After checking that a server or backend is full, it remains possible
to call pendconn_add() just after the last pending requests finishes, so
that there's no more connection on the server for very low maxconn (typ 1),
leaving new ones in queue till the timeout.
The approach depends on where the request was queued, though:
- when queued on a server, we can simply detect that we may dequeue
pending requests and wake them up, it will wake our request and
that's fine. This needs to be done in srv_redispatch_connect() when
the server is set.
- when queued on a backend, it means that all servers are done with
their requests. It means that all servers were full before the
check and all were empty after. In practice this will only concern
configs with less servers than threads. It's where the issue was
first spotted, and it's very hard to reproduce with more than one
server. In this case we need to load-balance again in order to find
a spare server (or even to fail). For this, we call the newly added
dedicated function pendconn_must_try_again() that tells whether or
not a blocked pending request was dequeued and needs to be retried.
This should be backported along with pendconn_must_try_again() to all
stable versions, but with extreme care because over time the queue's
locking evolved.
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| src | ||
| tests | ||
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| CONTRIBUTING | ||
| INSTALL | ||
| LICENSE | ||
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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.
