Implement VM_appliance.recover

This method recovers all the VMs in the appliance, then tries to
recreate the appliance object. If an appliance with the same UUID
exists, the error is caught and the recovered appliance will have a new
UUID.

Signed-off-by: John Else <john.else@citrix.com>

ocaml/idl/datamodel.ml

@@ -6546,6 +6546,16 @@ let vm_appliance =
 		~doc:"Assert whether all SRs required to recover this VM appliance are available."
 		~allowed_roles:_R_READ_ONLY
 		() in
+	let vm_appliance_recover = call
+		~name:"recover"
+		~in_product_since:rel_boston
+		~params:[Ref _vm_appliance, "self", "The VM appliance to recover";
+			Ref _session, "session_to", "The session to which the VM appliance is to be recovered.";
+			Bool, "force", "Whether the VMs should replace newer versions of themselves."]
+		~errs:[Api_errors.vm_requires_sr]
+		~doc:"Recover the VM appliance"
+		~allowed_roles:_R_READ_ONLY
+		() in
 	create_obj ~in_db:true ~in_product_since:rel_boston ~in_oss_since:None ~internal_deprecated_since:None ~persist:PersistEverything ~gen_constructor_destructor:true ~name:_vm_appliance ~descr:"VM appliance"
 		~gen_events:true
 		~doccomments:[]
@@ -6555,6 +6565,7 @@ let vm_appliance =
 			vm_appliance_clean_shutdown;
 			vm_appliance_hard_shutdown;
 			vm_appliance_assert_can_be_recovered;
+			vm_appliance_recover;
 		]
 		~contents:([
 			uid _vm_appliance;

ocaml/xapi/message_forwarding.ml

@@ -586,6 +586,10 @@ module Forward = functor(Local: Custom_actions.CUSTOM_ACTIONS) -> struct
 		let assert_can_be_recovered ~__context ~self ~session_to =
 			info "VM_appliance.assert_can_be_recovered: VM_appliance = '%s'" (vm_appliance_uuid ~__context self);
 			Local.VM_appliance.assert_can_be_recovered ~__context ~self ~session_to
+
+		let recover ~__context ~self ~session_to ~force =
+			info "VM_appliance.recover: VM_appliance = '%s'" (vm_appliance_uuid ~__context self);
+			Local.VM_appliance.recover ~__context ~self ~session_to ~force
 	end
 	module DR_task = Local.DR_task
   (* module Alert = Local.Alert *)

ocaml/xapi/xapi_dr.ml

@@ -38,6 +38,7 @@ let recover_vms ~__context ~vms ~session_to ~force =
 			in
 			try
 				Import.complete_import ~__context:__context_to vmrefs;
+				vmrefs
 			with e ->
 				if force then
 					debug "%s" "VM recovery failed - not cleaning up as action was forced."

ocaml/xapi/xapi_vm.ml

@@ -1292,4 +1292,4 @@ let recover ~__context ~self ~session_to ~force =
 	(* Check the VM SRs are available. *)
 	assert_can_be_recovered ~__context ~self ~session_to;
 	(* Attempt to recover the VM. *)
-	Xapi_dr.recover_vms ~__context ~vms:[self] ~session_to ~force
+	ignore (Xapi_dr.recover_vms ~__context ~vms:[self] ~session_to ~force)

ocaml/xapi/xapi_vm_appliance.ml

@@ -175,3 +175,27 @@ let assert_can_be_recovered ~__context ~self ~session_to =
 	List.iter
 		(fun vm -> Xapi_vm_helpers.assert_can_be_recovered ~__context ~self:vm ~session_to)
 		vms
+
+let recover ~__context ~self ~session_to ~force =
+	assert_can_be_recovered ~__context ~self ~session_to;
+	let vms = Db.VM_appliance.get_VMs ~__context ~self in
+	let recovered_vms = Xapi_dr.recover_vms ~__context ~vms ~session_to ~force in
+	(* Recreate the VM appliance object. *)
+	let old_appliance = Db.VM_appliance.get_record ~__context ~self in
+	Server_helpers.exec_with_new_task ~session_id:session_to "Recreating VM appliance object"
+		(fun __context_to ->
+			let new_appliance = create ~__context:__context_to
+				~name_label:old_appliance.API.vM_appliance_name_label
+				~name_description:old_appliance.API.vM_appliance_name_description in
+			List.iter
+				(fun vm -> Db.VM.set_appliance ~__context:__context_to ~self:vm ~value:new_appliance)
+				recovered_vms;
+			try
+				Db.VM_appliance.set_uuid ~__context:__context_to
+					~self:new_appliance
+					~value:old_appliance.API.vM_appliance_uuid
+			with Db_exn.Uniqueness_constraint_violation(_, _, _) ->
+				(* Fail silently if the appliance's uuid already exists. *)
+				debug
+					"Could not give VM appliance the uuid %s as a VM appliance with this uuid already exists."
+					old_appliance.API.vM_appliance_uuid)

ocaml/xapi/xapi_vm_appliance.mli

@@ -17,3 +17,5 @@ val hard_shutdown :
 
 val assert_can_be_recovered :
 	__context:Context.t -> self:[ `VM_appliance ] Ref.t -> session_to:[ `session ] Ref.t -> unit
+val recover :
+	__context:Context.t -> self:[ `VM_appliance ] Ref.t -> session_to:[ `session ] Ref.t -> force:bool -> unit