1 files changed, 121 insertions, 0 deletions
diff --git a/tools/k8s/cluster-deployment/k8scluster/roles/clustermanager/files/danm-webhook-create-signed-cert.sh b/tools/k8s/cluster-deployment/k8scluster/roles/clustermanager/files/danm-webhook-create-signed-cert.sh
new file mode 100755
index 00000000..d1486f62
--- /dev/null
+++ b/tools/k8s/cluster-deployment/k8scluster/roles/clustermanager/files/danm-webhook-create-signed-cert.sh
@@ -0,0 +1,121 @@
+#!/bin/sh
+
+set -e
+
+usage() {
+    cat <<EOF
+Generate certificate suitable for use with an sidecar-injector webhook service.
+This script uses k8s' CertificateSigningRequest API to a generate a
+certificate signed by k8s CA suitable for use with sidecar-injector webhook
+services. This requires permissions to create and approve CSR. See
+https://kubernetes.io/docs/tasks/tls/managing-tls-in-a-cluster for
+detailed explantion and additional instructions.
+The server key/cert k8s CA cert are stored in a k8s secret.
+usage: ${0} [OPTIONS]
+The following flags are required.
+       --service          Service name of webhook.
+       --namespace        Namespace where webhook service and secret reside.
+       --secret           Secret name for CA certificate and server certificate/key pair.
+EOF
+    exit 1
+}
+
+while [ $# -gt 0 ]; do
+    case ${1} in
+        --service)
+            service="$2"
+            shift
+            ;;
+        --secret)
+            secret="$2"
+            shift
+            ;;
+        --namespace)
+            namespace="$2"
+            shift
+            ;;
+        *)
+            usage
+            ;;
+    esac
+    shift
+done
+
+[ -z ${service} ] && service=danm-webhook-svc
+[ -z ${secret} ] && secret=danm-webhook-certs
+[ -z ${namespace} ] && namespace=kube-system
+
+if [ ! -x "$(command -v openssl)" ]; then
+    echo "openssl not found"
+    exit 1
+fi
+
+csrName=${service}.${namespace}
+tmpdir=$(mktemp -d)
+echo "creating certs in tmpdir ${tmpdir} "
+
+cat <<EOF >> ${tmpdir}/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 ${tmpdir}/server-key.pem 2048
+openssl req -new -key ${tmpdir}/server-key.pem -subj "/CN=${service}.${namespace}.svc" -out ${tmpdir}/server.csr -config ${tmpdir}/csr.conf
+
+# clean-up any previously created CSR for our service. Ignore errors if not present.
+kubectl delete csr ${csrName} 2>/dev/null || true
+
+# create  server cert/key CSR and  send to k8s API
+cat <<EOF | kubectl create -f -
+apiVersion: certificates.k8s.io/v1beta1
+kind: CertificateSigningRequest
+metadata:
+  name: ${csrName}
+spec:
+  groups:
+  - system:authenticated
+  request: $(cat ${tmpdir}/server.csr | base64 | tr -d '\n')
+  usages:
+  - digital signature
+  - key encipherment
+  - server auth
+EOF
+
+# verify CSR has been created
+while true; do
+    kubectl get csr ${csrName}
+    if [ "$?" -eq 0 ]; then
+        break
+    fi
+done
+
+# approve and fetch the signed certificate
+kubectl certificate approve ${csrName}
+# verify certificate has been signed
+for x in $(seq 10); do
+    serverCert=$(kubectl get csr ${csrName} -o jsonpath='{.status.certificate}')
+    if [ -n ${serverCert} ]; then
+        break
+    fi
+    sleep 1
+done
+echo ${serverCert} | openssl base64 -d -A -out ${tmpdir}/server-cert.pem
+
+
+# create the secret with CA cert and server cert/key
+kubectl create secret generic ${secret} \
+        --from-file=key.pem=${tmpdir}/server-key.pem \
+        --from-file=cert.pem=${tmpdir}/server-cert.pem \
+        --dry-run -o yaml |
+    kubectl -n ${namespace} apply -f -