After giving it some thought, it could pretty well happen that other
protocols benefit from the sticky algorithm that some used to emulate
using a "stick-on int(0)" or things like this previously. So better
rename it to "sticky" right now instead of having to keep that "log-"
prefix forever. It's still limited to logs, of course, only the algo
is renamed in the config.
"log-balance" directive was recently introduced to configure the
balancing algorithm to use when in a log backend. However, it is
confusing and it causes issues when used in default section.
In this patch, we take another approach: first we remove the
"log-balance" directive, and instead we rely on existing "balance"
directive to configure log load balancing in log backend.
Some algorithms such as roundrobin can be used as-is in a log backend,
and for log-only algorithms, they are implemented as "log-$name" inside
the "backend" directive.
The documentation was updated accordingly.
This regtest declares and uses 3 log backends, one of which has TCP syslog
servers declared in it and other ones UDP syslog servers.
Some tests aims at testing log distribution reliability by leveraging the
log-balance hash algorithm with a key extracted from the request URL, and
the dummy vtest syslog servers ensure that messages are sent to the
correct endpoint. Overall this regtest covers essential parts of the log
message distribution and log-balancing logic involved with log backends.
It also leverages the log-forward section to perform the TCP->UDP
translation required to test UDP endpoints since vtest syslog servers
work in UDP mode.
Finally, we have some tests to ensure that the server queuing/dequeuing
and failover (backup) logics work properly.
Willy Tarreau
Aurelien DARRAGON