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It is possible to loose the request after several L7 retries, leading to crashes, because the request channel flag stating some data were sent is not properly reset. When a L7 retry is performed, some flags on different entities must be reset to be sure a new connection will be properly retried, just like it was the first one, mainly because there was no connection establishment failure. One of them, on the request channel, is not reset. The flag stating some data were already sent. It is annoying because this flag is used during the connection establishment to know if an error is triggered at the connection level or at the data level. In the last case, the error must be handled by the HTTP response analyzer, to eventually perform another L7 retry. Because CF_WROTE_DATA flag is not removed when a L7 retry is performed, a subsequent connection establishment error may be handled as a L7 error while in fact the request was never sent. It also means the request was never saved in the buffer used to performed L7 retries. Thus, on the next L7 retires, the request is just lost. This forecefully leads to a bunch of undefined behavior. One of them is a crash, when the request is used to perform the load-balancing. This patch should fix issue #2793. It must be backported to all stable versions.
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.