The cluster check can only be made after the monitor has been
started. If done when monitor is configured it will at startup
be done when services are not yet available and hence they will
not be populated with the dynamically discovered servers.
Storing all the runtime errors makes it possible to return all of them
them via the REST API. MaxAdmin will still only show the latest error but
MaxCtrl will now show all errors if more than one error occurs.
Because runtime changes are performed one at a time, adding replication credentials
to a mariadbmon which didn't have any would cause an error to be printed, and
the monitor would not start.
This is now fixed by allowing replication_user without replication_password. This
is not an ideal solution as a configuration file with only replication_user would be
accepted. Also, when adding the credentials to a monitor, replication_user must be
given first to avoid the error.
All servers are now updated in their own threads simultaneously. This
should reduce the possibility of having significantly different gtid:s
shown for different servers.
The functions are now in MonitorServer. Disk space can only be checked
during specific ticks. If a server misses a tick (e.g. is down) it will
be checked after disk_space_check_interval has passed.
This fixes some situations where MaxAdmin/MaxCtrl would block and wait
until a monitor operation or tick is complete. This also fixes a deadlock
caused by calling monitor diagnostics inside a monitor script.
Concurrency is enabled by adding one mutex per server object to protect
array-like fields from concurrent reading/writing.
Previously, runtime monitor modifications could directly alter monitor fields,
which could leave the text-form parameters and reality out-of-sync. Also,
the configure-function was not called for the entire monitor-object, only the
module-implementation.
Now, all modifications go through the overridden configure-function, which calls the
base-class function. As most configuration changes are given in text-form, this
removes the need for specific setters. The only exceptions are the server add/remove
operations, which must modify the text-form serverlist.
Was deprecated in 2.3. Similar features are in MariaDB-Monitor.
One system test was modified to use MariaDB-Monitor instead. Some parts
of the test are disabled for now to make it pass.
The monitor now continuously updates a list of enabled server events. When
promoting a new master in failover/switchover, only events that were enabled
on the previous master are enabled on the new. This avoids enabling events
that may have been disabled on the master yet stayed in the SLAVESIDE_DISABLED-
state on the slave.
In the case of reset-replication command, events on the new master are only
enabled if the monitor had a master when the command was launched. Otherwise
all events remain disabled.
Since the current node id can be obtained using the function gtmnid()
the queries for finding out whether a node is in the quorum and whether
it is softfailed can be made simpler.
When a softfailed node is finally revoked, it will appear as the
single node in a functioning Clustrix cluster. To ensure that the
Clustrix monitor will not stick to that node, if the node that is
used as hub is softfailed, it is immediately replaced with another
node.
Worker::STOPPED -> MONITOR_STATE_STOPPED
Worker::POLLING -> MONITOR_STATE_RUNNING
Worker::PROCESSING -> MONITOR_STATE_RUNNING
By defining the monitor state from the worker state there is
no risk they will ever get out of sync. And there is one thing
less to maintain.
When the servers of a service are defined by a monitor, then
at startup all servers of the monitor should be added to relevant
services. Likewise, when a server is added to or removed from a
monitor at runtime, those changes should affect services as well.
However, whether that should happen or not depends upon the monitor.
In the case of the Clustrix monitor this should not happen as it
adds and removes servers depending on the runtime state of the
Clustrix cluster.
The services whose servers are defined using a monitor, will
now be populated from the monitor.
Note, no consideration has yet been given to runtime changes.
The manipulation functions are currently static so that the container can be initialized
if required. This will be fixed later.
The new functions are taken into use in monitor management.
The default ECMAScript syntax appears to be broken on CentOS 7 which
effectively prevents its use in most cases. A more reliable alternative
would be to use the bundled PCRE2 library but the basic POSIX regular
expressions seem to work.
The likely reason for a node being down is that some cluster level
modifications have been performed. Consequently a cluster check should
be triggered in that case.
When checking the node info, also include information about wheter
a node is being SOFTFAILed. If it is, turn on the `Being Drained`
bit.
A node is SOFTFAILed with the intention of removing it, so better
not to create new connections to it as they later would be broken
when the node is actually taken down.
It is now possible to [un]softfail a Clustrix node via MaxScale
using a Clustrix monitor module command.
In case a node is successfully softfailed, the `Being Drained` bit
will automatically turned on. Similarly, if a node is successfully
unsoftfailed, the `Being Drained` bit will be cleared.
Since the settings are now protected fields, all related functions were
moved inside the monitor class. mon_ping_or_connect_to_db() is now a method
of MXS_MONITORED_SERVER. The connection settings class is defined inside the
server since that is the class actually using the settings.
