Easy Ubuntu Clustering

[apprentice_clusterer]

Hello, bigjimjams and ajt,

thank you both for having explained the problem and for having also suggested a solution.

I will try to put in practise the suggestions.

regards

[robasc]

Well BigJimJams

I did everything you said and I got this error:

trying to load: pxelinux.cfg/default

could not find kernel image: linux
boot:

[robasc]

Hey BigJimJams, I got it to boot and I am logged in to all of my nodes but I am still having some trouble though.

I am trying to use the commands from the setup files for kerrighed and they are not doing anything.

Check to see if nodes in the cluster are running

sudo krgadm nodes

when I try to run this i get command not found

So then I tried to run it chroot /nfsroot/kerrighed and then it says are you sure you want to run kerrighed? and it does not let me type yes or no. It just goes to the command prompt.

I looked at the processes and only seen cpu 1 and 2 running if I am viewing it correctly.

I do not think I understand how to use kerrighed yet.

[Rickles65]

Maybe I'm just thick headed today... So is there nothing out there any more that does process (thread) migration?

We have a need (and it's just 3 machines) for high CPU threads to be moved off to the more idle machines.

We'd done this before (about 5 years ago) with OpenMosix. We just added the appropriate kernel mods, NFS mounts and off we went.

The machines are fully loaded in this config as well so there's no need for SSI in the current config either. Just the net mounts and kernel changes.

[bigjimjams]

Hey BigJimJams, I got it to boot and I am logged in to all of my nodes but I am still having some trouble though.

I am trying to use the commands from the setup files for kerrighed and they are not doing anything.

Check to see if nodes in the cluster are running

sudo krgadm nodes

when I try to run this i get command not found

So then I tried to run it chroot /nfsroot/kerrighed and then it says are you sure you want to run kerrighed? and it does not let me type yes or no. It just goes to the command prompt.

I looked at the processes and only seen cpu 1 and 2 running if I am viewing it correctly.

I do not think I understand how to use kerrighed yet.

Hi Robasc, it might be the case that the kernel was built but the tools were not. What is in the contents of /usr/local/bin on the nodes? Also, are you using the svn version of kerrighed? If so, did you create the /config directory, modify the fstab of the nodes, and configure the new scheduler that kerrighed uses by running sudo krg_legacy_scheduler? Can you give us the tail of dmesg from one of the nodes.

[jbbjshlws]

Hello all!,

Firstly i would like to say fantastic guide, it has helped a lot.

I have ran into a few problems, but nothing a google search didn't find (the problems are/were moslty from lack of experience with linux).

The problem i am facing now that google couldnt help out with is this error after i have pxe booted the client node:


Gave up waiting for root device. Common problems:

-Boot args (cat /proc/cmdline)
-Check rootdelay= (did the system wait long enough?)
-Check root= (did the system wait for the right device?)
-Missing modules (cat /proc/modules; ls /dev)
ALERT! /dev/nfs does not exist. Dropping to a shell!


I have read through and seen that robasc has had this same error, but i didn't see any solution to the problem. My setup differs from Rob's in i am running all i386 32 bit machines, and stayed with the suggested:
$ sudo apt-get install debootstrap
debootstrap --arch i386 hardy /nfsroot/kerrighed http://archive.ubuntu.com/ubuntu/

for the bootable file system.

I am not sure why i am getting this error, and any help would be greatly appreciated. let me know if you need any logs (and let me know how to get them...lol)

Cheers,
Josh

[bigjimjams]

Hello all!,

Firstly i would like to say fantastic guide, it has helped a lot.

I have ran into a few problems, but nothing a google search didn't find (the problems are/were moslty from lack of experience with linux).

The problem i am facing now that google couldnt help out with is this error after i have pxe booted the client node:


Gave up waiting for root device. Common problems:

-Boot args (cat /proc/cmdline)
-Check rootdelay= (did the system wait long enough?)
-Check root= (did the system wait for the right device?)
-Missing modules (cat /proc/modules; ls /dev)
ALERT! /dev/nfs does not exist. Dropping to a shell!


