配置验证 Webhook
- 看似正确的配置被拒绝
- 无效的配置被接受
- 创建配置失败并提示 x509 证书错误
- 创建配置失败，提示 no such hosts 或 no endpoints available 错误

配置验证 Webhook

Galley 配置验证确保用户授权的 Istio 配置在语法和语义上都是有效的。Galley 使用 Kubernetes ValidatingWebhook。 istio-galley ValidationWebhookConfiguration 有两个 webhook。

pilot.validation.istio.io - 服务地址路径为 /admitpilot，负责验证 Pilot 使用的配置（例如 VirtualService 、Authentication）。
mixer.validation.istio.io - 服务地址路径为 /admitmixer，负责验证 Mixer 使用的配置。

两个 webhook 都是在 istio-galley 服务的 443 端口上提供服务。每个 webhook 都有自己的 clientConfig 、 namespaceSelector 和 rules 部分。这两个 webhook 都适用于所有的命名空间。 namespaceSelector 应该设置为空。两个规则都适用于 Istio CRD。

看似正确的配置被拒绝

手动验证配置是否正确，必要时参考 Istio API reference。

无效的配置被接受

验证 istio-galley validationwebhookconfiguration 配置存在并正确。 apiVersion 、apiGroup 和 resource 无效配置的资源应会在两个 webhooks 之一的条目中被列出。

$ kubectl get validatingwebhookconfiguration istio-galley -o yaml
apiVersion: admissionregistration.k8s.io/v1beta1
kind: ValidatingWebhookConfiguration
metadata:
  labels:
    app: istio-galley
  name: istio-galley
  ownerReferences:
  - apiVersion: extensions/v1beta1
    blockOwnerDeletion: true
    controller: true
    kind: Deployment
    name: istio-galley
    uid: 5c64585d-91c6-11e8-a98a-42010a8001a8
webhooks:
- clientConfig:
    # caBundle should be non-empty. This is periodically (re)patched
    # every second by the webhook service using the ca-cert
    # from the mounted service account secret.
    caBundle: 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
    service:
      # service corresponds to the Kubernetes service that implements the
      # webhook, e.g. istio-galley.istio-system.svc:443
      name: istio-galley
      namespace: istio-system
      path: /admitpilot
  failurePolicy: Fail
  name: pilot.validation.istio.io
  namespaceSelector: {}
  rules:
  - apiGroups:
    - config.istio.io
    apiVersions:
    - v1alpha2
    operations:
    - CREATE
    - UPDATE
    resources:
    - httpapispecs
    - httpapispecbindings
    - quotaspecs
    - quotaspecbindings
  - apiGroups:
    - rbac.istio.io
    apiVersions:
    - '*'
    operations:
    - CREATE
    - UPDATE
    resources:
    - '*'
  - apiGroups:
    - authentication.istio.io
    apiVersions:
    - '*'
    operations:
    - CREATE
    - UPDATE
    resources:
    - '*'
  - apiGroups:
    - networking.istio.io
    apiVersions:
    - '*'
    operations:
    - CREATE
    - UPDATE
    resources:
    - destinationrules
    - envoyfilters
    - gateways
    - virtualservices
- clientConfig:
    # caBundle should be non-empty. This is periodically (re)patched
    # every second by the webhook service using the ca-cert
    # from the mounted service account secret.
    caBundle: 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
    service:
      # service corresponds to the Kubernetes service that implements the
      # webhook, e.g. istio-galley.istio-system.svc:443
      name: istio-galley
      namespace: istio-system
      path: /admitmixer
  failurePolicy: Fail
  name: mixer.validation.istio.io
  namespaceSelector: {}
  rules:
  - apiGroups:
    - config.istio.io
    apiVersions:
    - v1alpha2
    operations:
    - CREATE
    - UPDATE
    resources:
    - rules
    - attributemanifests
    - circonuses
    - deniers
    - fluentds
    - kubernetesenvs
    - listcheckers
    - memquotas
    - noops
    - opas
    - prometheuses
    - rbacs
    - servicecontrols
    - solarwindses
    - stackdrivers
    - statsds
    - stdios
    - apikeys
    - authorizations
    - checknothings
    - listentries
    - logentries
    - metrics
    - quotas
    - reportnothings
    - servicecontrolreports
    - tracespans

如 validatingwebhookconfiguration 不存在，则需要验证 istio-galley-configuration configmap 是否存在。istio-galley 使用此 configmap 中的数据来创建和更新 validatingwebhookconfiguration。

$ kubectl -n istio-system get configmap istio-galley-configuration -o jsonpath='{.data}'
map[validatingwebhookconfiguration.yaml:apiVersion: admissionregistration.k8s.io/v1beta1
kind: ValidatingWebhookConfiguration
metadata:
  name: istio-galley
  namespace: istio-system
  labels:
    app: istio-galley
    chart: galley-1.0.0
    release: istio
    heritage: Tiller
webhooks:
  - name: pilot.validation.istio.io
    clientConfig:
      service:
        name: istio-galley
        namespace: istio-system
        path: "/admitpilot"
      caBundle: ""
    rules:
      - operations:
      (... snip ...)

