diff --git a/virtcontainers/agent.go b/virtcontainers/agent.go
index 2a0acc457a..a25e4d4843 100644
--- a/virtcontainers/agent.go
+++ b/virtcontainers/agent.go
@@ -172,4 +172,8 @@ type agent interface {
 
 	// processListContainer will list the processes running inside the container
 	processListContainer(pod Pod, c Container, options ProcessListOptions) (ProcessList, error)
+
+	// onlineCPUMem will online CPUs and Memory inside the Pod.
+	// This function should be called after hot adding vCPUs or Memory.
+	onlineCPUMem() error
 }
diff --git a/virtcontainers/container.go b/virtcontainers/container.go
index 87ea329dfa..47380131b3 100644
--- a/virtcontainers/container.go
+++ b/virtcontainers/container.go
@@ -787,6 +787,8 @@ func (c *Container) addResources() error {
 		if err := c.pod.hypervisor.hotplugAddDevice(uint32(vCPUs), cpuDev); err != nil {
 			return err
 		}
+
+		return c.pod.agent.onlineCPUMem()
 	}
 
 	return nil
diff --git a/virtcontainers/hyperstart_agent.go b/virtcontainers/hyperstart_agent.go
index 4f0e487ffc..73b3cac688 100644
--- a/virtcontainers/hyperstart_agent.go
+++ b/virtcontainers/hyperstart_agent.go
@@ -794,3 +794,8 @@ func (h *hyper) sendCmd(proxyCmd hyperstartProxyCmd) (interface{}, error) {
 
 	return h.client.HyperWithTokens(proxyCmd.cmd, tokens, proxyCmd.message)
 }
+
+func (h *hyper) onlineCPUMem() error {
+	// cc-agent uses udev to online CPUs automatically
+	return nil
+}
diff --git a/virtcontainers/kata_agent.go b/virtcontainers/kata_agent.go
index 329e576cfa..1350f69f90 100644
--- a/virtcontainers/kata_agent.go
+++ b/virtcontainers/kata_agent.go
@@ -773,6 +773,13 @@ func (k *kataAgent) processListContainer(pod Pod, c Container, options ProcessLi
 	return nil, nil
 }
 
+func (k *kataAgent) onlineCPUMem() error {
+	req := &grpc.OnlineCPUMemRequest{}
+
+	_, err := k.sendReq(req)
+	return err
+}
+
 func (k *kataAgent) connect() error {
 	if k.client != nil {
 		return nil
@@ -836,6 +843,8 @@ func (k *kataAgent) sendReq(request interface{}) (interface{}, error) {
 	case *grpc.UpdateInterfaceRequest:
 		ifc, err := k.client.UpdateInterface(context.Background(), req)
 		return ifc, err
+	case *grpc.OnlineCPUMemRequest:
+		return k.client.OnlineCPUMem(context.Background(), req)
 	default:
 		return nil, fmt.Errorf("Unknown gRPC type %T", req)
 	}
diff --git a/virtcontainers/noop_agent.go b/virtcontainers/noop_agent.go
index 136831fc04..13d7a2e78d 100644
--- a/virtcontainers/noop_agent.go
+++ b/virtcontainers/noop_agent.go
@@ -79,3 +79,8 @@ func (n *noopAgent) killContainer(pod Pod, c Container, signal syscall.Signal, a
 func (n *noopAgent) processListContainer(pod Pod, c Container, options ProcessListOptions) (ProcessList, error) {
 	return nil, nil
 }
+
+// onlineCPUMem is the Noop agent Container online CPU and Memory implementation. It does nothing.
+func (n *noopAgent) onlineCPUMem() error {
+	return nil
+}