Thursday, 29 July 2010

Rocks Cluster NAT

The NAT was not enabled on the cluster to allow nodes access to the public network. This was achieved by editing the /etc/sysconfig/iptables with vim and adding the following lines:-

*nat
-A POSTROUTING -o eth1 -j MASQUERADE
COMMIT


to the beginning of the file.

Save the file using wq

Then restart the service using:-

/sbin/service iptables restart

Then sync the config using :-

rocks sync config

That is now the NAT working and allowing internet access from the compute nodes on the private network.

Rocks Cluster iptables

I needed to modify the iptables to allow connections on some extra tcp ports.
I edited the /etc/sysconfig/iptables file using vim. The extra lines added are shown below:-

# http and https is allowed for all nodes on the public subnet
-A INPUT -m state --state NEW -p tcp --dport 9618 -j ACCEPT
-A INPUT -m state --state NEW -p tcp --dport 9614 -j ACCEPT

The iptables service was restarted using the command /sbin/service iptables restart.

Monday, 5 July 2010

NFS not working on some nodes

NFS not working

The nodes were not working and issuing the command
showed that there was an NFS mounting problem
jimp@compute-2:~$ rpcinfo -p
program vers proto port
100000 2 tcp 111 portmapper
100000 2 udp 111 portmapper
100024 1 udp 52121 status
100024 1 tcp 59769 status


The /etc/hosts file was changed to match the other nodes
the rpcinfo command now gives the following.

jimp@compute-5:~$ rpcinfo -p hadoop
program vers proto port
100000 2 tcp 111 portmapper
100000 2 udp 111 portmapper
100024 1 udp 56797 status
100024 1 tcp 54606 status
100021 1 udp 53628 nlockmgr
100021 3 udp 53628 nlockmgr
100021 4 udp 53628 nlockmgr
100021 1 tcp 53694 nlockmgr
100021 3 tcp 53694 nlockmgr
100021 4 tcp 53694 nlockmgr
100003 2 udp 2049 nfs
100003 3 udp 2049 nfs
100003 4 udp 2049 nfs
100003 2 tcp 2049 nfs
100003 3 tcp 2049 nfs
100003 4 tcp 2049 nfs
100005 1 udp 40126 mountd
100005 1 tcp 37582 mountd
100005 2 udp 40126 mountd
100005 2 tcp 37582 mountd
100005 3 udp 40126 mountd
100005 3 tcp 37582 mountd



Thursday, 1 July 2010

Add User to Sudo users

Add User to Sudo users file

To add user to sudo users file use the command sudo adduser some_user admin. This will allow some_user to issue sudo commands as well as the original sudo user.

File resolv.conf changed on reboot

The file /etc/resolv.conf was being reset and losing the correct nameserver on my Raspberry Pi after a reboot. The unfriendly way of fixing ...