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Load Balancers for Linux?
scales asks: "We currently use the Dispatcher component of IBM's WebSphere Edge Server as a load balancer on some Red Hat boxes where I work, and the boss has asked me to look into OSS alternatives. I've already been pointed at Linux Virtual Server and Ultra Monkey, and I was wondering if any readers have had any experience with these packages, or had any opinions they could offer about other products." Ask Slashdot last visited a similar topic way back in 1999, so I think it might be time for an update.
Mosix will migrate processes. How does that load balance 12 apache servers?
Mosix is good for CPU intensive batch number crunching using custom software. (no shared memory, no threads, smart use of IO and sockets, etc.). Don't get me wron. I think it is very cool, just not a load balancer the way most people use the term "load balancing".
Joe
Joe Batt Solid Design
I hear that the Wai Wai Tribe Is pretty good at balancing large loads.
(ok. that was retarded, but someone had to say it)
HURD - Hurd's Under Research & Development
I used UltraMonkey way back a few years ago.. It did the job.. and we never went down.. it has i believe 4 ways you can weight the webservers.... Actually.. it does more than just webservers... which is a plus as well...
I liked..
ChiefArcher
If so look at JBoss's load balancing.
If you just want it for Web server there is an Apache module for load balancing as well.
Open Source Identity Management: FreeIPA.org
i havnt used it, but, isnt this what your looking for... http://www.backhand.org/mod_backhand/ anyone here used it? did it leave your days filled with joy and happyness or dispair and bitterness?
no sig today, come back tomorrow
I'm confused. Is there some reason why this job can't best be done with a content balancer? It's been about a year since I looked at them, but last I recall Cisco's Local Directors were very highly regarded. They had intelligent session-level balancing and such, and worked well.
I write in my journal
No matter what anyone else here says...
That's rather disingenuous of you, actually, to basically assume that your thoughts on this subject should take precident before all others. In response, I would say that there are many more avenues for support in an OSS solution than would exist with a proprietary application.
1) groups.google.com is an infinitely valuable resource.
2) The Linux Documentation Project maintains a searchable list of man pages, HOWTOs and other documentation.
3) Just about every OSS application in existence maintains mailing lists for developers and users alike for you to be able to receive and provide support for that particular application.
4) There are many consulting companies and individuals out there that provide support on an as-needed basis should you be unable to find your answer elsewhere.
The fact remains, that with an OSS solution, many more people (including developers on the project) are likely to have a better understanding of the application that are willing and able to provide knowledgable support just because of its openness, if that's, indeed, what you want. You may not actually be able to use the phone, but instead, you can send an email to a group of people that are actually passionate about the application, instead of trying to get help from poeple who either don't care, can't understand the application as well as the designers, or who are there to get their $10/hour for a few hours before they go home to finish their homework. When my boss is breathing down my neck about a problem, I'd much rather let him know I'm discussing the issue with one of the guys that designed the application rather than a highschool kid that reads a script to meet his inbound call quota.
That's terrible advice. Do you really want to to be on the phone with a Level I tech while your entire website is down? If a service is truly critical to you, and you're basing your decision on the speed of support, you've done something wrong in the design of your network.
A much better solution would be to make everything redundant and failover automatically.
- James
http://www.redhat.com/software/advancedserver/tech nical/piranha.html
Why aren't we told when editors moderate our posts?
LVS was able to handle a medium-sized HTTP/HTTPS load at my last job quite well. It had 6 months of uptime serving 5-10 hits/second, and I literally never had to worry about it going down. In combination with mon, bringing machines up and down was never a problem, and failure situations were handled without the end user noticing.
Installation was a bit frustrating because I hadn't dealt with the networking issues before (the ARP problem). However, in the end it was only my lack of networking knowledge that was lacking, and the ARP problem turned out to be simple to overcome.
Support from the mailing list was great, I got thorough replies to my questions in a few hours. The documentation is good, although some parts of the HOWTO could be trimmed back a bit (more information than is needed to understand the problem, takes a bit of time to filter).
The hardware was two slower UP boxes (one live, one for failover), and the load was esstentially 0, even with mon and MRTG running.
LVS is of course just the load balancer, and the setup also included mon for monitoring, heartbeat for failover, and MRTG for trending. They all play well together, and create a very reliable, informative, load balancer setup.
