node: device-mgr: Add logs in the happy path

We have reasonable amount of logs when things go wrong.
While debugging, it can be useful to have logs to indicate that
things have gone as expected.

Signed-off-by: Swati Sehgal <swsehgal@redhat.com>

pkg/kubelet/cm/devicemanager/manager.go

@@ -506,6 +506,7 @@ func (m *ManagerImpl) writeCheckpoint() error {
 		klog.ErrorS(err, "Failed to write checkpoint file")
 		return err2
 	}
+	klog.V(4).InfoS("checkpoint file written", "checkpoint", kubeletDeviceManagerCheckpoint)
 	return nil
 }
 
@@ -534,6 +535,8 @@ func (m *ManagerImpl) readCheckpoint() error {
 		m.unhealthyDevices[resource] = sets.New[string]()
 		m.endpoints[resource] = endpointInfo{e: newStoppedEndpointImpl(resource), opts: nil}
 	}
+
+	klog.V(4).InfoS("read data from checkpoint file", "checkpoint", kubeletDeviceManagerCheckpoint)
 	return nil
 }
 

pkg/kubelet/cm/devicemanager/plugin/v1beta1/client.go

@@ -106,6 +106,8 @@ func (c *client) Disconnect() error {
 	}
 	c.mutex.Unlock()
 	c.handler.PluginDisconnected(c.resource)
+
+	klog.V(2).InfoS("device plugin disconnected", "resource", c.resource)
 	return nil
 }
 

pkg/kubelet/cm/devicemanager/plugin/v1beta1/handler.go

@@ -62,6 +62,7 @@ func (s *server) ValidatePlugin(pluginName string, endpoint string, versions []s
 		return fmt.Errorf("invalid name of device plugin socket: %s", fmt.Sprintf(errInvalidResourceName, pluginName))
 	}
 
+	klog.V(2).InfoS("plugin validated", "plugin", pluginName, "endpoint", endpoint, "versions", versions)
 	return nil
 }
 
@@ -75,6 +76,7 @@ func (s *server) connectClient(name string, socketPath string) error {
 		return err
 	}
 
+	klog.V(2).InfoS("Connected to new client", "resource", name)
 	go func() {
 		s.runClient(name, c)
 	}()

pkg/kubelet/cm/devicemanager/plugin/v1beta1/server.go

@@ -145,6 +145,7 @@ func (s *server) Stop() error {
 	// During kubelet termination, we do not need the registration server,
 	// and we consider the kubelet to be healthy even when it is down.
 	s.setHealthy()
+	klog.V(2).InfoS("Stopping device plugin registration server")
 
 	return nil
 }