The locking feature is a part of the Hardware State Manager (HSM) API. The locking API enables administrators to lock components on the system. Locking components ensures other system actors, such as administrators or running services, cannot perform a firmware update with the Firmware Action Service (FAS) or a power state change with the Power Control Service (PCS) or Cray Advanced Platform Monitoring and Control (CAPMC).
Locks only constrain FAS and PCS/CAPMC from each other, and help ensure that a firmware update action will not be interfered with by a request to power off the device through PCS/CAPMC. Locks only work with HMS services and will not impact other system services.
Note: Starting in CSM 1.7, the Boot Orchestration Service (BOS) is aware of HSM locks. For more information, see BOS sessions and HSM locks.
Locks can only be used to prevent firmware updates with FAS or power state changes with CAPMC/PCS.
Administrators can still use HMS APIs to view the state of various hardware components on the system, even if a lock is in place. There is no automatic locking for hardware devices. Locks need to be manually set or unset by an administrator. A scenario that might be encountered is when a larger hardware state change job is run, and one of the components in the job has a lock on it. If FAS is the service running the job, FAS will attempt to update the firmware on each component, and will update all devices that do not have a lock on it. The job will not complete until the node lock ends, or if a timeout is set for the job.
The locking API also includes actions to repair or disable a node’s locking ability with respect to HMS services. The disable function will make it so a device cannot be firmware updated or power controlled (via an HMS service) until a repair is done. Future requests to perform a firmware update via FAS or power state change via PCS/CAPMC cannot be made on that component until the repair action is used.
WARNING: System administrators should LOCK management NCNs after the system has been brought up, in order to prevent an administrator from unintentionally firmware updating or powering off an NCN. Without these locks, an authorized request to FAS or PCS/CAPMC could power off the NCNs, which may negatively impact system stability and the health of services running on those NCNs. See Lock and Unlock Management Nodes.
For more information, see Manage HSM Locks.