fix: always retry when port detection fails

When creating a zeropod with scaleDownDuration 0, it can happen that
the port detection fails due to the initialProcess not even existing
yet. In that case, we should return errNoPortsDetected so the caller can
retry later.

zeropod/container.go

@@ -276,11 +276,10 @@ func (c *Container) startActivator(ctx context.Context) error {
 		log.G(ctx).Info("no ports defined in config, detecting listening ports")
 		// if no ports are specified in the config, we try to find all listening ports
 		ports, err := listeningPortsDeep(c.initialProcess.Pid())
-		if err != nil {
-			return err
-		}
-
-		if len(ports) == 0 {
+		if err != nil || len(ports) == 0 {
+			// our initialProcess might not even be running yet, so finding the listening
+			// ports might fail in various ways. We return errNoPortsDetected so the
+			// caller can retry later.
 			return errNoPortsDetected
 		}