On Thu, 2014-08-14 at 17:48 +0000, Jake Zack wrote: > Anyone doing this? > > > > Previously I’d been using Cisco 3945’s and 3845’s running standard > IOS…thus using Cisco IP SLA + track to do DNS queries of each server > and add/remove them from the cluster. > > > > In the ASR 9xxx series with IOS XR, the “ipsla” that it has available > doesn’t seem to do either TCP connections or UDP DNS queries. It > seems my only real option is to monitor for ICMP reachability and > nothing else. > > > > Anyone have a better solution? I’ve considered throwing a wrapper > around BIND doing OSPF updates and such…but it seems unideal. > > > > -Jake > > DNS Administrator – CIRA (.CA TLD) > >
We are using a couple of small clusters of Linux Servers (Scientific linux (whitebox RHEL distribution) for recursive resolvers. They consist of 2 load balancers using a CMAN/Pacemaker cluster. The load balancing is done with the Linux kernel's IP Virtual SErvice (IPVS) featire. The resolver IPs are VIPs managed by the cluster. And the load balancers are setup to replication their connection tables to each other to add in seamless failover capabilities Also in the mix I run keepalived on the load balancers. Keepalived manages the IPVS configuration in conjunction with health checks for each of the back-end nodes. If a back-end node stop responding, the IPVS configuration is altered to remove that node from tthe cluster. And note that keepalived also implements a VRRP routing daemon for failover between a set of routers. (We don't use VRRP in our setup.) There are 4 back-end servers running just Bind as caching name servers with a few of our main authoritative zones as slaves. The load balancers have all of the back-end servers in their configurations, but we normally only have 2 back-end nodes servicing one of the resolver VIPs. The other two are set to weight 0. I can alter the weights in the lod balancers to bring back-end nodes in and out of service and to move them between resolver VIPs. I've clocked a resolver cluster (1 Load Balancers, 2 backend nodes and named caches flushed) north of 11,000 queries per second before it queries started to fail. I've been using a similar setup (minus the keepalived) for well over 7 years with out any major issues. The resolvers clusters have been running about 3 years without any major issues. -- Stephen L Johnson <[email protected]> Unix Systems Administrator / DNS Hostmaster Department of Information Systems State of Arkansas 501-682-4339 _______________________________________________ dns-operations mailing list [email protected] https://lists.dns-oarc.net/mailman/listinfo/dns-operations dns-jobs mailing list https://lists.dns-oarc.net/mailman/listinfo/dns-jobs
