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doc: correct rbd snap-clone doc

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Signed-off-by: Humble Chirammal <hchiramm@redhat.com>
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Humble Chirammal 2020-08-08 13:19:02 +05:30 committed by mergify[bot]
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docs/design/proposals/rbd-snap-clone.md
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@ -2,7 +2,7 @@
- [Steps and RBD CLI commands for RBD snapshot and clone operations](#steps-and-rbd-cli-commands-for-rbd-snapshot-and-clone-operations)
- [Create a snapshot from PVC](#create-a-snapshot-from-pvc)
- [steps to creating a snapshot](#steps-to-creating-a-snapshot)
- [steps to create a snapshot](#steps-to-create-a-snapshot)
- [RBD CLI commands to create snapshot](#rbd-cli-commands-to-create-snapshot)
- [Create PVC from a snapshot (datasource snapshot)](#create-pvc-from-a-snapshot-datasource-snapshot)
- [steps to create a pvc from snapshot](#steps-to-create-a-pvc-from-snapshot)
@ -18,25 +18,25 @@
- [RBD CLI commands to create a Volume from Volume](#rbd-cli-commands-to-create-a-volume-from-volume)
This document outlines the command used to create RBD snapshot, delete RBD
snapshot Restore RBD snapshot and Create New RBD image from RBD image.
snapshot, Restore RBD snapshot and Create new RBD image from existing RBD image.
## Create a snapshot from PVC
Refer [snapshot](https://kubernetes.io/docs/concepts/storage/volume-snapshots/)
for more information realted to Volume cloning in kubernetes.
### steps to creating a snapshot
### steps to create a snapshot
- Check if the parent image has more snapshots than the configured value, if
its has more snapshot Add tasks to flatten all the temporary cloned images
it has more snapshot, add tasks to flatten all the temporary cloned images
and return ResourceExhausted error message
- Create a temporary snapshot from the parent image
- Clone a new image from a temporary snapshot with options
--rbd-default-clone-format 2 --image-feature layering,deep-flatten
`--rbd-default-clone-format 2 --image-feature layering,deep-flatten`
- Delete temporary snapshot created
- Check the image chain depth, if the Softlimit is reached Add a task Flatten
the cloned image and return success. If the depth is reached hardlimit Add a
task Flatten the cloned image and return snapshot status ready as false
- Check the image chain depth, if the `softlimit` is reached add a task to flatten
the cloned image and return success. If the depth is reached `hardlimit` add a
task flatten the cloned image and return snapshot status ready as `false`
### RBD CLI commands to create snapshot
@ -44,16 +44,16 @@ for more information realted to Volume cloning in kubernetes.
[$] rbd snap ls <RBD image for src k8s volume> --all
// If the parent has more snapshots than the configured `maxsnapshotsonimage`
add backgound tasks to flatten the temporary cloned images( temporary cloned
images name will be same as snapshot names)
image names will be same as snapshot names)
[$] ceph rbd task add flatten <RBD image for temporary snap images>
[$] rbd snap create <RBD image for src k8s volume>@<random snap name>
[$] rbd clone --rbd-default-clone-format 2 --image-feature
layering,deep-flatten <RBD image for src k8s volume>@<random snap>
<RBD image for temporary snap image>
[$] rbd snap rm <RBD image for src k8s volume>@<random snap name>
[$] rbd snap create <BD image for temporary snap image>@<random snap name>
[$] rbd snap create <RBD image for temporary snap image>@<random snap name>
// check the depth, if the depth is greater than configured hardlimit add a
// task to flatten the cloned image return snapshot status ready as false,
// task to flatten the cloned image, return snapshot status ready as `false`,
// if the depth is greater than softlimit add a task to flatten the image
// and return success
[$] ceph rbd task add flatten <RBD image for temporary snap image>
@ -63,7 +63,7 @@ images name will be same as snapshot names)
### steps to create a pvc from snapshot
- Check the depth(n) of the cloned image if n>=(hardlimit -2) Add task to
- Check the depth(n) of the cloned image if `n>=(hardlimit -2)`, add task to
flatten the image and return ABORT (to avoid image leak)
- Clone a new image from the snapshot with user-provided options
@ -101,8 +101,8 @@ images name will be same as snapshot names)
## Delete a Volume (PVC)
With earlier implementation to delete the image we used to add a task to remove
the image with new changes this cannot be done as the image may contains
snapshots or linking.so we will be following below steps to delete an
the image. With new changes this cannot be done as the image may contains
snapshots or linking, so we will be following below steps to delete an
image(this will be applicable for both normal image and cloned image)
### steps to delete a volume
@ -125,8 +125,8 @@ for more information realted to Volume cloning in kubernetes.
### steps to create a Volume from Volume
- Check the depth(n) of the cloned image if n>=((hard limit) -2) Add task to
flatten the image and return about (to avoid image leak)
- Check the depth(n) of the cloned image if `n>=((hard limit) -2)`, add task to
flatten the image and return ABORT (to avoid image leak)
- Create snapshot of rbd image
- Clone the snapshot (temp clone)
- Delete the snapshot