94e04c8de2
When taking a snapshot of a replicated share, users would
expect the snapshot to be available across the replicas.
Currently, Manila assumes that drivers will take snapshots
along with the share data.
Different backends implement replication differently. Many
of them assume that replicas are 'in_sync' with the primary
if they have been synchronized within a particular window
of time (sometimes referred to as 'recovery point objective').
Since snapshots are point in time actions on a share, drivers
must ensure that the replication of a snapshot begins as soon
as it is available on the primary/'active' instance.
To ensure that snapshots are indeed available across replicas:
1) Track snapshots across replicas as different
snapshot instances.
2) Make an 'aggregate_status' property to convey the
availability of a snapshot across all the active/in_sync
replicas of a share.
3) Provide all the information necessary for drivers to:
- Create a snapshot on the primary and send it across
to all replicas
- Delete a snapshot on the primary and ensure that it is
deleted on the replicas as well.
4) Set snapshot instance to 'error' if it was in any transitional
state when its replica was 'promoted' to become an 'active'
instance.
5) Pass down snapshot instances during create, delete and update
replica driver calls.
6) Update replica interfaces to pass in snapshot instance data. Always
include 'available' snapshots in the update_replica call to ensure
that drivers confirm their presence on the replica in order to report
that the replica is 'in_sync'.
Also, grab the share_type afresh from parent share/snapshot
to allow 'replication_key' to be copied to the share model during
share creation.
Rename SnapshotNotFound to SnapshotResourceNotFound to
signify a missing snapshot object on backends.
APIImpact
The 'status' attribute of the snapshot is now the 'aggregate_status'
of the instances of the snapshot. No key changes have been made
in the JSON response. However, API actions will be gated against
'aggregate_status' of the snapshot instances when more than one
instance exists.
Closes-Bug: #1546303
Closes-Bug: #1551064
Change-Id: I63203df00904d209e9e92eda7c79206e5ef8d611
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| .. | ||
| contrib | ||
| middleware | ||
| openstack | ||
| v1 | ||
| v2 | ||
| views | ||
| __init__.py | ||
| auth.py | ||
| common.py | ||
| extensions.py | ||
| sizelimit.py | ||
| urlmap.py | ||
| versions.py | ||