Remove alpha InitializerConfiguration types, Initializers admission plugin

hack/.golint_failures

@@ -15,7 +15,6 @@ pkg/apis/abac/latest
 pkg/apis/admission
 pkg/apis/admission/v1beta1
 pkg/apis/admissionregistration
-pkg/apis/admissionregistration/v1alpha1
 pkg/apis/admissionregistration/v1beta1
 pkg/apis/admissionregistration/validation
 pkg/apis/apps
@@ -254,7 +253,6 @@ pkg/proxy/util
 pkg/proxy/winkernel
 pkg/proxy/winuserspace
 pkg/quota/v1/evaluator/core
-pkg/registry/admissionregistration/initializerconfiguration/storage
 pkg/registry/admissionregistration/mutatingwebhookconfiguration/storage
 pkg/registry/admissionregistration/rest
 pkg/registry/admissionregistration/validatingwebhookconfiguration/storage
@@ -423,7 +421,6 @@ plugin/pkg/auth/authorizer/node
 plugin/pkg/auth/authorizer/rbac
 plugin/pkg/auth/authorizer/rbac/bootstrappolicy
 staging/src/k8s.io/api/admission/v1beta1
-staging/src/k8s.io/api/admissionregistration/v1alpha1
 staging/src/k8s.io/api/admissionregistration/v1beta1
 staging/src/k8s.io/api/apps/v1
 staging/src/k8s.io/api/apps/v1beta1
@@ -520,7 +517,6 @@ staging/src/k8s.io/apimachinery/pkg/watch
 staging/src/k8s.io/apiserver/pkg/admission
 staging/src/k8s.io/apiserver/pkg/admission/configuration
 staging/src/k8s.io/apiserver/pkg/admission/initializer
-staging/src/k8s.io/apiserver/pkg/admission/plugin/initialization
 staging/src/k8s.io/apiserver/pkg/admission/plugin/webhook/config/apis/webhookadmission
 staging/src/k8s.io/apiserver/pkg/admission/plugin/webhook/config/apis/webhookadmission/v1alpha1
 staging/src/k8s.io/apiserver/pkg/admission/plugin/webhook/testcerts

hack/lib/init.sh

@@ -56,7 +56,6 @@ KUBE_OUTPUT_HOSTBIN="${KUBE_OUTPUT_BINPATH}/$(kube::util::host_platform)"
 # most preferred version for a group should appear first
 KUBE_AVAILABLE_GROUP_VERSIONS="${KUBE_AVAILABLE_GROUP_VERSIONS:-\
 v1 \
-admissionregistration.k8s.io/v1alpha1 \
 admissionregistration.k8s.io/v1beta1 \
 admission.k8s.io/v1beta1 \
 apps/v1 \

hack/local-up-cluster.sh

@@ -522,13 +522,6 @@ function start_apiserver {
       priv_arg="--allow-privileged=${ALLOW_PRIVILEGED} "
     fi
 
-    if [[ ${ENABLE_ADMISSION_PLUGINS} == *"Initializers"* ]]; then
-        if [[ -n "${RUNTIME_CONFIG}" ]]; then
-          RUNTIME_CONFIG+=","
-        fi
-        RUNTIME_CONFIG+="admissionregistration.k8s.io/v1alpha1"
-    fi
-
     runtime_config=""
     if [[ -n "${RUNTIME_CONFIG}" ]]; then
       runtime_config="--runtime-config=${RUNTIME_CONFIG}"

hack/update-generated-protobuf-dockerized.sh

@@ -76,7 +76,6 @@ PACKAGES=(
   k8s.io/api/storage/v1alpha1
   k8s.io/api/storage/v1beta1
   k8s.io/api/storage/v1
-  k8s.io/api/admissionregistration/v1alpha1
   k8s.io/api/admissionregistration/v1beta1
   k8s.io/api/admission/v1beta1
   k8s.io/api/auditregistration/v1alpha1