mirror of
https://git.haproxy.org/git/haproxy.git/
synced 2025-09-22 22:31:28 +02:00
13a9232ebc
Most DNS servers provide A/AAAA records in the Additional section of a response, which correspond to the SRV records from the Answer section: ;; QUESTION SECTION: ;_http._tcp.be1.domain.tld. IN SRV ;; ANSWER SECTION: _http._tcp.be1.domain.tld. 3600 IN SRV 5 500 80 A1.domain.tld. _http._tcp.be1.domain.tld. 3600 IN SRV 5 500 80 A8.domain.tld. _http._tcp.be1.domain.tld. 3600 IN SRV 5 500 80 A5.domain.tld. _http._tcp.be1.domain.tld. 3600 IN SRV 5 500 80 A6.domain.tld. _http._tcp.be1.domain.tld. 3600 IN SRV 5 500 80 A4.domain.tld. _http._tcp.be1.domain.tld. 3600 IN SRV 5 500 80 A3.domain.tld. _http._tcp.be1.domain.tld. 3600 IN SRV 5 500 80 A2.domain.tld. _http._tcp.be1.domain.tld. 3600 IN SRV 5 500 80 A7.domain.tld. ;; ADDITIONAL SECTION: A1.domain.tld. 3600 IN A 192.168.0.1 A8.domain.tld. 3600 IN A 192.168.0.8 A5.domain.tld. 3600 IN A 192.168.0.5 A6.domain.tld. 3600 IN A 192.168.0.6 A4.domain.tld. 3600 IN A 192.168.0.4 A3.domain.tld. 3600 IN A 192.168.0.3 A2.domain.tld. 3600 IN A 192.168.0.2 A7.domain.tld. 3600 IN A 192.168.0.7 SRV record support was introduced in HAProxy 1.8 and the first design did not take into account the records from the Additional section. Instead, a new resolution is associated to each server with its relevant FQDN. This behavior generates a lot of DNS requests (1 SRV + 1 per server associated). This patch aims at fixing this by: - when a DNS response is validated, we associate A/AAAA records to relevant SRV ones - set a flag on associated servers to prevent them from running a DNS resolution for said FADN - update server IP address with information found in the Additional section If no relevant record can be found in the Additional section, then HAProxy will failback to running a dedicated resolution for this server, as it used to do. This behavior is the one described in RFC 2782.
The HAProxy documentation has been split into a number of different files for ease of use. 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)