6.7. Connector/Manager Interface
The connector remains in constant communication with the Tungsten Manager
during operation. This enables the connector to respond to failures and
errors, whether automatically identified, or manually triggered. For
example, when a manual switch
operation occurs, the manager communicates this information to all of the
connectors. Each connector then responses according to the rules outline
in Section 6.6, “Connector Operational States”.
The connector remains in communication with one, and only one, manager at
a time. If the manager becomes unavailable, connector tries to communicate
another manager within the dataservice.
Communication from the manager to the connectors is made in parallel using
multiple threads, this ensures that all connectors are made aware of a
change in the topology of the cluster at the same time, rather than a
round-robin or staged distribution. When a change has been requested, the
manager waits for a response from the cluster before confirming that
switch and operational change has taken place.
Communication between managers and the connectors is handled on ports
11999 (managed by
and 12000 (managed by
--mgr-rmi-remote-port). The connection is
used to exchange cluster status and individual datasource availability as
identified by the manager so that decisions about active connections can
be effectively made by the connector.
In the event that the connection between the connector and the manager is
broken, the connector enters a failsafe mode called
On Hold. In this state,
connections to and from the connector and datasources will continue as
normal until a timeout, configured by the
property, is reached. By default, this timeout is 600 seconds (10
minutes). Once the timeout has been reached, the connector reaches the
All of the information about the dataservice, including the other nodes,
topology and individual node states and roles are entirely determined by
the Connector by requesting this information from the Manager. No on-disk
record or description is stored or stored, created, or read by the
Connector. When the Connector is first started, it connects to a manager
and requests the full cluster configuration.
If the Connector cannot communicate with a manager, the connector remains
Offline state until
a manager can be reached.