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haproxy_sticktable_local_updates corresponds to the table->localupdate counter, which is used internally by the peers protocol to identify update messages in order to send and ack them among peers. Here we decide to expose this information, as it is already the case in "show peers" output, because it turns out that this value, which is cumulative and grows in sync with the number of updates triggered on the table due to changes initiated by the current process, can be used to compute the update rate of the table. Computing the update rate of the table (from the process point of view, ie: updates sent by the process and not those received by the process), can be a great load indicator in order to properly scale the infrastructure that is intended to handle the table updates. Note that there is a pitfall, which is that the value will eventually wrap since it is stored using unsigned 32bits integer. Scripts or system making use of this value must take wrapping into account between two readings to properly compute the effective number of updates that were performed between two readings. Also, they must ensure that the "polling" rate between readings is small enough so that the value cannot wrap behind their back.
HAProxy
HAProxy is a free, very fast and reliable reverse-proxy offering high availability, load balancing, and proxying for TCP and HTTP-based applications.
Installation
The INSTALL file describes how to build HAProxy. A list of packages is also available on the wiki.
Getting help
The discourse and the mailing-list are available for questions or configuration assistance. You can also use the slack or IRC channel. Please don't use the issue tracker for these.
The issue tracker is only for bug reports or feature requests.
Documentation
The HAProxy documentation has been split into a number of different files for ease of use. It is available in text format as well as HTML. The wiki is also meant to replace the old architecture guide.
Please refer to the following files depending on what you're looking for:
- INSTALL for instructions on how to build and install HAProxy
- BRANCHES to understand the project's life cycle and what version to use
- LICENSE for the project's license
- CONTRIBUTING for the process to follow to submit contributions
The more detailed documentation is located into the doc/ directory:
- doc/intro.txt for a quick introduction on HAProxy
- doc/configuration.txt for the configuration's reference manual
- doc/lua.txt for the Lua's reference manual
- doc/SPOE.txt for how to use the SPOE engine
- doc/network-namespaces.txt for how to use network namespaces under Linux
- doc/management.txt for the management guide
- doc/regression-testing.txt for how to use the regression testing suite
- doc/peers.txt for the peers protocol reference
- doc/coding-style.txt for how to adopt HAProxy's coding style
- doc/internals for developer-specific documentation (not all up to date)
License
HAProxy is licensed under GPL 2 or any later version, the headers under LGPL 2.1. See the LICENSE file for a more detailed explanation.