lxd/instance_post: Prevent live migration of instances with custom vo…

…lumes

Signed-off-by: Din Music <din.music@canonical.com>

lxd/instance_post.go

@@ -17,6 +17,7 @@ import (
 	"github.com/canonical/lxd/lxd/db"
 	dbCluster "github.com/canonical/lxd/lxd/db/cluster"
 	"github.com/canonical/lxd/lxd/db/operationtype"
+	"github.com/canonical/lxd/lxd/device"
 	"github.com/canonical/lxd/lxd/instance"
 	"github.com/canonical/lxd/lxd/instance/instancetype"
 	"github.com/canonical/lxd/lxd/operations"
@@ -618,7 +619,7 @@ func instancePostMigration(s *state.State, inst instance.Instance, newName strin
 	return nil
 }
 
-// Move a non-ceph container to another cluster node.
+// Move an instnace to another cluster node. Source and target members must be online.
 func instancePostClusteringMigrate(s *state.State, r *http.Request, srcPool storagePools.Pool, srcInst instance.Instance, newInstName string, srcMember db.NodeInfo, newMember db.NodeInfo, stateful bool, allowInconsistent bool) (func(op *operations.Operation) error, error) {
 	srcMemberOffline := srcMember.IsOffline(s.GlobalConfig.OfflineThreshold())
 
@@ -629,7 +630,7 @@ func instancePostClusteringMigrate(s *state.State, r *http.Request, srcPool stor
 	}
 
 	// Save the original value of the "volatile.apply_template" config key,
-	// since we'll want to preserve it in the copied container.
+	// since we'll want to preserve it in the copied instance.
 	origVolatileApplyTemplate := srcInst.LocalConfig()["volatile.apply_template"]
 
 	// Check we can convert the instance to the volume types needed.
@@ -956,7 +957,25 @@ func migrateInstance(s *state.State, r *http.Request, inst instance.Instance, ta
 		return err
 	}
 
-	// Check if we are migrating a ceph-based instance.
+	// In case of live migration, ensure all instance disks can be migrated.
+	if req.Live && inst.IsRunning() {
+		volatileGet := func() map[string]string { return map[string]string{} }
+		volatileSet := func(_ map[string]string) error { return nil }
+		for deviceName, rawConfig := range inst.ExpandedDevices() {
+			dev, err := device.New(inst, s, deviceName, rawConfig, volatileGet, volatileSet)
+			if err != nil {
+				return err
+			}
+
+			devConfig := dev.Config()
+
+			if devConfig["type"] == "disk" && !shared.IsRootDiskDevice(devConfig) {
+				return fmt.Errorf("Cannot live migrate instance with attached custom volume")
+			}
+		}
+	}
+
+	// Retrieve storage pool of the source instance.
 	srcPool, err := storagePools.LoadByInstance(s, inst)
 	if err != nil {
 		return fmt.Errorf("Failed loading instance storage pool: %w", err)