Merge pull request kubernetes-sigs#753 from maqiuyujoyce/202506-reduce-noise

Stopping logging error when the connection no longer exists

(cherry picked from commit 164763c)

Author: k8s-ci-robot

pkg/agent/client.go

@@ -354,7 +354,13 @@ func (a *Client) Serve() {
 			if status.Code(err) == codes.Canceled {
 				klog.V(2).InfoS("stream canceled", "serverID", a.serverID, "agentID", a.agentID)
 			} else {
-				klog.ErrorS(err, "could not read stream", "serverID", a.serverID, "agentID", a.agentID)
+				select {
+				case <-a.stopCh:
+					klog.V(5).InfoS("could not read stream because agent client is shutting down", "serverID", a.serverID, "agentID", a.agentID, "err", err)
+				default:
+					// If stopCh is not closed, this is a legitimate, unexpected error.
+					klog.ErrorS(err, "could not read stream", "serverID", a.serverID, "agentID", a.agentID)
+				}
 			}
 			return
 		}
@@ -407,7 +413,13 @@ func (a *Client) Serve() {
 					closePkt.GetCloseResponse().ConnectID = connID
 				}
 				if err := a.Send(closePkt); err != nil {
-					klog.ErrorS(err, "close response failure", "")
+					if err == io.EOF {
+						klog.V(4).InfoS("received EOF; connection already closed", "connectionID", connID, "dialID", dialReq.Random, "err", err)
+					} else if _, ok := a.connManager.Get(connID); !ok {
+						klog.V(5).InfoS("connection already closed", "connectionID", connID, "dialID", dialReq.Random, "err", err)
+					} else {
+						klog.ErrorS(err, "close response failure", "connectionID", connID, "dialID", dialReq.Random)
+					}
 				}
 				close(dataCh)
 				a.connManager.Delete(connID)