Workaround for time.Duration zero value

Go 1.6 has the zero value of time.Duration render to a string as `0`,
but 1.7 and on renders as `0s`.

Force to `0s` for consistency across versions.

pkg/apis/kops/componentconfig.go

@@ -306,7 +306,7 @@ type KubeletConfigSpec struct {
 	// Comma-delimited list of grace periods for each soft eviction signal.  For example, 'memory.available=30s'.
 	EvictionSoftGracePeriod string `json:"evictionSoftGracePeriod,omitempty" flag:"eviction-soft-grace-period"`
 	// Duration for which the kubelet has to wait before transitioning out of an eviction pressure condition.
-	EvictionPressureTransitionPeriod metav1.Duration `json:"evictionPressureTransitionPeriod,omitempty" flag:"eviction-pressure-transition-period" flag-empty:"0"`
+	EvictionPressureTransitionPeriod metav1.Duration `json:"evictionPressureTransitionPeriod,omitempty" flag:"eviction-pressure-transition-period" flag-empty:"0s"`
 	// Maximum allowed grace period (in seconds) to use when terminating pods in response to a soft eviction threshold being met.
 	EvictionMaxPodGracePeriod int32 `json:"evictionMaxPodGracePeriod,omitempty" flag:"eviction-max-pod-grace-period" flag-empty:"0"`
 	// Comma-delimited list of minimum reclaims (e.g. imagefs.available=2Gi) that describes the minimum amount of resource the kubelet will reclaim when performing a pod eviction if that resource is under pressure.

pkg/flagbuilder/build_flags.go

@@ -114,6 +114,14 @@ func BuildFlags(options interface{}) (string, error) {
 
 		case metav1.Duration:
 			vString := v.Duration.String()
+
+			// See https://github.com/kubernetes/kubernetes/issues/40783
+			// Go renders a time.Duration to `0` in <= 1.6, and `0s` in >= 1.7
+			// We force it to be `0s`, regardless of value
+			if vString == "0" {
+				vString = "0s"
+			}
+
 			if vString != flagEmpty {
 				flag = fmt.Sprintf("--%s=%s", flagName, vString)
 			}