Overview

Volcengine Provider is a webhook-based provider built for ExternalDNS. It bridges ExternalDNS and Volcengine DNS so that every DNS record (create, update, delete) emitted by ExternalDNS is translated into the corresponding Volcengine DNS API call through a lightweight webhook server.

Security and privacy

This project takes security seriously. For vulnerability reporting and supported versions, see SECURITY.md

Features

• Webhook integration – dynamic DNS-record management via ExternalDNS webhooks
• Volcengine DNS native – all operations are forwarded to Volcengine DNS service
• Flexible configuration – configurable through files or environment variables

Installation

Prerequisites

• Helm 3.x installed
• [Optional] Volcengine API key (AK/SK) and VPC information ready
• [Optional] VKE IRSA ready

[Optional] Prepare Volcengine API AK SK

Volcengine API key (AK/SK) should be created with the following permissions:

{
  "Statement": [
    {
      "Effect": "Allow",
      "Action": [
        "private_zone:*"
      ],
      "Resource": [
        "*"
      ]
    }
  ]
}

[Optional] Prepare VKE IRSA

https://www.volcengine.com/docs/6460/1324604

[Optional] Prepare cross-account AssumeRole

If you need to use credentials from account 100000 to assume a role in account 100001, prepare a target role in account 100001 with permissions required by PrivateZone, then grant sts:AssumeRole to the source identity from account 100000 in the target role trust policy.

Note: when a role in account 100000 assumes a role in account 100001, the trust policy in account 100001 should explicitly include the role from account 100000, not only the account root. Example:

{
  "Statement": [
    {
      "Effect": "Allow",
      "Action": [
        "sts:AssumeRole"
      ],
      "Principal": {
        "IAM": [
          "trn:iam::100000:root",
          "trn:iam::100000:role/dns-demo-role"
        ]
      }
    }
  ]
}

Deploy with Helm

1. Export environment variables

   export VOLCENGINE_CREDENTILALS_PROVIDER="aksk"         # support aksk or irsa
   export VOLCENGINE_SECRET_NAME="your-secret-with-ak-sk" # optional if use aksk
   export VOLCENGINE_OIDC_ROLE_TRN="your-oidc-role-trn"   # optional if use irsa
   export VOLCENGINE_ROLE_TRN="your-target-role-trn"      # optional if need AssumeRole, including cross-account access
   export VOLCENGINE_ROLE_SESSION_NAME="external-dns"     # optional
   export VOLCENGINE_DURATION_SECONDS="3600"              # optional
   export VOLCENGINE_AK="your-ak"
   export VOLCENGINE_SK="your-sk"
   export VOLCENGINE_VPC="your-vpc-id"
   export VOLCENGINE_REGION="cn-beijing"
   export VOLCENGINE_PRIVATEZONE_ENDPOINT="open.volcengineapi.com"
   export VOLCENGINE_STS_ENDPOINT="open.volcengineapi.com"
   export TARGET_DOMAINS="{test.com,test2.com}"

2. [Optional] Create the Secret

   kubectl create secret generic ${VOLCENGINE_SECRET_NAME} \
   --from-literal=access-key=${VOLCENGINE_AK} \
   --from-literal=secret-key=${VOLCENGINE_SK} \
   --namespace kube-system

3. Install the chart

   helm upgrade --install external-dns \
   manifests/externaldns \
   --namespace kube-system \
   --set userConfig.env.provider.credentialsProvider=${VOLCENGINE_CREDENTILALS_PROVIDER} \
   --set userConfig.env.provider.secretName=${VOLCENGINE_SECRET_NAME} \
   --set userConfig.env.provider.oidcRoleTrn=${VOLCENGINE_OIDC_ROLE_TRN} \
   --set userConfig.env.provider.roleTrn=${VOLCENGINE_ROLE_TRN} \
   --set userConfig.env.provider.roleSessionName=${VOLCENGINE_ROLE_SESSION_NAME} \
   --set userConfig.env.provider.durationSeconds=${VOLCENGINE_DURATION_SECONDS} \
   --set userConfig.env.provider.vpc=${VOLCENGINE_VPC} \
   --set userConfig.env.provider.region=${VOLCENGINE_REGION} \
   --set userConfig.env.provider.privatezoneEndpoint=${VOLCENGINE_PRIVATEZONE_ENDPOINT} \
   --set userConfig.env.provider.stsEndpoint=${VOLCENGINE_STS_ENDPOINT} \
   --set userConfig.args.controller.domainFilters=${TARGET_DOMAINS} \
   --set publicConfig.image.controller.repository=registry.k8s.io/external-dns/external-dns \
   --set publicConfig.image.provider.repository=volcengine/external-dns-volcengine-webhook

