f1064c7382
Since we made it possible for a bind_conf to listen to multiple thread
groups with shards in 2.8 with commit 9d360604bd ("MEDIUM: listener:
rework thread assignment to consider all groups"), the per-listener
connection count was not properly transferred to the target listener
with the connection when switching to another thread group. This results
in one listener possibly reaching high values and another one possibly
reaching negative values. Usually it's not visible, unless a maxconn is
set on the bind_conf, in which case comparisons will quickly put an end
to the willingness to accept new connections.
This problem only happens when thread groups are enabled, and it seems
very hard to trigger it normally, it only impacts sockets having a single
shard, hence currently the CLI (or any conf with "bind ... shards 1"),
where it can be reproduced with a config having a very low "maxconn" on
the stats socket directive (here, 4), and issuing a few tens of
socat <<< "show activity" in parallel, or sending HTTP connections to a
single-shared listener. Very quickly, haproxy stops accepting connections
and eats CPU in the poller which tries to get its connections accepted.
A BUG_ON(l->nbconn<0) after HA_ATOMIC_DEC() in listener_release() also
helps spotting them better.
Many thanks to Christian Ruppert who once again provided a very accurate
report in GH #2951 with the required data permitting this analysis.
This fix must be backported to 2.8.
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.