Hello everyone,
I have a problem with setting up a diskless system on CentOS. Currently I have successfully set up a small cluster of diskless clients following the following available HowTos: http://wiki.centos.org/HowTos/DisklessClients https://coda.jlab.org/wiki/index.php/CentOS6_Linux_Diskless_Setup
The client system is CentOS 5.10 and the system is read-only. It has been working fine for a while (although I discard some initiation errors, but as of functionality it is working). But recently when I tried to setup autofs to mount some of the directories from NIS server, I've been having problems because /etc/mtab is not writable. I have enabled temporary state in the OS, please find below my /etc/sysconfig/readonly-root: ==================== # Set to 'yes' to mount the system filesystems read-only. READONLY=yes # Set to 'yes' to mount various temporary state as either tmpfs # or on the block device labelled RW_LABEL. Implied by READONLY TEMPORARY_STATE=yes # Place to put a tmpfs for temporary scratch writable space RW_MOUNT=/var/lib/stateless/writable #RW_MOUNT= # Label on local filesystem which can be used for temporary scratch space RW_LABEL=stateless-rw # Options to use for temporary mount RW_OPTIONS= # Label for partition with persistent data STATE_LABEL=stateless-state # Where to mount to the persistent data STATE_MOUNT=/var/lib/stateless/state # Options to use for peristent mount STATE_OPTIONS= CLIENTSTATE=10.0.0.1:/common/diskless/x86/RHEL5/snapshot
Now my solution is making a symbolic link for /etc/mtab to its snapshot in /var/lib/stateless/writable. However, since by default it is mounted on tmpfs instead of NFS, every time the machine reboot, mtab is lost and there are all kinds of problem. So I created another mtab.bak and copy that to the RW_MOUNT when system start. That solves my problem, although I feel the approach is really ugly.
So my questions are below: 1. How to mount my RW_MOUNT on my NFS snapshot directory by default? The instructions are not clear on this part. 2. If I can use NFS as snapshot, how do I tell the system which file I want to use the writable version in RW_MOUNT, is there a more elegant way to do that? 3. Could someone points me some direction or background on the snapshot idea? I've looked into /etc/rc.sysinit and saw the part to mount the stateless directory, but more information could be helpful.
Thank you in advance!
Regards, -- Di Wu (Allan) Center of Domain-Specific Computing http://www.cdsc.ucla.edu/, Department of Computer Science, UC Los Angeles Email: allwu@cs.ucla.edu Phone: 310-982-5215