Steven Dake napsal(a): > Hi, > > Speaking with Angus who spoke with Andrew about the problem of getting > Corosync to run inside cloud guests, specially OpenStack, spawned this > conversation... > > Currently the problem is that with UDPU mode and a bindnetaddr set, the > interface binding code first searches for the ip address, then once > found, determines the interface which that ip address is connected to. > > This would work great if cloud guests had static ip addresses which they > are assigned, but in most cases this is not the case. IP addresses are > assigned dynamically from an address pool. This means on restart, > without detailed knowledge of the cloud deployment, it is not possible > to set a bindnetaddr up that works consistently. Further complicating > matters is that the target node list IP addresses change in the > non-floating-ip model. > > One simple solution is to use the following config model: > 1. obtain a floating ip address from OpenStack > 2. configure the guest vms with the floating IPs > 3. hold floating IP for lifetime of application > > The way floating IPs work (atleast in OpenStack) is that they create > iptables on the host to represent the ip address. As a result, using > floating IPs with the current totemip behavior doesn't solve the problem > because totemip will still desire to bind to a specific address. > Unfortunately the floating IPs don't present a physical interface inside > the guest VM, but are handled externally by iptables. This makes > binding impossible. > > One solution to this problem is to add a new mode "inaddr_any" for > bindnetaddr. Then when corosync starts, it will bind to INADDR_ANY > interface and the udpu traffic will be routed properly by iptables. > I've found following problems with your solution: - Corosync is inserting bind IP address (system_from filed) of all rings to every packet. So it's needed to know WHAT IP address is in use. How we will find it with inaddr_any? (Ignoring fact that this field may be ignored because it should be used in multiring which is not implemented) - Because we don't know IP addresses, how we will fill udpu members list? How will corosync know what are other nodes to contact them? > Any thoughts on a simpler solution or on this solution? > Actually I believe only way to achieve correct functionality will be much harder solution of proper OpenStack integration... Hopefully I'm wrong in there. > Regards > -steve Regards, Honza _______________________________________________ discuss mailing list discuss@xxxxxxxxxxxx http://lists.corosync.org/mailman/listinfo/discuss
