Merge pull request #9882 from masayag/support_decreasing_memory_in_re…

…configure_vm

Update Guaranteed memory when updating VM's memory
(cherry picked from commit 7270d7d)

app/models/manageiq/providers/redhat/infra_manager.rb

@@ -218,7 +218,7 @@ def vm_reconfigure(vm, options = {})
 
     vm.with_provider_object do |rhevm_vm|
       _log.info("#{log_header} Started...")
-      rhevm_vm.memory = spec["memoryMB"] * 1.megabyte   if spec["memoryMB"]
+      update_vm_memory(rhevm_vm, spec["memoryMB"] * 1.megabyte) if spec["memoryMB"]
 
       cpu_options = {}
       cpu_options[:cores]   = spec["numCoresPerSocket"] if spec["numCoresPerSocket"]
@@ -229,6 +229,19 @@ def vm_reconfigure(vm, options = {})
     _log.info("#{log_header} Completed.")
   end
 
+  # RHEVM requires that the memory of the VM will be bigger or equal to the reserved memory at any given time.
+  # Therefore, increasing the memory of the vm should precede to updating the reserved memory, and the opposite:
+  # Decreasing the memory to a lower value than the reserved memory requires first to update the reserved memory
+  def update_vm_memory(rhevm_vm, memory)
+    if memory > rhevm_vm.attributes.fetch_path(:memory)
+      rhevm_vm.memory = memory
+      rhevm_vm.memory_reserve = memory
+    else
+      rhevm_vm.memory_reserve = memory
+      rhevm_vm.memory = memory
+    end
+  end
+
   # Calculates an "ems_ref" from the "href" attribute provided by the oVirt REST API, removing the
   # "/ovirt-engine/" prefix, as for historic reasons the "ems_ref" stored in the database does not
   # contain it, it only contains the "/api" prefix which was used by older versions of the engine.

spec/models/manageiq/providers/redhat/infra_manager_spec.rb

@@ -35,22 +35,31 @@
       @num_of_sockets   = 3
       @total_mem_in_mb  = 4096
 
-      @spec             = {"memoryMB"          => @total_mem_in_mb,
-                           "numCPUs"           => @cores_per_socket * @num_of_sockets,
-                           "numCoresPerSocket" => @cores_per_socket}
-
-      @rhevm_vm = double('rhevm_vm').as_null_object
+      @rhevm_vm_attrs = double('rhevm_vm_attrs')
+      allow(@rhevm_vm_attrs).to receive(:fetch_path).with(:memory).and_return(@total_mem_in_mb.megabytes)
+      @rhevm_vm = double('rhevm_vm')
+      allow(@rhevm_vm).to receive(:attributes).and_return(@rhevm_vm_attrs)
       allow(@vm).to receive(:with_provider_object).and_yield(@rhevm_vm)
     end
 
     it "cpu_topology=" do
+      spec = {
+        "numCPUs"           => @cores_per_socket * @num_of_sockets,
+        "numCoresPerSocket" => @cores_per_socket
+      }
+
       expect(@rhevm_vm).to receive(:cpu_topology=).with(:cores => @cores_per_socket, :sockets => @num_of_sockets)
-      @ems.vm_reconfigure(@vm, :spec => @spec)
+      @ems.vm_reconfigure(@vm, :spec => spec)
     end
 
     it "memory=" do
+      spec = {
+        "memoryMB" => @total_mem_in_mb
+      }
+
       expect(@rhevm_vm).to receive(:memory=).with(@total_mem_in_mb.megabytes)
-      @ems.vm_reconfigure(@vm, :spec => @spec)
+      expect(@rhevm_vm).to receive(:memory_reserve=).with(@total_mem_in_mb.megabytes)
+      @ems.vm_reconfigure(@vm, :spec => spec)
     end
   end