HAProxy is a free, very fast and reliable solution offering high availability, load balancing, and proxying for TCP and HTTP-based applications. It is particularly suited for web sites crawling under very high loads while needing persistence or Layer7 processing.

Dec 21, 2017 - In the following tutorial we are going to be demonstrating how you can Install HAProxy HTTP Load Balancer on CentOS, along with more useful information. I've been developing an App for most of the summer. It's using a few backend services so in production I use HAProxy in front of them.

Supporting tens of thousands of connections is clearly realistic with todays hardware. Its mode of operation makes its integration into existing architectures very easy and riskless, while still offering the possibility not to expose fragile web servers to the Net. This post will explain how to install HAProxy on FreeBSD and how to configure it as a simple HTTP load balancer. Getting HAproxy The first step is to download HAProxy. You can find the latest version at this address: As of writing this post, the latest version is 1.3.16, which you can find here: 2. Prepare for installation Log on your FreeBSD machine and change to the temporary directory of your choice.

You can now issue the easy following commands. $ cp haproxy /usr/local/sbin Why? Simply because /usr/local/sbin is usually in $PATH, so haproxy will then be easy to run simply by typing 'haproxy'.

Configuring HAProxy The configuration of HAProxy, like its installation, is really easy. In fact, it can be very easy, or very complex. HAProxy is VERY flexible and it has literally thousands of parameters you can tweak. You can find the whole documentation on the HAProxy official Web site there: As of writing this post, the latest official documentation is there: For this post, we'll keep it simple and configure a simple load balancer.

You can put the HAProxy configuration file where you wish, and name it as you wish! This post will be using this path/filename. Global maxconn 4096 pidfile /var/ run / haproxy. Pid daemon defaults mode http retries 3 option redispatch maxconn 2000 contimeout 5000 clitimeout 50000 srvtimeout 50000 listen GALAXY aaa. Ddd: 80 mode http cookie GALAXY insert balance roundrobin option httpclose option forwardfor stats enable stats auth myuser: mypass server EARTH 192.168.0.2: 8080 cookie GALAXY_SERVER_01 check server MOON 192.168.0.3: 8080 cookie GALAXY_SERVER_02 check >aaa.bbb.ccc.ddd should be the public IP of your server. >192.168.0.2 should be the LAN IP to your server 1.

>192.168.0.3 should be the LAN IP to your server 2. Everything that is in CAPS is customizable.

* GALAXY * EARTH * MOON * GALAXY_SERVER_01 * GALAXY_SERVER_02 Basically, this configuration file is defining a group ('listen' block) called GALAXY, which contains 2 servers: EARTH and MOON. The 'roundrobin' balance option is telling to HAProxy to alternate between the 2 servers all the time.

For the other options in the global, defaults and listen blocks, they're pretty standard. If you need to tweak those or to add options to suit your needs, I'm sure HAProxy can do it!

Simply refer to the whole documentation. Cookie When the user will reach the GALAXY group (using, the cookie GALAXY will be created and the server ID specified for 'cookie' in the servers definitions will be stored in it (GALAXY_SERVER_01 or GALAXY_SERVER_02). Then, for the whole session, HAProxy will read the cookie and force the use of the server stored in it. This behavior is controlled by the 'cookie GALAXY insert' line and the 'cookie GALAXY_SERVER_XX' parts in the GALAXY group block.

If you don't want this feature, simply remove or comment (using a '#') these parts. Stats There's a pretty complete load balancer stats page built-in HAProxy. Universal Beam Autocad Blocks Furniture. You can reach it there: With the configuration above, the username will be 'myuser' and the password 'mypass'. If you don't want the stats to be enabled, you can simply remove or comment these lines. One great things about HAProxy is that it supports several load-balancing algorithms: * Simple round robin (traffic divided equally) * Least connections (server with least connections gets the request) and our favorite - * Source (The source IP address is hashed and divided by the total weight of the running servers to designate which server will receive the request) The source algorithm ensures that the same client IP address will always reach the same server as long as no server goes down or up.

Very important when using HAProxy to load balance databases and avoid replication latencies. When using HAProxy to load-balance Java Lucene servers, we noticed an interesting problem - Java File Handlers were leaking. On every single 'hit' from HAProxy to check the status of the Java server, about 10 descriptors leaked and were never released by the garbage collector. We even tried invoking the garbage collector with.gc() but nothing worked.