Using System State Manager › SSM Concepts › Understanding CURRENT and DESIRED Resource States

Understanding CURRENT and DESIRED Resource States

The terms desired state and current state refer to the contents of the DESIRED_STATE and CURRENT_STATE columns respectively for a selected resource. These columns can be set to any value that is convenient for automation needs. For example, current state can be set to INIT, STARTING, STOPPING, ACTIVE, and so on.

abstract states

SSM defines three abstract states, named UP, DOWN, and UNKNOWN. The state names that represent these states for tables are known as the table-relative UP, DOWN, and UNKNOWN states. Each resource table can have its own name for these three states; however, you can define new names to the table-relative UP and DOWN states only when adding a resource table to the SSM directory table. For example, one table of resources can have ACTIVE defined as its table-relative UP state and INACTIVE defined as its table-relative DOWN state. Another resource table can have ONLINE and OFFLINE defined as it's table-relative UP and DOWN states respectively. SSM recognizes the table-relative value by comparing the CURRENT_STATE and DESIRED_STATE columns with the UP_STATE, DOWN_STATE, and UNKNOWN_STATE columns in the directory table.

table-relative states

The state that the CURRENT_STATE and DESIRED_STATE columns are actually set to, such as ACTIVE, INACTIVE, ONLINE, and OFFLINE are table-relative states. References to the UP state refer to the table-relative state that is designated as UP. For each resource table, the value of the UP and DOWN states is defined in the directory table. The table-relative UP, DOWN, and UNKNOWN states can be referred to symbolically in action text with the corresponding column names of the SSM directory table, such as &UP_STATE, &DOWN_STATE, and &UNKNOWN_STATE.

Current state is the actual state of the resource as it appears on the system. Desired state is the state in which a resource should be. For example, if you want a subsystem to be up (desired state is UP) but it is down (current state is DOWN), the action text could be a command to start or restart the subsystem.

Note: SSM records all actions taken in response to resource state changes in OPSLOG.