585ece4c92
This is the last patch of the shm stats file series, in this patch we implement the logic to store and fetch shm stats objects and associate them to existing shared counters on the current process. Shm objects are stored in the same memory location as the shm stats file header. In fact they are stored right after it. All objects (struct shm_stats_file_object) have the same size (no matter their type), which allows for easy object traversal without having to check the object's type, and could permit the use of external tools to scan the SHM in the future. Each object stores a guid (of GUID_MAX_LEN+1 size) and tgid which allows to match corresponding shared counters indexes. Also, as stated before, each object stores the list of users making use of it. Objects are never released (the map can only grow), but unused objects (when no more users or active users are found in objects->users), the object is automatically recycled. Also, each object stores its type which defines how the object generic data member should be handled. Upon startup (or reload), haproxy first tries to scan existing shm to find objects that could be associated to frontends, backends, listeners or servers in the current config based on GUID. For associations that couldn't be made, haproxy will automatically create missing objects in the SHM during late startup. When haproxy matches with an existing object, it means the counter from an older process is preserved in the new process, so multiple processes temporarily share the same counter for as long as required for older processes to eventually exit.
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.