Why Does Cloud Load Balancing Suck?
Back in the old world of real infrastructure, we used Netscalers or F5′s and we were happy. Now in the cloud, you have several options all of which seem to have problems.
1. Open source. But once you want SSL, and redundancy, and HTTP compression, you get people saying with a straight face “nginx (for HTTP compression) –> Varnish cache (for caching) –> HTTP level load balancer (HAProxy, or nginx, or the Varnish built-in) –> webservers.” (Quoted from Server Fault). Like four levels, often with the same software twice in it. And don’t forget some kind of heartbeat between the two front-ends. Oh look I’ve spent $150/mo on just machines to run my load balancing. And I really want to load balance/failover between all my tiers not just the front end. It’s a lot of software parts to go wrong.
2. Zeus. For some reason none of the other LB vendors have gotten off their happy asses and delivered a good software load balancer you can use in Amazon. I got tired of talking to our Netscaler reps about it after the first couple years. They’re more interested in selling their hardware to the cloud data centers than helping real people load balance their apps. Zeus is the only one – and it’s really quite expensive
3. Amazon ELBs. These just have a lot of problems under the hood. We’ve been engaged with Amazon ELB product management on them – large files serve out super slow; users get hits refused due to throttling/changes during ELB scaling – basically if you want 100% of your hits to come through you can’t use them.
4. Geo-IP load balancing, through Dyn or whoever. They claim to have the failover problem fixed, but it still only works for the front end tier of what is a multitier architecture. I certainly don’t want to have to advertise every internal IP in external DNS to make load balancing work.
And really the frustrating part is there seems to have been no headway on any of this stuff in a decade. Same old open source options, same old techniques. Can someone come up with a way to load balance on the cloud that a) doesn’t lose any hits, b) is one thing not 4 things, and c) is useful for front and back end balancing? Seems like a necessary part of oh say every system ever, why is it still so hard?
nginx now allows you to have compression, load-balancing, SSL and now cache. Of course, cache functionality is pretty basic compared to varnish and load-balancing functionality is pretty light compared to haproxy.
If only someone would resurrect Resonate! It was a pioneer in the load balancing industry and unfortunately got eaten up by the .com crash. It was software based which meant you can install anywhere and spread the load of your traffic. Also it would allow non-http load balancing for the odd ball apps out there. Maybe need to look at the latest nginx version as its proper successor.
I use Amazon ELB and run the monitoring tool from Pingdom on a 1-minute check. I have yet to have any down time as a result of ELB.
That’s way too low of an interval to find something like the problems I saw. It’s not continuous downtime, it’s 1 in 1000 hits being dropped. Very hard to find.
Has anyone everhad duplicate info transmission due to a load balancing issue?
We had that, not load balancing itself per se but from our network redundancy around our front end, ended up repeating packets on us. I forget what we did about it, mainly yelled at our network admins…
Have you tested Zen Load Balancer? It is still in development, but it can be a very good open source load balancer solution. It is moving with the suggestions of their users, and the develpment team is very active. If you don’t find the features you need, you can suggest it to the mailing list.