The `failover` and `failover_timeout` parameters are now declared as a
part of the mysqlmon module. Changed the implementation of the failover
function so that the dependencies on the monitor struct can be removed or
moved into parameters.
The failover command is simulated by executing a call to /usr/bin/echo
with all possible monitor parameters. This allows testing of the failover
mechanism without actually using the failover command.
The timestamp of the last change from passive to active is now
tracked. This, with the timestamps of the last master_down and master_up
events, allows detection of cases when MaxScale was failed over but the
failover was not done.
Currently, only a warning is logged if no new master has appeared within
90 seconds of a master_down event and MaxScale was set to active from
passive.
The last event and when the event was triggered is now shown for all
servers. The latest change from passive to active is also shown.
The monitors should only be reused if they have the same name and they use
the same module. This way the only difference is in configuration.
Fixed MaxCtrl detection of bad options and altered monitor creation test
to expect correct results. Also improved some of the error messages.
If a destroyed monitor is created again, it will be reused. This should
prevent excessive memory growth when the same monitor is created and
destroyed again.
When a persisted configuration file is read, the values in it are
considered to be more up-to-date than the ones in the main configuration
file. This allows all objects to be persisted in a more complete form
making it easier to change configuration values at runtime.
This change is intended to help make runtime alterations to services
possible.
Monitor resources can now be altered with a PUT request. The method allows
alterations on all parameters that the maxadmin `alter monitor` command
allows.
This number (defaults to 1) sets how many times mon_connect_to_db
will try to connect to a backend before returning an error. Every
connection attempt may take backend_connect_timeout seconds to
complete.
Also refactored code a bit. Renamed mon_connect_to_db to
mon_ping_or_connect_to_db, since it does not connect if the connection
is already alive.
Moved some typedefs to router.h and server.h, changed a few
constants to these enums. Renamed some types in config.h to
remove "Gateway".
There are still some functions in the public header which are
only used in core, but they seem to fit the theme of public functions
so were not moved.
When the relay master or external slave states change, they should be
ignored in the current implementation. When the relay master and slave of
external master events are added, the events can be enabled.
