[Pacemaker] Best setup for lots and lots of IPs

Anton Melser melser.anton at gmail.com
Thu Jan 19 14:49:46 EST 2012

I want to set up a very simple NAT device for natting around 2000
internal /24 networks to around 2000 external IPs (1 /24 = 1 public
IP). That part works fine (and is *extremely* efficient, I have it on
a pretty powerful machine but cpu is 0% with 2gbps going through!)
with iproute2 and iptables. I want it to have some failover though...
I am discovering everything here (including iproute2 and iptables),
and someone suggested I look at corosync + pacemaker. I did the
tutorial (btw if I end up using this I'll translate it into French if
you would like) and things seemed to work fine for a few IPs...
However, my

crm configure primitive ClusterIP.ABC ocf:heartbeat:IPaddr2 params
ip=10.A.B.C cidr_netmask=32 op monitor interval=120s

commands started to slow down around 200 IPs and then to a crawl at
500-600 or so. It got to around 1000 before I stopped the VMs I was
testing on to move them onto a much more powerful VM host. It is
taking an absolute age to get back up again. This may be normal, and
there may be no way around it with any decent solution - I simply have
no idea.
Am I trying to achieve something with the wrong tools here? I don't
need any sort of connection tracking or anything - we can handle up to
even maybe 5 minutes of downtime (as long as it's not regularly
happening). The need is relatively simple but the numbers of
networks/IPs may make this unwieldy using these tools.
Any pointers?
Thanks heaps,

echo '16i[q]sa[ln0=aln100%Pln100/snlbx]sbA0D4D465452snlbxq' | dc
This will help you for 99.9% of your problems ...

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