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diff --git a/site/src/docs/lighttpd.page b/site/src/docs/lighttpd.page deleted file mode 100644 index 973fd2c..0000000 --- a/site/src/docs/lighttpd.page +++ /dev/null @@ -1,278 +0,0 @@ ---- -title: Lighttpd -inMenu: true -directoryName: Documentation ---- - -*I'm sad to say that I have to recommend people not use lighttpd anymore.* -The author hasn't updated the mod_proxy plugin and isn't providing too much -support for the bugs it has. If you're running lighttpd and you constantly -see 500 errors that are never recovered, then you should switch to Apache -or another web server that can handle properly balancing backends. - - -h1. Using Lighttpd With Mongrel - -It is possible to host an application with just Mongrel since it is -able to serve files like a normal web server. Still, no matter -how fast Mongrel gets it probably can't compete with something -like lighttpd for serving static files. Because of this I've -devised a simple way to setup a lighttpd+Mongrel setup that -demonstrates clustering four Mongrel servers running the same -application as backends. - -This is very similar to a FastCGI or SCGI setup except that -you're just using regular HTTP. Read through the "HOWTO":howto.html -for information on other possible deployment scenarios. - - -h2. The Goal - -What we want to do is put a lighttpd on the internet and then -have it proxy back to one of four Mongrel servers. - -!SimpleLighttpdMongrelSetup.jpg! - -This is actually really trivial and probably doesn't need a diagram -but I got bored just writing it up. - -How it all works is pretty simple: - -# Requests come to the lighttpd server. -# Lighttpd takes each request, and sends it to a backend depending - on how you configure it: - * hash -- Hashes the request URI and makes sure that it goes to the same backend. - * round-robin -- Just chooses another host for each request. - * fair -- "Load based, passive balancing." No idea what that means, but if it's like - the rest of lighttpd it probably means it will overload the first one and if that one's - busy then it starts using the next ones. -# Each backend doesn't really care about any of this since it's just a web server. - - -h2. Lighttpd Configuration - -For lighttpd you need to have *mod_proxy* in your server.modules setting: - - server.modules = ( "mod_rewrite", "mod_redirect", - "mod_access", "mod_accesslog", "mod_compress", - "mod_proxy") - -Then you need to tell lighttpd where the other backends are located: - - proxy.balance = "fair" - proxy.server = ( "/" => - ( ( "host" => "127.0.0.1", "port" => 8001 ), - ( "host" => "127.0.0.1", "port" => 8002 ), - ( "host" => "127.0.0.1", "port" => 8003 ), - ( "host" => "127.0.0.1", "port" => 8004 ) ) ) - -When I used lighttpd 1.4.9 and set proxy.balance="round-robin" I had an excessive number of -500 errors for no real reason. The "fair" setting seems to be the best, but if you -have a large number of fairly random URIs you should try "hash" too. - -*For the rest of this tutorial we'll assume you're running lighttpd on port 80.* - - -h2. Mongrel Configuration - -Mongrel is pretty easy to setup with this configuration on either Win32 or Unix, but -since lighttpd doesn't compile so easily on Win32 I'll just show the Unix method -for starting it: - - $ mongrel_rails start -d -p 8001 \ - -e production -P log/mongrel-1.pid - $ mongrel_rails start -d -p 8002 \ - -e production -P log/mongrel-2.pid - $ mongrel_rails start -d -p 8003 \ - -e production -P log/mongrel-3.pid - $ mongrel_rails start -d -p 8004 \ - -e production -P log/mongrel-4.pid - -Now you should be able to hit your web server at port 80 and it'll run against -one of your four Mongrels. - - -h2. Testing Stability and Performance - -As I mentioned before proxy.balance="round-robin" had many stability issues -in lighttpd 1.4.9 but how did I figure this out? Here's how you can do it. - -You use "httperf":http://www.hpl.hp.com/research/linux/httperf/ to first hit each -Mongrel backend with a large request set. - - $ httperf --port 8001 --server 127.0.0.1 \ - --num-conns 300 --uri /test - $ httperf --port 8002 --server 127.0.0.1 \ - --num-conns 300 --uri /test - $ httperf --port 8003 --server 127.0.0.1 \ - --num-conns 300 --uri /test - $ httperf --port 8004 --server 127.0.0.1 \ - --num-conns 300 --uri /test - -After each of these you're looking for the *Connection rate*, *Request rate*, -*Reply rate*, and *Reply status*. You first look at the *Reply status* to make -sure that you got all 2xx messages. Then look at the other three and make -sure they are about the same. - -Then you hit lighttpd with a similar request set to confirm that it handles the base case. - - $ httperf --port 80 --server 127.0.0.1 \ - --num-conns 300 --uri /test - -You should get no 5xx errors. In the case of round-robin there were about 60% -5xx errors even though the Mongrels were functioning just fine. The "hash" method -didn't improve this test's performance since there's only on URI in the test. It -seems the "fair" method is the best you can do right now. - -Finally you hit lighttpd with a 4x rate to see if it could handle the theoretical limit. - - $ httperf --port 80 --server 127.0.0.1 \ - --num-conns 10000 --uri /test --rate 600 - -It will most likely fail miserably and you'll probably see a few 5xx counts in the -*Reply status* line but that's normal. What you're looking to do is keep moving ---rate and --num-conns up/down until you get where the server is just barely -able to accept the requests without slowing down (i.e. your *Request rate* matches -your --rate setting). There will be a point where adding literally one more -to your --rate setting causes the Request rate to tank. That's your setup's breaking -point and is the actual requests/second you can handle. - - -h1. Insane Caching Power Magnet - -Mongrel (as of 0.3.7) by default supports Rails style page caching -in the RailsHandler it uses to serve your applications. What this -means is that if you do a page cached action (which writes a -.html file as well as respond) then Mongrel will just serve up -the cached page instead of bug Rails. - -This does give you a large boost in performance, but still not nearly -as much as if you had lighttpd doing the caching for you. The optimal -configuration would be where lighttpd checks for cached pages and then -served it directly as it already does with FastCGI. - -There are some technical problems with this and the lighttpd mod_proxy, -but thankfully I don't have to go into them because lighttpd now supports -the "power magnet" and Cache Meta Language (CML). CML is a small bit -of the Lua programming language that lets you script lighttpd and tell -it when to cache or not. The power magnet feature of CML lets you put -all requests through one CML script so that you can determine whether -to cache or not. - -h2. Configuration - -In order to get everything to work right you'll need a few pieces -of equipment and make sure they are enabled in your lighttpd build. -The sample build was done on Debian so that everything would work -including mod_rewrite, mod_memcache, mod_cml, and mod_redirect. - -* lua50, liblua50-dev -* libpcre3-dev -* memcached -* Finally make sure you configure with ./configure --with-lua --with-memcache - -Debian people will need to follow these instructions from -"www.debian-administration.org":http://www.debian-administration.org/articles/20 -for installing from source, and will also need to add these lines to your -/etc/apt/sources.list: - - deb-src http://http.us.debian.org/debian stable main contrib non-free - deb-src http://http.us.debian.org/debian unstable main contrib non-free - deb-src http://non-us.debian.org/debian-non-US stable/non-US main contrib non-free - -And then do the following: - -# Make sure you don't have the source extracted in your current directory. -# apt-get install devscripts debhelper build-essential fakeroot -# apt-get update -# apt-get source lighttpd -# nano -w lighttpd-1.4.10/debian/rules -## DEB_CONFIGURE_EXTRA_FLAGS need have at the end: --with-lua --with-memcache -# nano -w lighttpd-1.4.10/debian/lighttpd.install -## debian/tmp/usr/lib/lighttpd/mod_cml.so needs to be added here. - -Then you're supposed to be able to follow the debian-administration -docs but I haven't got it all working yet. Please clue me in -if you get this compiled on Debian. - -h3. lighttpd.conf - -If it all builds right then you'll be able to use this nifty -CML script that Bradley K. Taylor (from railsmachine.net) came -up with. First you need to tweak your lighttpd.conf at the -place where you have the mod_proxy setup from previous: - - $HTTP["host"] == "www.myhost.come" { - server.document-root = "/my/path/to/app/public" - cml.power-magnet = "/my/path/to/app/config/power-magnet.cml" - proxy.balance = "fair" - proxy.server = ( "/" => ( ( "host" => "127.0.0.1", "port" => 8001 ), - ( "host" => "127.0.0.1", "port" => 8002 ) ) ) - } - -This one just has two for simplicity. The big thing is the -document root setting and the power-magnet.cml setting. I wouldn't -put the power-magnet.cml in your public directory. - -h3. power-magnet.cml - -Now for the magic bit of Lua code that tells lighttpd what to do: - - dr = request["DOCUMENT_ROOT"] - - if file_isreg(dr .. "maintainance.html") then - output_include = { dr .. "maintainance.html" } - return CACHE_HIT - end - - f = request["REQUEST_URI"] - - if f == "/" or f == "" then - file = dr .. "index.html" - elseif not string.find(f, "%.") then -- rewrite for cached pages - file = dr .. f .. ".html" - else - file = dr .. f - end - - if file_isreg(file) then - output_include = { file } - return CACHE_HIT - end - - return 1 -- should be CACHE_MISS, but there's a bug in 1.4.10 - -Place this in the /my/path/to/app/config/power-magnet.cml like you -configured above. - -Now if you restart lighttpd and everything worked right you should -be able to see the headers and tell if Mongrel or lighttpd is serving -them. Use curl like this: - - curl -I http://zedapp.railsmachine.net/ - curl -I http://zedapp.railsmachine.net/admin - -The second one should redirect and show a Mongrel header while the -first one should show a lighttpd header. - - -h2. Memcached - -The next installment of this document will tell you how to setup a -memcached so that you can run the lighttpd on a different server -from the Mongrel cluster. Right now they all have to reside -on one machine. - -h2. CML Tricks - -Since Lua is a full blown and fast little language -you can get pretty creative with it. For example you could -have it check dates and times of files, look for processes -that should be running, run commands, check the contents of -a file, etc. - -Take a look at the "Lua Reference Manual":http://www.lua.org/manual/5.0/ -to see what it can do. Ruby people will probably like Lua. - - - |