We have multicast enabled on the switch. I've also tried the multicast.py tool from RH's knowledge base to test multicast and I see the expected output, though the tool uses a different multicast IP( guess that shouldn't matter). I've tried increasing the post_join_delay to 360 seconds to give me enough time to check everything on both the nodes. One node still gets fenced. `clustat` output says the other node is offline on both servers. So one node can't see the other one ? This again points to issue with multicast. Any other clues as to what/where to look ?
On Wed, Jun 11, 2014 at 8:33 PM, Digimer <li...@alteeve.ca> wrote: > On 11/06/14 10:48 AM, Arun G Nair wrote: > >> Hello, >> >> What are the reasons for fence loops when only cman is started ? We >> have an RHEL 6.5 2-node cluster which goes in to a fence loop and every >> time we start cman on both nodes. Either one fences the other. Multicast >> seems to be working properly. My understanding is that without rgmanager >> running there won't be a multicast group subscription ? I don't see the >> multicast address in 'netstat -g' unless rgmanager is running. I've >> tried to increase the fence post_join_delay but one of the nodes still >> gets fenced. >> >> The cluster works fine if we use unicast UDP. >> >> Thanks, >> > > Hi, > > When cman starts, it waits post_join_delay seconds for the peer to > connect. If, after that time expires (6 seconds by default, iirc), it gives > up and calls a fence against the peer to put it into a known state. > > Corosync is what determines membership, and it is started by cman. The > rgmanager only handles resource start/stop/relocate/recovery and has > nothing to do with fencing directly. Corosync is what uses multicast. > > So as you seem to have already surmised, multicast is probably not > working in your environment. Have you enabled multicast traffic on the > firewall? Do your switches support multicast properly? > > digimer > > -- > Digimer > Papers and Projects: https://alteeve.ca/w/ > What if the cure for cancer is trapped in the mind of a person without > access to education? > > -- > Linux-cluster mailing list > Linux-cluster@redhat.com > https://www.redhat.com/mailman/listinfo/linux-cluster > -- Arun G Nair Sr. Sysadmin Dimension Data | Ph: (800) 664-9973 Feedback? We're listening <http://www.surveymonkey.com/s/XRCYXBH>
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