问允许变异的tls钩子使用启用tls的istio。
EN

Stack Overflow用户

提问于 2022-06-05 04:22:31

回答 3查看 589关注 0票数 6

我有下面的MutatingWebhookConfiguration

apiVersion: admissionregistration.k8s.io/v1
kind: MutatingWebhookConfiguration
metadata:
  name: example-webhook
webhooks:
  - name: example-webhook.default.svc.cluster.local
    admissionReviewVersions:
      - "v1beta1"
    sideEffects: "None"
    timeoutSeconds: 30
    objectSelector:
      matchLabels:
        example-webhook-enabled: "true"
    clientConfig:
      service:
        name: example-webhook
        namespace: default
        path: "/mutate"
      caBundle: "LS0tLS1CR..."
    rules:
      - operations: [ "CREATE" ]
        apiGroups: [""]
        apiVersions: ["v1"]
        resources: ["pods"]

我想将webhook pod注入一个启用了istio的命名空间中，istio具有严格的TLS模式。

因此，(我认为)在我的example-webhook服务中不应该需要TLS，因此它是按如下方式构建的：

apiVersion: v1
kind: Service
metadata:
  name: example-webhook
  namespace: default
spec:
  selector:
    app: example-webhook
  ports:
    - port: 80
      targetPort: webhook
      name: webhook

但是，当创建一个Pod (这确实会触发webhook)时，我会得到以下错误：

▶ k create -f demo-pod.yaml
Error from server (InternalError): error when creating "demo-pod.yaml": Internal error occurred: failed calling webhook "example-webhook.default.svc.cluster.local": Post "https://example-webhook.default.svc:443/mutate?timeout=30s": no service port 443 found for service "example-webhook"

我不能将web钩子配置为不是在443上调用，而是在80上调用吗？无论哪种方式，TLS终止都是由istio侧way完成的。

有没有办法用VirtualService / DestinationRule解决这个问题？

编辑：最重要的是，为什么它试图到达example-webhook.default.svc端点中的服务？(而它应该在example-webhook.default.svc.cluster.local中这样做)？

更新1

我试图按以下方式使用https：

我使用istio的CA创建了一个证书和私钥。

我可以验证我在证书中的DNS名称是否有效，如下所示(从另一个pod)

echo | openssl s_client -showcerts -servername example-webhook.default.svc -connect example-webhook.default.svc:443 2>/dev/null | openssl x509 -inform pem -noout -text

...
 Subject: C = GR, ST = Attica, L = Athens, O = Engineering, OU = FOO, CN = *.cluster.local, emailAddress = me@myemail.com
...
        X509v3 extensions:
            X509v3 Subject Alternative Name:
                DNS:*.default.svc.cluster.local, DNS:example-webhook, DNS:example-webhook.default.svc
...

但是现在pod的创建失败了，如下所示：

▶ k create -f demo-pod.yaml
Error from server (InternalError): error when creating "demo-pod.yaml": Internal error occurred: failed calling webhook "example-webhook.default.svc.cluster.local": Post "https://example-webhook.default.svc:443/mutate?timeout=30s": x509: certificate is not valid for any names, but wanted to match example-webhook.default.svc

更新2

使用istio CA证书适当地创建了运行webhook结荚的证书，这一事实也得到了验证。

curl --cacert istio_cert https://example-webhook.default.svc
Test

其中istio_cert是包含istio的CA证书的文件

怎么一回事？

tls1.2

istio

ssl

kubernetes

webhooks

回答 3

Stack Overflow用户

发布于 2022-06-06 03:14:52

不确定你能不能在端口80上使用web钩子..。

其中一些可能会对您有用，我使用了以下脚本来生成证书，您可以修改它以满足您的需要：

#!/bin/bash

set -e

service=webhook-svc
namespace=default
secret=webhook-certs
csrName=${service}.${namespace}

cat <<EOF >> csr.conf
[req]
req_extensions = v3_req
distinguished_name = req_distinguished_name
[req_distinguished_name]
[ v3_req ]
basicConstraints = CA:FALSE
keyUsage = nonRepudiation, digitalSignature, keyEncipherment
extendedKeyUsage = serverAuth
subjectAltName = @alt_names
[alt_names]
DNS.1 = ${service}
DNS.2 = ${service}.${namespace}
DNS.3 = ${service}.${namespace}.svc
EOF

openssl genrsa -out server-key.pem 2048
openssl req -new -key server-key.pem -subj "/CN=${service}.${namespace}.svc" -out server.csr -config csr.conf

kubectl delete csr ${csrName} 2>/dev/null || true

cat <<EOF | kubectl create -f -
apiVersion: certificates.k8s.io/v1beta1
kind: CertificateSigningRequest
metadata:
  name: ${csrName}
spec:
  groups:
  - system:authenticated
  request: $(< server.csr base64 | tr -d '\n')
  usages:
  - digital signature
  - key encipherment
  - server auth
EOF

sleep 5

kubectl certificate approve ${csrName}

for i in {1 .. 10}
do
    serverCert=$(kubectl get csr ${csrName} -o jsonpath='{.status.certificate}')
    if [[ ${serverCert} != '' ]]; then
        break
    fi
    sleep 1
done
if [[ ${serverCert} == '' ]]; then
    echo "ERROR: After approving csr ${csrName}, the signed certificate did not appear on the resource. Giving up after 10 attempts." >&2
    exit 1
fi


echo "${serverCert}" | openssl base64 -d -A -out server-cert.pem


# create the secret with CA cert and server cert/key
kubectl create secret generic ${secret} \
        --from-file=key.pem=server-key.pem \
        --from-file=cert.pem=server-cert.pem \
        --dry-run -o yaml |
    kubectl -n ${namespace} apply -f -

脚本创建了一个秘密，然后我将其挂载到web钩子deployment.yaml中：

apiVersion: apps/v1
kind: Deployment
metadata:
  name: webhook-deployment
  namespace: default
  labels:
    app: webhook
  annotations:
    sidecar.istio.io/inject: "false"
spec:
  replicas: 1
  selector:
    matchLabels:
      app: webhook
  template:
    metadata:
      labels:
        app: webhook
      annotations:
        sidecar.istio.io/inject: "false"
    spec:
      containers:
        - name: webhook
          image: webhook:v1
          imagePullPolicy: IfNotPresent
          volumeMounts:
          - name: webhook-certs
            mountPath: /certs
            readOnly: true
      volumes:
      - name: webhook-certs
        secret:
          secretName: webhook-certs

service.yaml：

apiVersion: v1
kind: Service
metadata:
  name: webhook-svc
  namespace: default
  labels:
    app: webhook
spec:
  ports:
  - port: 443
    targetPort: 8443
  selector:
    app: webhook

票数 1

Stack Overflow用户

发布于 2022-06-08 12:24:51

您是否尝试将端口属性添加到MutatingWebhookConfiguration中？

clientConfig:
      service:
        name: example-webhook
        namespace: default
        path: "/mutate"
        port: 80

票数 1

Stack Overflow用户

发布于 2022-06-13 20:32:10

您可以尝试更改值。

cat <<EOF | kubectl create -f -
apiVersion: certificates.k8s.io/v1beta1
kind: CertificateSigningRequest
metadata:
  name: ${csrName}
spec:
  groups:
  - system:authenticated
  request: $(< server.csr base64 | tr -d '\n')
  usages:
  - digital signature
  - key encipherment
  - server auth
EOF