chore(design): adding pv migration proposal #336
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Signed-off-by: Pawan <pawan@mayadata.io>
Signed-off-by: Pawan <pawan@mayadata.io>
Signed-off-by: Pawan <pawan@mayadata.io>
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cc: @iyashu Please take a look. |
Signed-off-by: Pawan <pawan@mayadata.io>
design/pv-migration.md
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| ### Workflow | ||
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| - user will setup all the nodes and setup the ZFS pool on each of those nodes. | ||
| - the ZFS-LocalPV CSI driver will look for all the pools on the node and will set the `guid.openebs.io/<pool-guid>=true` label for all ZFS POOLs that is present on that node. Let's say node-1 has two pools(say pool1 with guid as 14820954593456176137 and pool2 with guid as 16291571091328403547) present then the labels will be like this : |
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q_: Does k8s put a limit on the number of labels that can be attached to the node?
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there are cloud providers which have some limit like gcp has limit of 64.
design/pv-migration.md
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| - we can simply import the pool and restart the ZFS-LocalPV driver to make it aware of that pool to set the corresponding node topology | ||
| - the ZFS-LocalPV driver will look for `guid.openebs.io/14820954593456176137=true` and will remove the label from the nodes where pool is not present | ||
| - the ZFS-LocalPV driver will update the new node with `guid.openebs.io/14820954593456176137=true` label |
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q_: How to avoid a race conditions where two nodes in the cluster will have the same label? Also consider the cases like:
- Node is shutdown or in not ready state and the pools have been moved to new node.
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previous step handles that, it has to make sure there are no node with the same label.
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in the previous steps - ZFS - Local PV driver - is it the node driver running on the old node or new node?
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Yes, the node driver will remove/set the label.
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in uninstall, cases - will the labels be cleared from nodes.
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do we need that, at the installation time, node label will be handle/moved accordingly. Btw CSI does not provide any framework to unset the topology. We can only set it at the registration time only. But can be done out of the box.
Signed-off-by: Pawan <pawan@mayadata.io>
Signed-off-by: Pawan <pawan@mayadata.io>
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Is there still something missing from this proposal, which blocks it from being merged? Else it could be a first step towards an implementation of #291. Merging it would signal that this feature is still considered, while the discussion is stalled, that could be continued in pair with a reference implementation. |
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@pawanpraka1 It would be great if you contribute this feature(code) to this repo. We are our hands full of other openebs engines work at the moment, and i don't see we will be able to code for this improvement. |
Signed-off-by: Pawan pawan@mayadata.io