perlbal::manual::highpriority(3pm) [debian man page]
Perlbal::Manual::HighPriority(3pm) User Contributed Perl Documentation Perlbal::Manual::HighPriority(3pm) NAME
Perlbal::Manual::HighPriority - Perlbal's high/low priority queueing system. VERSION Perlbal 1.78. DESCRIPTION This document describes Perlbal's high/low priority queueing system. Queuing system Perlbal has three queues: normal, high priority and low priority. As their names suggest, this means that usually requests get to the normal queue and are dispatched in FIFO order, with high priority requests going to a different queue that gets ahead of the normal one and a low priority queue that only gets done when the high and normal queues are empty. In a nutshell, whenever Perlbal needs to select which request to take care of next, it first looks for requests in the high priority queue; if that one is empty, it then looks into the normal queue; and, if the normal queue is empty too, it finally looks in the low priority queue. High priority with cookies Perlbal can use cookies to determine if a request should go to the high priority queue (configurable). The parameters to configure this are "high_priority_cookie" and "high_priority_cookie_contents"; the first defines the name of the field to check for on the cookie and the second one defines the content in that field that will trigger the request going to the fast queue: SET myservice.high_priority_cookie = name_of_the_field SET myservice.high_priority_cookie_contents = required_content_on_that_field Here's a clearer example: SET myservice.high_priority_cookie = highpriority SET myservice.high_priority_cookie_contents = yes High priority with plugins The plugin Perlbal::Plugin::Highpri supports making requests high priority by URI or Host. Also check "make_high_priority" under Perlbal::Manual::Hooks. Queue relief Sometimes if the high priority queue is really busy, the standard queue will suffer from resource starvation. The queue relief system helps prevent this. When there are "queue_relief_size" or more connections in the standard queue, newly available backends have a "queue_relief_chance" percent chance of taking a request from the standard priority queue instead of the high priority queue. SET web_proxy.queue_relief_size = 2000 SET web_proxy.queue_relief_chance = 30 # 0-100, in percent SEE ALSO "make_high_priority" and "make_low_priority" in Perlbal::Manual::Hooks, Perlbal::Plugin::HighPriority. perl v5.14.2 2011-01-23 Perlbal::Manual::HighPriority(3pm)
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Perlbal::Manual::WebServer(3pm) User Contributed Perl Documentation Perlbal::Manual::WebServer(3pm) NAME
Perlbal::Manual::WebServer - Configuring Perlbal as a Web Server VERSION Perlbal 1.78. DESCRIPTION How to configure a Perlbal Web Server service. READ ME FIRST Please read Perlbal::Manual::Configuration first for a better explanation on how to configure Perlbal. This document will make much more sense after reading that. Configuring Perlbal as a Web Server By default, perlbal looks for a configuration file at /etc/perlbal/perlbal.conf. You can also point perlbal at a different configuration file with the -c flag. $ perlbal -c /home/user/perlbal.conf Here's a very simple example where we configure a simple web server that serves an index file under /tmp CREATE SERVICE perlbal_test SET role = web_server SET listen = 0.0.0.0:80 SET docroot = /tmp ENABLE perlbal_test The first line creates a service called "perlbal_test". The last line enables that service. The three parameters state - in order - that the service is a web server, that it listens on all addresses on port 80, and that its document root is "/tmp". Parameters You can set parameters via commands of either forms: SET <service-name> <param> = <value> SET <param> = <value> dirindexing = bool Show directory indexes when an HTTP request is for a directory. Warning: this is not an async operation, so will slow down Perlbal on heavily loaded sites. Default if false. docroot = directory/root Directory root for web server. enable_concatenate_get = bool Enable Perlbal's multiple-files-in-one-request mode, where a client have use a comma-separated list of files to return, always in text/plain. Useful for web apps which have dozens/hundreds of tiny css/js files, and don't trust browsers/etc to do pipelining. Decreases overall round-trip latency a bunch, but requires app to be modified to support it. See t/17-concat.t test for details. Default is false. enable_md5 = bool Enable verification of the Content-MD5 header in HTTP PUT requests. Default is true. enable_delete = bool Enable HTTP DELETE requests. Default is false. enable_put = bool Enable HTTP PUT requests. Default is false. index_files = comma-separated list of filenames Comma-separated list of filenames to load when a user visits a directory URL, listed in order of preference. Default is index.html. max_put_size = size The maximum content-length that will be accepted for a PUT request, if enable_put is on. Default is 0, which means there is no limit. min_put_directory = int If PUT requests are enabled, require this many levels of directories to already exist. If not, fail. Default is 0. server_tokens = bool Whether to provide a "Server" header. Perlbal by default adds a header to all replies (such as the web_server role). By setting this default to "off", you can prevent Perlbal from identifying itself. Default is "on". SEE ALSO Perlbal::Manual::Configuration, Perlbal::Manual::Management. perl v5.14.2 2012-02-20 Perlbal::Manual::WebServer(3pm)