Add sleep before layer operation retries

dcantah · dcantah · commit adc35b064429 · 2021-08-18T16:05:28.000-07:00
This change adds a small sleep before a re-attempt on layer operation
failures. These failures should only happen on RS5 and the probable cause is because
of a different way in which container loopback vhds were mounted on this OS version.
A theory of why things might go awry on RS5 is due to some events from pnp getting reported
too late/early. If the prognosis is correct, a small sleep might help to try and get
things back into a "good" state before a reattempt.

Signed-off-by: Daniel Canter &lt;dcanter@microsoft.com&gt;
diff --git a/internal/layers/layers.go b/internal/layers/layers.go
@@ -8,6 +8,7 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"time"
 
 	hcsschema "github.com/Microsoft/hcsshim/internal/hcs/schema2"
 	"github.com/Microsoft/hcsshim/internal/hcserror"
@@ -115,6 +116,9 @@ func MountContainerLayers(ctx context.Context, containerId string, layerFolders
 				// for ERROR_NOT_READY as well.
 				if hcserr, ok := lErr.(*hcserror.HcsError); ok {
 					if hcserr.Err == windows.ERROR_NOT_READY || hcserr.Err == windows.ERROR_DEVICE_NOT_CONNECTED {
+						// Sleep for a little before a re-attempt. A probable cause for these issues in the first place is events not getting
+						// reported in time so might be good to give some time for things to "cool down" or get back to a known state.
+						time.Sleep(time.Millisecond * 100)
 						continue
 					}
 				}
