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0797e05d9f
We observed that a dynamic server which health check is down for longer than slowstart delay at startup doesn't trigger the warmup phase, it receives full traffic immediately. This has been confirmed by checking haproxy UI, weight is immediately the full one (e.g. 75/75), without any throttle applied. Further tests showed that it was similar if it was in maintenance, and even when entering a down or maintenance state after being up. Another issue is that if the server is down for less time than slowstart, when it comes back up, it briefly has a much higher weight than expected for a slowstart. An easy way to reproduce is to do the following: - Add a server with e.g. a 20s slowstart and a weight of 10 in config file - Put it in maintenance using CLI (set server be1/srv1 state maint) - Wait more than 20s, enable it again (set server be1/srv1 state ready) - Observe UI, weight will show 10/10 immediately. If server was down for less than 20s, you'd briefly see a weight and throttle value that is inconsistent, e.g. 50% throttle value and a weight of 5 if server comes back up after 10s before going back to 6% after a second or two. Code analysis shows that the logic in server_recalc_eweight stops the warmup task by setting server's next state to SRV_ST_RUNNING if it didn't change state for longer than the slowstart duration, regardless of its current state. As a consequence, a server being down or disabled for longer than the slowstart duration will never enter the warmup phase when it will be up again. Regarding the weight when server comes back up, issue is that even if the server is down, we still compute its next weight as if it was up, hence when it comes back up, it can briefly have a much higher weight than expected during slowstart, until the warmup task is called again after last_change is updated. This patch aims to fix both issues.
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)