Add --plugins flag to velero install (#1930)

* Add plugins flag to install

Signed-off-by: Nolan Brubaker <brubakern@vmware.com>

pkg/install/deployment.go

@@ -24,6 +24,8 @@ import (
 	appsv1 "k8s.io/api/apps/v1"
 	corev1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+
+	"github.com/vmware-tanzu/velero/pkg/builder"
 )
 
 type podTemplateOption func(*podTemplateConfig)
@@ -36,6 +38,7 @@ type podTemplateConfig struct {
 	resources                         corev1.ResourceRequirements
 	withSecret                        bool
 	defaultResticMaintenanceFrequency time.Duration
+	plugins                           []string
 }
 
 func WithImage(image string) podTemplateOption {
@@ -91,6 +94,12 @@ func WithDefaultResticMaintenanceFrequency(val time.Duration) podTemplateOption
 	}
 }
 
+func WithPlugins(plugins []string) podTemplateOption {
+	return func(c *podTemplateConfig) {
+		c.plugins = plugins
+	}
+}
+
 func Deployment(namespace string, opts ...podTemplateOption) *appsv1.Deployment {
 	// TODO: Add support for server args
 	c := &podTemplateConfig{
@@ -236,5 +245,13 @@ func Deployment(namespace string, opts ...podTemplateOption) *appsv1.Deployment
 		deployment.Spec.Template.Spec.Containers[0].Args = append(deployment.Spec.Template.Spec.Containers[0].Args, fmt.Sprintf("--default-restic-prune-frequency=%v", c.defaultResticMaintenanceFrequency))
 	}
 
+	if len(c.plugins) > 0 {
+		for _, image := range c.plugins {
+			container := *builder.ForPluginContainer(image, pullPolicy).Result()
+			deployment.Spec.Template.Spec.InitContainers = append(deployment.Spec.Template.Spec.InitContainers, container)
+		}
+
+	}
+
 	return deployment
 }