On 05/11/15 22:10, Christopher Schultz wrote:
> I would argue that any production deployment ought to utilize a load
> balancer and at least two servers, even if only to allow you to take one
> of them offline for upgrades. Maybe you don't require 24x7 uptime, but
> most production deployments do, and having a single box running
> everything is simply not robust enough.
>
> Note that "load balancer" can be any number of things, including an
> industrial-strength piece of hardware to a simple httpd instance (which
> has its own set of similar uptime issues).
>
> -chris
>
>
I agree. I mentioned ip-address fail-over to independent tomcats as a
possibility but we certainly think things are more robust with a load
balancer in the picture. In production we use ucarp for load-balancer
resilience not tomcat.
We have 4 independent hardware infrastructures each in a different
machine room including one off-site. There are seperate VLANs for public
and internal network traffic.
We use an apache http as the load balancer and to serve static content.
Each infrastructure has its own apache instance but only one is handling
traffic at a time (public ip address switched by ucarp)
Each infrastructure also runs tomcat instances, accessible by any of the
load-balancers.
and database servers (galera cluster) again accessible from any of the
tomcat instances.
>From a tomcat point of view this is pretty standard. We use the ucarp
trick to introduce redundancy in the load balancers themselves.
We wanted a solution that let us do full power-downs in any machine room
or even for an entire datacenter so we went with a redundant physically
distributed load-balancer.
This seems to work pretty well for us, its not 100% (nothing ever is)
but its pretty good. Its also nice that is a pure software solution
(open software at that) we could do a rolling replacement of the whole
hardware infrastructure if we wanted.
What approached do other people use to add redundancy to their
load-balancers?
Stephen
======================================================================
|epcc| Dr Stephen P Booth Principal Architect |epcc|
|epcc| s.bo...@ed.ac.uk Phone 0131 650 5746 |epcc|
======================================================================
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