The SLEE specification defines the operational lifecycle of a SLEE — illustrated, defined, and summarised below.
SLEE lifecycle states
The SLEE lifecycle states are:
| State | Definition |
|---|---|
STOPPED |
The SLEE has been configured and initialised, and is ready to be started. Active resource adaptor entities have been loaded and initialised, and SBBs corresponding to active services have been loaded and are ready to be instantiated. The entire event-driven subsystem, however, is idle: resource adaptor entities and the SLEE are not actively producing events, the event router is not processing work, and the SLEE is not creating SBB entities. |
STARTING |
Resource adaptor entities in the SLEE that have been recorded in the management database as being in the ACTIVE state are started. The SLEE still does not create SBB entities. The node automatically transitions from this state to the RUNNING state when all startup tasks are complete, or to the STOPPING state if a startup task fails. |
RUNNING |
Activated resource adaptor entities in the SLEE can fire events, and the SLEE creates SBB entities and delivers events to them as needed. |
STOPPING |
Identical to the RUNNING state, except resource adaptor entities do not create (and the SLEE does not accept) new activity objects. Existing activity objects can end (according to the resource adaptor specification). The node automatically transitions out of this state, returning to the STOPPED state, when all SLEE activities have ended. The node can transition to this state directly from the STARTING state, effective immediately, if it has no activity objects. |
Independent SLEE states
Each namespace in each event-router node in a Rhino cluster maintains its own SLEE-lifecycle state machine, independent from other namespaces on the same or other nodes in the cluster. For example:
-
the default namespace on one node in a cluster might be in the RUNNING state
-
while a user-defined namespace on the same node is in the STOPPED state
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while the default namespace on another node is in the STOPPING state
-
and the user-defined namespace on that node is in the RUNNING state.
The operational state of each namespace on each cluster node persists to the disk-based database.
Bootup SLEE state
After completing bootup and initialisation, a namespace on a node will enter the STOPPED state if:
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the database has no persistent operational state information for that namespace on that node;
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the namespace’s persistent operational state is STOPPED on that node; or
-
the node was started with the
-xoption (see Start Rhino in the Rhino Getting Started Guide).
Otherwise, the namespace will return to the same operational state that it was last in, as recorded in persistent storage.
Changing a namespace’s operational state
You can change the operational state of any namespace on any node at any time, as long as least one node in the cluster is available to perform the management operation (regardless of whether or not the node whose operational state being changed is a current cluster member). For example, you might set the operational state of the default namespace on node 103 to RUNNING before node 103 is started — then, when node 103 is started, after it completes initialising, the default namespace will enter the RUNNING state.
|
Changing a quorum node’s operational state
You can also change the operational state of a node which is a current member of the cluster as a quorum node… but quorum nodes make no use of operational state information stored in the database, and will not respond to operational state changes. (A node only uses operational state information if it starts as a regular event-router node.) |
