add example for disk conversion #57
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bennyz
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| @@ -0,0 +1,82 @@ | |||
| #!/usr/bin/env python | |||
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| """ | ||
| Show how to download disk snapshots using imageio client. | ||
| Requires the ovirt-imageio-client package. |
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Need to replace with relevant text
| # Start the conversion to raw/preallocated | ||
| if args.format == 'raw': | ||
| disk_format = types.DiskFormat.RAW | ||
| elif args.format == 'cow': |
| disk_service.convert( | ||
| disk=types.Disk( | ||
| format=disk_format, | ||
| sparse=args.sparse) |
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What will happen if user choose:
format="raw", sparse=True
On block storage, or:
format="cow", sparse=False
On any storage?
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It fails on engine's validation:
ovirtsdk4.Error: Fault reason is "Operation Failed". Fault detail is "[Cannot convert disk Virtual Disk. Disk configuration (COW Preallocated backup-None) is incompatible with the storage domain type.]". HTTP response code is 409.
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We need to make cow-prellocated possible, this is required for incremental backup.
| while True: | ||
| time.sleep(1) | ||
| disk = disk_service.get() | ||
| if disk.status == types.DiskStatus.OK: |
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Waiting for disk status is usually broken because when change the status before the
disk is unlocked. Do we have better way to wait? use jobs?
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This is an async operation, but the memory lock is released before before the status change so we shouldn't have that race condition
| disk_format = types.DiskFormat.RAW | ||
| elif args.format == 'cow': | ||
| disk_format = types.DiskFormat.COW | ||
| disk_service.convert( |
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Need to account for the case where format isn't passed
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You can make both format and sparse required=True, but do we want to support convert
from raw-sparse to raw-preallocated? seems resonable to me.
So the rule can be, specify either format or sparse or both.
What about validation with current disk properties? For example:
disk format: raw
disk sparse: true
format: raw
sparse: true
Or the case when the disk does not exists.
I guess this validation is on the backend, but I think good application will validate
this on the client side to avoid sending pointless requests.
So I think the flow should be:
get the disk
fail if the disk does not exist
validate the parameters with the disk
fail if we have nothing to do, or the requested parameters cannot be used.
convert the disk
wait until conversion completes
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yes, the parameters are optional (only one is required)
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| parser.add_argument( | ||
| "--sparse", | ||
| type=bool, |
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this can't actually be a bool, if it's not passed we don't want to change the allocation policy
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The way to add bool arguments is:
parser.add_argument("--sparse", action="store_true")
If not set, args.sparse will be None. We can use this for
keep the current format.
Same for the format - if the user does not set the foramt,
we want to keep the current format.
depends on oVirt/ovirt-engine#51
and new sdk release