4.5. Managing

Many management actions, such as adding new SLA templates or new functional services, will involve changes to the configuration. There are a few other cases where the service manager would have to intervene.

Suspending, Resuming and Closing SLAs

An SLA has four states: active, suspended, closing and closed. The transitions between the states are shown in the diagram below:

The service manager may sometimes want to change the state of an SLA. To understand the state model, the states are described here:

Active

This is the normal state, entered into when an SLA is created. The active state is also entered if the service manager clicks on the "Resume" button in the web application by a suspended SLA. When the SLA is active, the SLA service will process requests from functional services to start new actions against the SLA's usage constraint terms.

Suspended

This state is entered if the SLA service finds it is unable to bill the account service for the SLA. This would occur at the end of a billing period if the SLA's account was suspended or closed. The state may also be entered into if the service manager clicks on the "Suspend" button by the SLA in the web application. When an SLA is in the suspended state, no new actions may be performed that would result in resource usage.

Closing

The closing state is entered when either the client chooses "Close SLA" on an SLA in the client, or when the service manager clicks on the "Close" button by the SLA in the web application. When an SLA enters the closing state, all running activities are signaled to destroy (so, for instance, all data in data stagers would be lost). The SLA remains in this state until all activities have finished and the final bill has been sent. No new activities may be started in this state. If really necessary, the "Force close" action may be used. Using this button puts the SLA into the "Closed" state and stops the SLA service from managing all the SLA's remaining activities but does not try to destroy the activities. The account is also not billed (unbilled charges can be seen on an SLA's page).

Closed

The closed state is entered when the final bill has successfully been sent to the account service and there are no more running activities in the SLA. No new activities may be started in this state.

Stopping Activities and Services From Being Managed

There are some unusual situations when you may need to intervene to tell the SLA service to stop managing an activity. As noted above, an SLA will remain in the closing state until it determines that all activities in the SLA have finished. Occasionally, the message indicating that an activity has finished may be lost (for instance, if the server running the functional service crashes). If this happened, then the SLA would never reach the closed state. For this emergency use only, a button is provided by each activity in the activity list for an SLA labelled "Stop Managing". Pressing this button will force the SLA service to behave as though it had received a message saying that the activity had finished. Pressing the "Stop Managing" button does not communicate with the functional service owning the activity - it does not destroy the resource. It just means the SLA Service will no longer take any responsibility for managing the functional service activity against the SLA terms.

In addition, the "Managed Services" page (see the end of the main SLA service administration page) shows which functional services are currently being managed. Services on this list come and go automatically: they appear when a functional service tells the SLA service to manage a new activity and are removed when there are no more activities left to manage on a service. While a service is on the list, the SLA service periodically polls it to gather usage information. Clicking on the functional service in this list displays all activities that the SLA Service is managing at a functional service (e.g. all jobs and data).

If a functional service fails then the SLA Service will continue trying to gather usage information. As a last resort it is possible to tell the SLA Service to "Stop managing" a functional service. This forces the SLA Service will finish all the activities it is managing at the service (and therefore stop polling it).

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