Merge pull request #55976 from caesarxuchao/move-mutating-to-last

Automatic merge from submit-queue (batch tested with PRs 51321, 55969, 55039, 56183, 55976). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

Move mutating to run last in the mutating admission plugin chain

ref: kubernetes/features#492

Follow up on #54892. (see https://github.com/kubernetes/kubernetes/pull/54892#discussion_r151333585)

Only the last commit is relevant.

The reasons are:
* Mutating webhooks are dynamic, they can always adjust according to the behavior of compiled-in admission plugins, but not the other-way around.
* We'll document that if user deploys mutating webhooks that over some built-in mutating plugins decision, user needs also to disable the built-in validating plugins, otherwise the cluster might block.
This commit is contained in:
Kubernetes Submit Queue 2017-11-22 12:00:01 -08:00 committed by GitHub
commit f8ffbd9d61
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4 changed files with 15 additions and 9 deletions

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@ -316,12 +316,12 @@ if [[ -n "${GCE_GLBC_IMAGE:-}" ]]; then
fi
if [[ -z "${KUBE_ADMISSION_CONTROL:-}" ]]; then
ADMISSION_CONTROL="MutatingAdmissionWebhook,Initializers,NamespaceLifecycle,LimitRanger,ServiceAccount,PersistentVolumeLabel,PodPreset,DefaultStorageClass,DefaultTolerationSeconds,NodeRestriction,Priority"
ADMISSION_CONTROL="Initializers,NamespaceLifecycle,LimitRanger,ServiceAccount,PersistentVolumeLabel,PodPreset,DefaultStorageClass,DefaultTolerationSeconds,NodeRestriction,Priority"
if [[ "${ENABLE_POD_SECURITY_POLICY:-}" == "true" ]]; then
ADMISSION_CONTROL="${ADMISSION_CONTROL},PodSecurityPolicy"
fi
# ResourceQuota must come last, or a creation is recorded, but the pod may be forbidden.
ADMISSION_CONTROL="${ADMISSION_CONTROL},ValidatingAdmissionWebhook,ResourceQuota"
ADMISSION_CONTROL="${ADMISSION_CONTROL},MutatingAdmissionWebhook,ValidatingAdmissionWebhook,ResourceQuota"
else
ADMISSION_CONTROL=${KUBE_ADMISSION_CONTROL}
fi

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@ -104,8 +104,8 @@ func TestAddFlags(t *testing.T) {
MinRequestTimeout: 1800,
},
Admission: &apiserveroptions.AdmissionOptions{
RecommendedPluginOrder: []string{"MutatingAdmissionWebhook", "NamespaceLifecycle", "Initializers", "ValidatingAdmissionWebhook"},
DefaultOffPlugins: []string{"MutatingAdmissionWebhook", "Initializers", "ValidatingAdmissionWebhook"},
RecommendedPluginOrder: []string{"NamespaceLifecycle", "Initializers", "MutatingAdmissionWebhook", "ValidatingAdmissionWebhook"},
DefaultOffPlugins: []string{"Initializers", "MutatingAdmissionWebhook", "ValidatingAdmissionWebhook"},
PluginNames: []string{"AlwaysDeny"},
ConfigFile: "/admission-control-config",
Plugins: s.Admission.Plugins,

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@ -419,7 +419,9 @@ function start_apiserver {
fi
# Admission Controllers to invoke prior to persisting objects in cluster
ADMISSION_CONTROL=MutatingAdmissionWebhook,Initializers,NamespaceLifecycle,LimitRanger,ServiceAccount${security_admission},DefaultStorageClass,DefaultTolerationSeconds,ValidatingAdmissionWebhook,ResourceQuota
#
# ResourceQuota must come last, or a creation is recorded, but the pod may be forbidden.
ADMISSION_CONTROL=Initializers,NamespaceLifecycle,LimitRanger,ServiceAccount${security_admission},DefaultStorageClass,DefaultTolerationSeconds,MutatingAdmissionWebhook,ValidatingAdmissionWebhook,ResourceQuota
# This is the default dir and filename where the apiserver will generate a self-signed cert
# which should be able to be used as the CA to verify itself

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@ -59,10 +59,14 @@ type AdmissionOptions struct {
// Servers that do care can overwrite/append that field after creation.
func NewAdmissionOptions() *AdmissionOptions {
options := &AdmissionOptions{
Plugins: admission.NewPlugins(),
PluginNames: []string{},
RecommendedPluginOrder: []string{mutatingwebhook.PluginName, lifecycle.PluginName, initialization.PluginName, validatingwebhook.PluginName},
DefaultOffPlugins: []string{mutatingwebhook.PluginName, initialization.PluginName, validatingwebhook.PluginName},
Plugins: admission.NewPlugins(),
PluginNames: []string{},
// This list is mix of mutating admission plugins and validating
// admission plugins. The apiserver always runs the validating ones
// after all the mutating ones, so their relative order in this list
// doesn't matter.
RecommendedPluginOrder: []string{lifecycle.PluginName, initialization.PluginName, mutatingwebhook.PluginName, validatingwebhook.PluginName},
DefaultOffPlugins: []string{initialization.PluginName, mutatingwebhook.PluginName, validatingwebhook.PluginName},
}
apiserverapi.AddToScheme(options.Plugins.ConfigScheme)
apiserverapiv1alpha1.AddToScheme(options.Plugins.ConfigScheme)