Merge pull request kubernetes#29622 from rootfs/rbd-ro

Automatic merge from submit-queue allow a read-only rbd image mounted by multiple pods allow pod to run read-only rbd volume fix kubernetes#27725
lavalamp · Aug 8, 2016 · faffbe4 · faffbe4
2 parents e19ea41 + 730db45
commit faffbe4
Showing 1 changed file with 4 additions and 1 deletion.
diff --git a/plugin/pkg/scheduler/algorithm/predicates/predicates.go b/plugin/pkg/scheduler/algorithm/predicates/predicates.go
@@ -121,7 +121,10 @@ func isVolumeConflict(volume api.Volume, pod *api.Pod) bool {
 		if volume.RBD != nil && existingVolume.RBD != nil {
 			mon, pool, image := volume.RBD.CephMonitors, volume.RBD.RBDPool, volume.RBD.RBDImage
 			emon, epool, eimage := existingVolume.RBD.CephMonitors, existingVolume.RBD.RBDPool, existingVolume.RBD.RBDImage
-			if haveSame(mon, emon) && pool == epool && image == eimage {
+			// two RBDs images are the same if they share the same Ceph monitor, are in the same RADOS Pool, and have the same image name
+			// only one read-write mount is permitted for the same RBD image.
+			// same RBD image mounted by multiple Pods conflicts unless all Pods mount the image read-only
+			if haveSame(mon, emon) && pool == epool && image == eimage && !(volume.RBD.ReadOnly && existingVolume.RBD.ReadOnly) {
 				return true
 			}
 		}