forked from rook/rook
Blaine Gardner
3c43268d0a
Change how Rook detects network CIDRs for Multus networks. The IPAM configuration is only defined as an arbitrary string JSON blob with a "type" field and nothing more. Rook's detection of CIDRs for whereabouts had already grown out of date since the initial implementation. Additionally, Rook did not support DHCP IPAM, which is a reasonable choice for users. And more, Rook did not support CNI plugin chaining, which further complicates NADs. Based on the CNI spec, network chaning can result in any changes to network CIDRs from the first-given plugin. All these problems make it more and more difficult for Rook to support Multus by inspecting the NAD itself to predict network CIDRs. Instead, it is better for Rook to treat the CNI process as a black box. To preserve legacy functionality of auto-detecting networks and to make that as robust as possible, change to a canary-style architecture like that used for Ceph mons, from which Rook will detect the network CIDRs if possible. Also allow users to specify overrides for CIDR ranges. This allows Rook to still support esoteric and unexpected NAD or network configurations where a CIDR range is not detectable or where the range detected would be incomplete. Because it may be impossible for Rook to understand the network CIDRs wholistically while residing only on a portion of the network, this feature should have been present from Multus's inception. Improving CIDR auto-detection and allowing users to specify overrides for auto-detected CIDRs rounds out Rook's Multus support for CephCluster (core/RADOS) installations. No further architectural changes should be needed for CephClusters as regards application of public/cluster network CIDRs for Multus networks. Signed-off-by: Blaine Gardner <blaine.gardner@ibm.com>