I have read through and seen that robasc has had this same error, but i didn't see any solution to the problem. My setup differs from Rob's in i am running all i386 32 bit machines, and stayed with the suggested:
$ sudo apt-get install debootstrap
debootstrap --arch i386 hardy /nfsroot/kerrighed http://archive.ubuntu.com/ubuntu/

for the bootable file system.

I am not sure why i am getting this error, and any help would be greatly appreciated. let me know if you need any logs (and let me know how to get them...lol)

Cheers,
Josh

Hi Josh, is this with the standard Ubuntu kernel, rather than the kerrighed kernel? If so, then I can only suggest that the problem may lie in the /etc/exports file or in the /srv/tftp/pxelinux.cfg/default file. Can you put the contents of both files on here to see if I can spot something out of the ordinary. However, if this is using the kerrighed kernel, have you made sure to include the drivers for your network card and nfs when configuring the kernel? Hope this may lead in the right direction.

[jbbjshlws]

Hello bigjimjams!
I have followed the how to guide exactly step by step, i am very new to linux so i am nost 100% sure what kernal has been used, but it should be exactly what was in your how to.

Now the default contents of etc/exports is:

# /etc/exports: the access control list for filesystems which may be exported
# to NFS clients. See exports(5).
#
# Example for NFSv2 and NFSv3:
# /srv/homes hostname1(rw,sync) hostname2(ro,sync)
#
# Example for NFSv4:
# /srv/nfs4 gss/krb5i(rw,sync,fsid=0,crossmnt)
# /srv/nfs4/homes gss/krb5i(rw,sync)
#
# /etc/exports #
/nfsroot/kerrighed 192.168.1.0/255.255.255.0(rw,no_subtree_check,async,no_root_sq uash)

and the contents of /srv/tftp/pxelinux is:

LABEL linux
KERNEL vmlinuz-2.6.27-7-generic
APPEND root=/dev/nfs initrd=initrd.img-2.6.27-7-generic nfsroot=192.168.1.1:/nfsroot/kerrighed ip=dhcp rw

I am able to boot through to where it says:

ALERT! /dev/nfs does not exist. Dropping to a shell!

Now i have looked and i do not have /dev/nfs in either the root of my file system or at /nfsroot/kerrighed/dev/nfs for the bootable file system, is this normal?

if it helps i am using 2.6.27-7-generic as my ubuntu instalation, i havn't upgraded to 2.6.27-11-generic, as i figured this could throw more spanners in the works.

I can give you my msn details if it would help speed things up with communication, i will then transcribe the solutions to this forum

[bigjimjams]

Hello bigjimjams!
I have followed the how to guide exactly step by step, i am very new to linux so i am nost 100% sure what kernal has been used, but it should be exactly what was in your how to.

Now the default contents of etc/exports is:



and the contents of /srv/tftp/pxelinux is:




I am able to boot through to where it says:


Now i have looked and i do not have /dev/nfs in either the root of my file system or at /nfsroot/kerrighed/dev/nfs for the bootable file system, is this normal?

if it helps i am using 2.6.27-7-generic as my ubuntu instalation, i havn't upgraded to 2.6.27-11-generic, as i figured this could throw more spanners in the works.

I can give you my msn details if it would help speed things up with communication, i will then transcribe the solutions to this forum

Hi Josh, I think I may have just spotted a mistake in the guide. In /etc/exports the ip address should read 192.168.1.1/255.255.255.0 and not 192.168.1.0/255.255.255.0 as it states. This is then the same as the ip address in /srv/tftp/pxelinux.cfg/default which states where to get the nfsroot from. Hope this helps.

[jbbjshlws]

Hello,
I have changed the ip address to match the ip of the server in both of those files, but i am still getting the same error:

ALERT! /dev/nfs does not exist. Dropping to a shell!

I will double check all of the other files used are referring to the same ip address. could anything else be causing this problem?

do i need to repeat any of the steps now that i have changed the values in those files (besides restarting the daemon's)?