Tuesday, October 17, 2006

Remove node from gfarm 1.3

This instruction apply to Gfarm 1.3.1 using Postgresql backend metadata storage only

1. Remove the node from your cluster. Ex: For NPACI Rocks 4.2
insert-ethers --remove compute-0-7
2. Use psql to access gfarm database. Make sure to change the port number to the correct port. Use 'ps auxw | grep postmaster' to find the port number
psql -p 10602 gfarm farm
3. From psql prompt, input
DELETE FROM filesectioncopy WHERE hostname='compute-0-7.local';
4.Exit from psql. Now the node has been removed permanently from database. Remove it from gfarm now.
gfhost -d compute-0-7.local
That should be all.

Monday, January 16, 2006

5. LVS: The ARP Problem

Another LVS note, in case I would forgot this. This is from http://www.austintek.com/LVS/LVS-HOWTO/HOWTO/LVS-HOWTO.arp_problem.html

5. LVS: The ARP Problem: "2.4.26 and 2.6.4 will come with 2 new device flags for tuning the ARP stack: arp_announce and arp_ignore. All IPVS like setups can use arp_announce=2 and arp_ignore=1/2/3 to solve the 'ARP problem' with DR/TUN setups. These flags are going to replace the 'hidden' functionality which does not work well for directors when they are changing their role between master/slave for a particular VIP. The risk is that other hosts can probe for VIP using unicast packets for which the hidden flag always replies. I'll continue to support the hidden flag for 2.4 and 2.6 to help existing setups but switching to the new device flags (or other solutions) is recommended.

Documentation is in the 2.6 kernel docs (linux/Documentation/networking/ip-sysctl.txt).

arp_ignore: 1 - reply only if the target IP address is local address configured on the incoming interface. if eth0/arp_ignore=1 then all IPs on eth0 are replied, all others (on lo) are not."

Friday, January 13, 2006