workstation and create another file; this time, it is created as root:
-rw-r--r-- 1 root root 0 Feb 26 16:31 bar
3. I checked the /proc/mounts and notice there are differences in the
NFS options it has accepted during mount:
rootfs / rootfs rw 0 0
/dev/root / nfs
rw,vers=2,rsize=4096,wsize=4096,hard,nolock,proto=udp,timeo=11,retrans=2,sec=null,addr=192.16.10.5
0 0
192.16.10.5:/tftpboot /mnt/test nfs
rw,vers=3,rsize=32768,wsize=32768,hard,proto=tcp,timeo=600,retrans=2,sec=sys,addr=192.168.16.5
0 0
4. I try to append NFS options to my APPEND line to force: NFS
version3, change r/wsize, use tcp protocol and change the sec from
null to sys (null seems to be the parameter that affects the NFS
ownership/permission). My /tftpboot/pxelinux.cfg/default file
contains the following:
nfsroot=192.168.16.5:/export/images/centos51_x86-64,nfsversvers=3,tcp,rsize=32768,wsize=32768,sec=sys
ip=dhcp
5. All options are honored except for the "sec=sys" option. Below is
the output of the /proc/cmdline:
/proc/cmdline:
root=/dev/nfs rw
nfsroot=192.168.16.5:/export/images/centos51_x86-64,nfsvers=3,tcp,rsize=32768,wsize=32768,sec=sys
ip=dhcp BOOT_IMAGE=vmlinuz-2.6.18-custom-2.6.18-53.el5
6. But the /proc/mounts shows that the "sec=" parameter is still set to NULL.
/proc/mounts:
rootfs / rootfs rw 0 0
/dev/root / nfs
rw,vers=3,rsize=3278,wsize=3478,hard,nolock,proto=tcp,timeo=11,retrans=2,sec=null,addr=192.168.16.5
0 0
............
Kernel versions:
PXE server --> uname -a
Linux qatest1 2.6.18-53.1.13.el5xen #1 SMP Tue Feb 12 13:33:07 EST
2008 x86_64 x86_64 x86_64 GNU/Linux
Diskless Workstation's kernel and root are extracted from this: Linux
localhost.localdomain 2.6.18-custom-2.6.18-53.el5 #1 SMP Wed Feb 20
08:45:23 PST 2008 x86_64 x86_64 x86_64 GNU/Linux
Any help would be greatly appreciated.
--
best,
Vince
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