On Thu, Mar 27, 2014 at 04:47:15PM +0100, basti wrote: > Hello, > perhaps that's a bit off topic here but can someone explain what I need > to build a hardware failover nginx cluster? > > The unclear is: > How does the client know that the server 1 is down and use the other one? > DNS failover has a delay because of the design I think. > > client ---> SRV1 > |---> SRV2 (failover if SRV1 is down and load balancing) > > how did it work on google or somethink else?
Here's what you need to do a failover cluster: - two or more sets of hardware - individual addresses for each machine - a shared address that both will answer to when needed - a system for sharing needed resources - a system for choosing which hardware will answer the shared address DNS has two methods for providing alternate resources: you can use a RR (round robin), in which case one name will be resolved into several IPs, and the client may or may not choose appropriately; or you can use a short TTL and update the A or CNAME record to match your desired server. Neither of those methods is much good, and in practice they are only used as the first stage of a more complicated load balancing system. Please read up on corosync, pacemaker and wackamole. -dsr- -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: https://lists.debian.org/20140327164623.gp25...@randomstring.org
