Not sure if RHEL-3 has this but on RH9 there the command called sysctl which lets you force the kernel to use IGMP v2 at runtime. (so no patching is involved)
Cheers, Bernard > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On > Behalf Of Jason A. Smith > Sent: Wednesday, June 23, 2004 15:15 > To: Peter Schmid > Cc: Steve Gilbert; Ganglia General > Subject: Re: [Ganglia-general] Problem with multicast (I think) > > I have also had igmp v3 problems here. In one multicast > group I tried having some nodes running RHEL-3 and others > running RH-7.3. The Enterprise kernel does igmp v3 by > default and is supposed to fall back to igmp v2 if it doesn't > get a response. That doesn't appear to be happening here > with our network setup, which doesn't support igmp v3, see > this bugzilla report: > > https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=125570 > > There is a kernal patch that can allow you to force the > kernel to use igmp v2 but RedHat doesn't want to apply it to RHEL-3 > > > A while ago we also had another igmp problem that we were > never able to solve. We purchased some new nodes for our > clusters that were also attached to a new switch that had > trunks connecting it to the other switches in the same > subnets. For some unknown reason the igmp packets were not > being sent between the two switches. This would cause a > split in the multicast groups if a node on one side of the > trunks was rebooted or gmond was restarted. Basically the > nodes on each side of the switch would see each others > multicast, but not see across the trunks. Our network guy > tried fixing this with help from our Cisco tech rep, but > eventually gave up and we ended up disabling igmp on our > switches. It wasn't really doing much for us anyway since > only our cluster nodes are connected to them and we obviously > want each node to be in the ganglia multicast group, which is > the only thing that is using multicast. > > ~Jason > > > On Wed, 2004-06-23 at 17:55, Peter Schmid wrote: > > Are these new machines a different OS. I've been battleing > the IGMP > > v3 issues here.... and if the OS kernel is set for IGMP v3 and the > > switch only does v2.. or if it does v3 and the > include/exclude groups > > are not setup right.. then your behavior is just what you will see. > > > > HTH, > > > > Pete. > > > > On Wed, 23 Jun 2004, Steve Gilbert wrote: > > > > > Howdy Gangliati, > > > > > > I'm having a strange problem that seems to be with multicast, but > > > I'm not really sure. I had a very similar problem in the > past and > > > posted here about it...that turned out to a be a problem > on one of > > > the network switches, but my network team insists that > this is not the same issue. > > > > > > I'm running Ganglia 2.5.4 (need to upgrade, I know) on about 16 > > > different clusters/subnets of ~200 hosts each. Each subnet has a > > > "control" host that also runs gmond as well as named, > ypserv, dhcpd, > > > etc. I have a central monitoring host that is dedicated > to running > > > gmetad and the webfrontend that talks to the 16 different > control nodes. > > > Hope that makes sense. We've been running this way with no major > > > trouble for quite a while. > > > > > > I recently brought a new subnet/cluster online, and now > I'm having > > > trouble. The control box on this subnet seems to be > isolated from > > > the rest. gstat --all only shows itself, not the rest of the > > > subnet. The rest of the subnet sees everything except > this control box. > > > > > > I've rebooted all the machines as well as restarted all gmonds > > > several times. When you first start up gmond on the > control box, it > > > only sees itself...then some random amount of time later, it will > > > list the other nodes in the subnet as being dead. Similarly, the > > > other hosts report the control box as being dead. I can point my > > > gmetad to a random node in the subnet, and that works > fine...I just > > > can't get the control box to be part of the cluster. So > it seems to > > > me that they do communicate at some point to at least > populate the > > > dead list. I've done tcpdumps looking for multicast > traffic between > > > the control box and the rest, but nothing ever shows up. > > > > > > The control box is on a different physical network segment...the > > > nodes are plugged into 48-port Cisco switches (100 Mb), and those > > > have a GigE connection back to a big Cisco 6500. The control box > > > has a direct GigE connection to the 6500. Same deal as > with all our other subnets. > > > > > > I'm no network whiz, but I've had our network team beating their > > > heads against this, and they insist there is nothing > wrong on their end. > > > Anyone else have any ideas? Thanks! > > > > > > > > > Steve Gilbert > > > Unix Systems Administrator > > > [EMAIL PROTECTED] > > > > > > > > > ------------------------------------------------------- > > > This SF.Net email sponsored by Black Hat Briefings & Training. > > > Attend Black Hat Briefings & Training, Las Vegas July 24-29 - > > > digital self defense, top technical experts, no vendor pitches, > > > unmatched networking opportunities. Visit www.blackhat.com > > > _______________________________________________ > > > Ganglia-general mailing list > > > Ganglia-general@lists.sourceforge.net > > > https://lists.sourceforge.net/lists/listinfo/ganglia-general > > > > -- > /------------------------------------------------------------------\ > | Jason A. Smith Email: [EMAIL PROTECTED] | > | Atlas Computing Facility, Bldg. 510M Phone: (631)344-4226 | > | Brookhaven National Lab, P.O. Box 5000 Fax: (631)344-7616 | > | Upton, NY 11973-5000 | > \------------------------------------------------------------------/ > > > > > ------------------------------------------------------- > This SF.Net email sponsored by Black Hat Briefings & Training. > Attend Black Hat Briefings & Training, Las Vegas July 24-29 - > digital self defense, top technical experts, no vendor > pitches, unmatched networking opportunities. Visit > www.blackhat.com _______________________________________________ > Ganglia-general mailing list > Ganglia-general@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/ganglia-general > >