Depending on your setup, one of the meta-packages such as Ultra Money or Redhat's HA suite might be best, but installing the components individually isn't much of a hassle either.
1> that is great, I am sure you can find support there for almost anything. Including stuff that has support for non OSS projects.
2> That is great what if it is not in the "HOWTO's?". Last time I checked I did not see a HOWTO: What do do when your OSS load balancer goes down and they don't have any support. This is a blanket answer that assumes that what ever he gets has a howto. It also assumes that I can wait on e-mail. Or search for help or anything else under the sun that takes time. I don't want to be in this possition to have to go find help, I want to know it is there. Where, when, and my call...OSS programers/hackers/anything unless you find the right group that is getting paid is not this.
3> Ahhh...ok that is great. You know this personally that every one of them lists the developers? I can call them? I can e-mail them and expect a response quickly? NO you say? mabye...I don't think I want to wait someones e-mail response on the future of my company. Sorry that just does not cut it.
4> Ok now we are getting someplace. This is called support, which is what I said you need to check into. Glad that you agree.
That last statement is an assumption. Period. You don't know that the guy the wrote the OSS is not a high school kid. Not that it even matters. What happends when someone tells you they don't know.
Your telling me that if I had websphere, cisco, or microsoft that you can HONESTLY that a business can get the same support from people for free you can from paying someone? No you can't not for all of them, not for even 10% of them. So I said make sure you have support....find the one that falls in the 10%, buy a product with support at the ready. I did not say "don't get OSS". I said get something with support, your the one the jumped at "OSS does not have support". Why is that?
I don't have time to wait for and e-mail, or a programmer to come back from snowboarding...or whatever when a 4million hit a day e-com site goes down. Sorry, you just can't play in that league without some security around your hardware, software, and everything else. Which your average everyday OSS project just does not have. Sorry if I got your nickers in a twist. Just the way it is.
Neck_of_the_Woods
#/usr/local/surf/glassy/overhead
I'd have to agree with this. Having used one of the big names in load balancing and having dealt with their support, my experience is that they are not quick and they are not responsive and my project is slipping because they don't understand their product well enough.
The problem with support is that you assume because you are paying a lot of money to the company who created the product that whomever you contact in that organisation knows the product inside out and can answer your problem instaneously.
The truth of the matter is that they are unlikely to understand you environment, and are likely to waste the first 30 minutes going through a set of basic questions which you have already tried anyway. It is a fallacy that telephone support is quicker because you are dependant on the skill and experience of the person you are calling. More specifically you are dependant on their skill and experience with the particular product you are calling about (no one is an expert on everything) and you are then subsequently dependant on the knowledge of other team members in the same room or the quality of the knowledge base that the support engineer is typing your problem into.
If you ever had to ring up support for the worlds number one database vendor you would recognise this situation as they tell you they are typing your details into the system to see how other people with the same problem resolved it.
It won't give your manager the same warm feeling of comfort but OSS and Google is just quicker and easier to support. As long as you choose a well supported project.
The Romans didn't find algebra very challenging, because X was always 10
It doesn't make very much sense to say "Should I use UltraMonkey or LVS?" as the latter is a piece of the former. There are other combinations of LVS+other stuff that you might put into that sentence: "Should I use Piranha or UltraMonkey?" or "Should I use UltraMonkey or Joe Macks LVS Config scripts?" or even "Should I build my own LVS scripts or use an existing framework?"
There are other HTTP load balancing options out there. Squid has a new branch in CVS called rproxy that handles multiple backend web servers very effectively with failure detection and other fun stuff (not to mention caching). Pound is a reverse proxy that does load balancing of HTTP traffic and SSL wrapping (most everything Squid can do for reverse proxying minus the caching features).
Balance is a generic TCP load balancer with some nice features. The best features being that it is simple and works on more platforms than just Linux and handles more than just the HTTP protocol. It probably has some disadvantages for some situations because it operates at a lower level than the HTTP proxies above, though it can probably do lots of the same things LVS does (I don't know very much about Balance).
Eddie is a neat framework written in Ericssons Erlang language. Seems to be dormant, but I think it is in pretty widespread use so is probably pretty stable.
Links:
LVS
Squid rproxy branch
Pound
Balance
Eddie