Per-Entity Metadata Working Group

[Nick Roy <>]

On 9/14/16 2:31 PM, Cantor, Scott wrote:
> On 9/14/16, 3:58 PM, 
> "
>  on behalf of Nick Roy" 
> <
>  on behalf of 
> >
>  wrote:
>
> >     I'll also just leave this here for you to peruse/think about:
> >     
> > https://loadbalancer.org/blog/gslb-why-do-global-server-load-balancers-suck
> There are lot of those articles around, many of which I've read very 
> recently, and they all share some characteristics:
>
> - they're years old, sometimes 10+
> - they don't actually offer a solution to the problems
>
> When state isn't a consideration, I would agree that certainly one has more options, 
> and it's probably easier to manipulate DNS or just make clients a little smarter, and 
> you'll end up most of the way there anyway. And if that's how people serve content now, 
> that's fine, though of course they're doing so on the backs of browsers having been 
> forced to do an absolute ton of changes to handle DNS and failover differently than 
> they did in 1995. In other words "GSLB sucks if you can make Firefox do it all for 
> you". Well, we're not Firefox unfortunately.

I thought I remembered you saying that you were going to have to make 
changes to Shibboleth client software to achieve the kinds of uptime 
goals you were hoping for when we started researching CDN 
characteristics.  What happened to that line of thinking?

Nick

> Speaking more generally, if you add sticky state (and this doesn't apply to 
> MDQ, I'm talking in general), suddenly all these tricks fail horribly, and 
> you either do GSLB, hack your own GSLB (could be as simple as hot/cold of 
> course), or you just hope you never have a network outage I guess.
>
> The modern GSLB devices really do the crazy things you thought you'd have to 
> make them do to pull it off, because they had to do something to justify the 
> prices. They proxy each other in real time behind the scenes to prevent 
> client addresss switches from breaking apps. Jim Fox described doing that 
> himself with cookies + Apache many years back. It is basically the only way 
> to avoid a real-time SPOF from your network layer.
>
> Do they work? I'm probably going to find out soon and will certainly let you 
> know. If they don't, then there really isn't much I can do about it, so 
> hot/cold it is.
>
> -- Scott