如果 istio-galley-configuration 中的 webhook 数组为空，且是使用的是 helm template 或 helm install 的方式，请验证 —set galley.enabled 和 —set global.configValidation=true 选项是否已经设置。如果并使用 helm 的方式，则需要找到生成的 YAML，其中包含填充的 webhook 数组。

istio-galley 验证配置是失效关闭（fail-close）的。如果配置存在且范围正确，则 webhook 将被调用。在资源创建/更新时，如缺少 caBundle，错误证书或网络连接问题则会导致错误产生。如果 webhook 配置正确且没有发现任何错误提示，但是 webhook 未被调用，则表明群集配置存在错误。

创建配置失败并提示 x509 证书错误

x509: certificate signed by unknown authority 相关的错误通常由 webhook 配置中 caBundle 为空引起。验证它是否为空（请参阅验证 webhook 配置)。istio-galley 部署可动态使用保存在 istio-galley-configuration configmap 中的 webhook 配置和根证书会从 istio-system 命名空间中保存的 istio.istio-galley-service-account 密钥中加载。

验证 istio-galley pod 正在运行：

$  kubectl -n istio-system get pod -listio=galley
NAME                            READY     STATUS    RESTARTS   AGE
istio-galley-5dbbbdb746-d676g   1/1       Running   0          2d

确认使用的是 Istio 版本 >= 1.0.0。旧版本的 Galley 不能正确地 re-patch caBundle。这种情况通常发生在重新部署 istio.yaml 时，需要覆盖之前 patch 过的 caBundle。

$ for pod in $(kubectl -n istio-system get pod -listio=galley -o jsonpath='{.items[*].metadata.name}'); do \
    kubectl -n istio-system exec ${pod} -it /usr/local/bin/galley version| grep ^Version; \
done
Version: 1.0.0

检查 Galley pod 日志是否存在错误。Patch caBundle 失败则会打印相关错误。

$ for pod in $(kubectl -n istio-system get pod -listio=galley -o jsonpath='{.items[*].metadata.name}'); do \
    kubectl -n istio-system logs ${pod} \
done

如果 patch 失败，则需验证 Galley 的 RBAC 配置：

$ kubectl get clusterrole istio-galley-istio-system -o yaml
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  labels:
    app: istio-galley
  name: istio-galley-istio-system
rules:
- apiGroups:
  - admissionregistration.k8s.io
  resources:
  - validatingwebhookconfigurations
  verbs:
  - '*'
- apiGroups:
  - config.istio.io
  resources:
  - '*'
  verbs:
  - get
  - list
  - watch
- apiGroups:
  - '*'
  resourceNames:
  - istio-galley
  resources:
  - deployments
  verbs:
  - get

istio-galley 需对于 validatingwebhookconfigurations 写访问权以创建和更新 istio-galley validatingwebhook 配置。

创建配置失败，提示 no such hosts 或 no endpoints available 错误

验证是失败关闭的（fail-close）。如果 istio-galley pod 没有准备好，则无法创建和更新相关配置。这种情况下，会提示如下错误： no such host （Kubernetes 1.9）或 no endpoints available （>=1.10）的错误。

验证 istio-galley pod 正在运行且 endpoint 已准备就绪。

$  kubectl -n istio-system get pod -listio=galley
NAME                            READY     STATUS    RESTARTS   AGE
istio-galley-5dbbbdb746-d676g   1/1       Running   0          2d

$ kubectl -n istio-system get endpoints istio-galley
NAME           ENDPOINTS                          AGE
istio-galley   10.48.6.108:10514,10.48.6.108:443   3d

如果 pod 或 endpoint 尚未就绪，请检查 pod 日志和状态，以获取有关 webhook pod 无法启动和提供流量的原因。

$ for pod in $(kubectl -n istio-system get pod -listio=galley -o jsonpath='{.items[*].metadata.name}'); do \
    kubectl -n istio-system logs ${pod} \
done

$ for pod in $(kubectl -n istio-system get pod -listio=galley -o name); do \
    kubectl -n istio-system describe ${pod} \
done