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Diffstat (limited to 'docs/requirements/03-architecture.rst')
| -rw-r--r-- | docs/requirements/03-architecture.rst | 34 |
1 files changed, 20 insertions, 14 deletions
diff --git a/docs/requirements/03-architecture.rst b/docs/requirements/03-architecture.rst index 8ff5dacf..b7417691 100644 --- a/docs/requirements/03-architecture.rst +++ b/docs/requirements/03-architecture.rst @@ -191,11 +191,15 @@ fencing, but there has not been any progress. The general description is available here: https://wiki.openstack.org/wiki/Fencing_Instances_of_an_Unreachable_Host -As OpenStack does not cover fencing it is in the responsibility of the Doctor -project to make sure fencing is done by using tools like pacemaker and by -calling OpenStack APIs. Only after fencing is done OpenStack resources can be -marked as down. In case there are gaps in OpenStack projects to have all -relevant resources marked as down, those gaps need to be identified and fixed. +OpenStack provides some mechanisms that allow fencing of faulty resources. Some +are automatically invoked by the platform itself (e.g. Nova disables the +compute service when libvirtd stops running, preventing new VMs to be scheduled +to that node), while other mechanisms are consumer trigger-based actions (e.g. +Neutron port admin-state-up). For other fencing actions not supported by +OpenStack, the Doctor project may suggest ways to address the gap (e.g. through +means of resourcing to external tools and orchestration methods), or +documenting or implementing them upstream. + The Doctor Inspector component will be responsible of marking resources down in the OpenStack and back up if necessary. @@ -206,18 +210,18 @@ In the basic :ref:`uc-fault1` use case, no automatic actions will be taken by the VIM, but all recovery actions executed by the VIM and the NFVI will be instructed and coordinated by the Consumer. -In a more advanced use case, the VIM shall be able to recover the failed virtual +In a more advanced use case, the VIM may be able to recover the failed virtual resources according to a pre-defined behavior for that resource. In principle this means that the owner of the resource (i.e., its consumer or administrator) can define which recovery actions shall be taken by the VIM. Examples are a -restart of the VM, migration/evacuation of the VM, or no action. +restart of the VM or migration/evacuation of the VM. High level northbound interface specification --------------------------------------------- -Fault management +Fault Management ^^^^^^^^^^^^^^^^ This interface allows the Consumer to subscribe to fault notification from the @@ -261,7 +265,8 @@ physical resource from 'enabled' to 'going-to-maintenance' and a timeout [#timeo After receiving the MaintenanceRequest,the VIM decides on the actions to be taken based on maintenance policies predefined by the affected Consumer(s). -.. [#timeout] Timeout is set by the Administrator and corresponds to the maximum time to empty the physical resources. +.. [#timeout] Timeout is set by the Administrator and corresponds to the maximum time + to empty the physical resources. .. figure:: images/figure5a.png :name: figure5a @@ -321,12 +326,13 @@ An example of a high level message flow to cover the failed NFVI maintenance cas shown in :numref:`figure5c`. It consists of the following steps: -5. The Consumer C3 switches to standby configuration (STDBY). -6. Instructions from Consumers C2/C3 are shared to VIM requesting certain actions to be performed (steps 6a, 6b). - The VIM executes the requested actions and sends back a NACK to consumer C2 (step 6d) as the - migration of the virtual resource(s) is not completed by the given timeout. +5. The Consumer C3 switches to standby configuration (STBY). +6. Instructions from Consumers C2/C3 are shared to VIM requesting certain actions to be performed + (steps 6a, 6b). The VIM executes the requested actions and sends back a NACK to consumer C2 + (step 6d) as the migration of the virtual resource(s) is not completed by the given timeout. 7. The VIM switches the physical resources to "enabled" state. -8. MaintenanceResponse is sent from VIM to inform the Administrator that the maintenance action cannot start. +8. MaintenanceNotification is sent from VIM to inform the Administrator that the maintenance action + cannot start. .. |