[syslinux] PXE client is root squashing ...

[vincenzo romero]

Hello all,

Though the question is NFS-related, it is in conjunction with the PXE booting.

Issue/Scenario:
- PXE/DHCP/NFS and tFTP server running CentOS51 and is configured per
PXE/Syslinux and RHEL diskless workstation documentation.

1.  Attempt to test ability for client to PXE boot over the network
and run Root-NFS
2.  NFS export in the PXE server is:

#
# NFS Export Files for qatest1 host
#
/export/images                  *(rw,sync,no_root_squash)
/tftpboot               *(rw,sync,no_root_squash)

Note - We want the client to mount the export - with "no_root_squash"
.. it is for a test environment hence we would like to have the client
root possess effective ROOT permission.

3.  Client boots successfully via PXE and mounts the Root FS; however.

Problem:  The diskless client did not seem to mount the export with
"no_root_squash" option.  Whenever I touch a file, it assigns the file
as user nobody;  I noticed this because of boot-up errors stating
inability to write to various /var log files.

In further troubleshooting, I noticed the following in the cat
/etc/proc/mounts (while comparing to manually mounting an NFS export
in the command line while within the diskless client prompt:

# cat nfsmounts2.txt
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

** the above reflects configuration for my root-nfs mounted FS;  the
following below reflects configuration of an NFS client mount
performed manually by myself within the diskless client - after
reboot:

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
.......

1.  When I manually mounted the client to "/mnt/test" - the
"no_root_squash" parameter was enabled.  I am able to perform tasks as
effective root

2.  However, my Root-NFS client mount does not.

Question:  - Where can I change the default NFS client options within
PXE configuration?  I attempted to pass various parameters in the
/pxelinux.cfg/default file - in the APPEND line - to test whether I
can send NFS options through this file, and I am unable to.  I tried
to change NFS version to force it to run NFS version 3, I tried to
change sec=sys (as opposed to what seems to be a default parameter it
passes on - sec=null -)

Can some please shed some light and be so kind to advise on how the
NFS client is mounting in PXElinux when it attempts to mount the
Root-NFS?

thank you in advance.
-- 
best,

Vince