In this patch, the update tree is replaced by a mt-list. It is a huge patch with several changes. Main ones are in the function sending updates. By using a list instead of a tree, we loose the order between updates and the ability to restart for a given update using its id (the key to index updates in the tree). However, to use the tree, it had to be locked and it was a cause of contention between threads, leading the watchdog to kill the process in worst cases. Because the idea it to split the updates by buckets to divide the contention on updated, the order between updates will be lost anyway. So, the tree can be replaced by a list. By using a mt-list, we can also remove the update lock. To be able to use a list instead of a tree, each peer must save its position in the list, to be able to process new entries only at each loop. These marker are "special" sticky session of type STKSESS_UPDT_MARKER. Of course, these marker are not in any stick-tables but only in updates lists. And only the ownr of a marker can move it in the list. Each peer owns two markers for each list (so two markers per shared table). The first one used a start point for a loop, and the other one used as stop point. The way these marker are moved in the list is not obvious, especially for the first one. Updates sent during a full resync are now handled exactly a the same way than other updates. Only the moment the stop marker is set is different.
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.
