Perform JSON escaping of strings (#3919)

parts/k8s/kubernetesconfigs.sh

@@ -134,6 +134,9 @@ function configureK8s() {
     set +x
     echo "${KUBELET_PRIVATE_KEY}" | base64 --decode > "${KUBELET_PRIVATE_KEY_PATH}"
     echo "${APISERVER_PUBLIC_KEY}" | base64 --decode > "${APISERVER_PUBLIC_KEY_PATH}"
+    # Perform the required JSON escaping for special characters " and \
+    SERVICE_PRINCIPAL_CLIENT_SECRET=$(echo $SERVICE_PRINCIPAL_CLIENT_SECRET | sed "s|\\\\|\\\\\\\|g")
+    SERVICE_PRINCIPAL_CLIENT_SECRET=$(echo $SERVICE_PRINCIPAL_CLIENT_SECRET | sed 's|"|\\"|g')
     cat << EOF > "${AZURE_JSON_PATH}"
 {
     "cloud":"${TARGET_ENVIRONMENT}",