CNI Delete to ignore network not found error (#1293)

* not to return error for network not found in delete call

* added comments

Author: tamilmani1989

cni/network/network.go

@@ -976,21 +976,14 @@ func (plugin *NetPlugin) Delete(args *cniSkel.CmdArgs) error {
 
 	// Query the network.
 	if nwInfo, err = plugin.nm.GetNetworkInfo(networkID); err != nil {
-
 		if !nwCfg.MultiTenancy {
-			// attempt to release address associated with this Endpoint id
-			// This is to ensure clean up is done even in failure cases
-			log.Errorf("[cni-net] Failed to query network: %v", err)
-			telemetry.LogAndSendEvent(plugin.tb, fmt.Sprintf("Release ip by ContainerID (network not found):%v", args.ContainerID))
-			err = plugin.ipamInvoker.Delete(nil, nwCfg, args, nwInfo.Options)
-			if err != nil {
-				return plugin.RetriableError(fmt.Errorf("failed to release address(no network): %w", err))
-			}
+			log.Printf("[cni-net] Failed to query network: %v", err)
+			// Log the error but return success if the network is not found.
+			// if cni hits this, mostly state file would be missing and it can be reboot scenario where
+			// container runtime tries to delete and create pods which existed before reboot.
+			err = nil
+			return err
 		}
-
-		// Log the error but return success if the endpoint being deleted is not found.
-		err = nil
-		return err
 	}
 
 	endpointID := GetEndpointID(args)