feat: add snapshot max count and size

[FrankYang0529]

ref: longhorn/longhorn#6563

rely on:

• feat: add snapshot max count and size longhorn-instance-manager#286
• feat: add snapshot max count and size longhorn-engine#933

Test Plan:

snapshot-max-count setting

• Test the default value is 250.
• Test its value should be integer and between 2 to 250.
• Update the setting to 5 and create a Volume without snapshotMaxCount. The default snapshotMaxCount on the Volume will be 5.

snapshotMaxCount in Volume & updateSnapshotMaxCount action

• Test we can't create a volume with snapshotMaxCount which is lower than 2 or more than 250.
• Create a volume with snapshotMaxCount=3 and snapshotMaxSize=0.
• Attach the volume with maintenance mode.
• Create two snapshots.
• Revert to the first snapshot. (volume-head will be on the second branch)
• Create the third snapshot.
• Revert to the first snapshot. (volume-head will be on the third branch)
• Should not be able to create a new snapshot, because we already have 3 snapshots.
• Use updateSnapshotMaxCount action to update snapshotMaxCount to 4.
• Create the fourth snapshot.
• Should not be able to use updateSnapshotMaxCount action to update snapshotMaxCount to 3, because we can't make snapshotMaxCount be smaller than current usage.
• Delete a snapshot.
• Use updateSnapshotMaxCount action to update snapshotMaxCount to 3.

snapshotMaxSize in Volume & updateSnapshotMaxSize action

• Test we can't create a volume with snapshotMaxSize which is more than 0 and lower than 2 * volume.spec.size.
• Create a volume with size=1073741824 (1G), snapshotMaxCount=250 and snapshotMaxSize=2357198848 (2.2G).
• Create a related PV/PVC.
• Use a pod to mount volume.
• Create file1 with 950M in the volume.
• Create the first snapshot.
• Remove the file1 and create file2 with 950M in the volume.
• Create the second snapshot.
• Remove the file2 and create file3 with 950M in the volume.
• Should not be able to create a new snapshot, because the total snapshot size will be more than 2.2G.
• Use updateSnapshotMaxSize action to update snapshotMaxSize to 3430940672 (3.2G).
• Create the third snapshot.
• Should not be able to use updateSnapshotMaxSize action to update snapshotMaxSize to 2357198848 (2.2G), because we can't make snapshotMaxSize be smaller than current usage.
• Delete a snapshot.
• Use updateSnapshotMaxSize action to update snapshotMaxSize to 2357198848 (2.2G).

upgrade test

• Create a volume in LH v1.5.x.
• Upgrade to v1.6.0-dev and check there is no error on the volume.

[innobead]

Why kubebuilder:validation:Type=string instead of int?

[FrankYang0529]

I followed VolumeSpec.Size. @derekbit, could you share the idea to use string validation? This was added from #1136. Thank you.

longhorn-manager/k8s/pkg/apis/longhorn/v1beta2/volume.go

Lines 210 to 213 in 9cb537d

	type VolumeSpec struct {
	// +kubebuilder:validation:Type=string
	// +optional
	Size int64 `json:"size,string"`

[mergify]

This pull request is now in conflicts. Could you fix it @FrankYang0529? 🙏

[mergify]

This pull request is now in conflicts. Could you fix it @FrankYang0529? 🙏

[mergify]

This pull request is now in conflicts. Could you fix it @FrankYang0529? 🙏

[innobead]

A few comments.