@Punditji Thank you for your query.
AKS generally have two kind of pods. Stateful pods and stateless pod. Stateful pods already have azure volumes or file system as storage layer for it.
Backup of AKS nodes might not help as nodes can come and go without any issue. Disks attached of AKS is not required for backup. However in case of stateful pods, volumes should be backed up in order to avoid any issue due to that.
More information about it can be read here.
For backup of Azure Content Registry, one of the way is to geo replicate it across Geo. More information can be read here.
Another way to do so it to write custom hooks which can pull images once new images are pushed and backup the content of the images in ACR.
Hope it helps.
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