4. Verify

   helm list -n kube-system
   kubectl get pods -n kube-system -l app.kubernetes.io/name=external-dns

Helm parameters

Parameter	Description	Default	Required
userConfig.env.provider.credentialsProvider	Provider used to obtain Volcengine API credentials. Valid values: aksk (default) or irsa	aksk	yes
userConfig.env.provider.secretName	Kubernetes secret that contains Volcengine Access Key (access-key) and Secret Key (secret-key), must set if credentialsProvider=aksk	–	no
userConfig.env.provider.oidcRoleTrn	Volcengine OpenID Connect (OIDC) role to assume for API access, must set if credentialsProvider=irsa	–	no
userConfig.env.provider.roleTrn	Target role TRN used by STS AssumeRole after source credentials are resolved. For cross-account access, configure this as the target account role.	–	no
userConfig.env.provider.roleSessionName	Session name used when calling STS AssumeRole.	external-dns	no
userConfig.env.provider.durationSeconds	Session duration in seconds for STS AssumeRole.	provider default	no
userConfig.env.provider.vpc	Volcengine VPC identifier where the DNS zone is located.	–	yes
userConfig.env.provider.region	Volcengine region in which the DNS zone resides.	cn-beijing	yes
userConfig.env.provider.privatezoneEndpoint	Custom Volcengine OpenAPI privatezone endpoint (overrides built-in global endpoint).	open.volcengineapi.com	yes
userConfig.env.provider.stsEndpoint	Custom Volcengine OpenAPI sts endpoint (overrides built-in global endpoint).	sts.volcengineapi.com	yes
userConfig.args.controller.domainFilters	Limit possible target zones by a list of domain suffixes; specify multiple times or use comma-separated values (same as –domain-filter).	–	yes
userConfig.args.controller.policy	How DNS records are synchronized between source and provider. Valid values: sync (create/update/delete) and upsert-only (create/update, never delete) (same as –policy).	upsert-only	no
userConfig.args.controller.registry	Registry implementation used to keep track of DNS record ownership. Valid values: txt (default TXT registry) or noop (no ownership records) (same as –registry).	txt	no
userConfig.args.controller.txtOwnerId	Identifier used as the owner for TXT registry records; must be unique across concurrent ExternalDNS instances (same as –txt-owner-id).	–	no
userConfig.args.controller.txtPrefix	Prefix added to ownership TXT record names to avoid collisions with real DNS records (same as –txt-prefix).	externaldns-%{record_type}.	no
userConfig.args.controller.txtWildcardReplacement	Wildcard string replacement to use in TXT record names for wildcard * (same as –txt-wildcard-replacement).	wildcard	no
userConfig.args.provider.logLevel	Enable verbose debug logging in the Volcengine webhook provider.	info	no
publicConfig.image.controller.repository	Container image for the ExternalDNS controller.	registry.k8s.io/external-dns/external-dns	no
publicConfig.image.provider.repository	Container image for the Volcengine webhook provider.	volcengine/external-dns-volcengine-webhook	no

Tip: override defaults with –set or supply a custom values.yaml via -f.

When using cross-account authorization:

• If credentialsProvider=aksk, secretName provides the source account credentials and roleTrn is the target account role.
• If credentialsProvider=irsa, oidcRoleTrn is the source account role obtained through IRSA and roleTrn is the target account role.
• In the target account role trust policy, explicitly include the source account role ARN/TRN when the source identity is a role.

Examples

external-dns support to reconcile LoadBalancer type service and ingress to dns record by default.

external-dns default reconcile policy is upsert-only.

Service(LoadBalancer Type)

kubectl apply -f example/service.yaml

apiVersion: v1
kind: Service
metadata:
  name: nginx-service
  annotations:
    external-dns.alpha.kubernetes.io/hostname: nginx.test.com.  # expect to create record with hostname nginx.test.com
    external-dns.alpha.kubernetes.io/ttl: "300"                 # expect to set ttl to 300
spec:
  selector:
    app: nginx     
  ports:
    - protocol: TCP
      port: 80    
      targetPort: 80   
  type: LoadBalancer   # LoadBalancer

Ingress

kubectl apply -f example/ingress.yaml

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  annotations:
    vke.volcengine.com/ingress-type: ingress-nginx
    external-dns.alpha.kubernetes.io/ttl: "300" # expect to set ttl to 300
  name: nginx-ingress-external
spec:
  ingressClassName: nginx
  rules:
    - host: nginx-ingress-external.test.com   # expect to create record with hostname nginx-ingress-external.test.com
      http:
        paths:
          - backend:
              service:
                name: nginx-service
                port:
                  number: 80
            path: /path1
            pathType: Prefix
    - host: nginx-ingress-external2.test.com  # expect to create record with hostname nginx-ingress-external2.test.com
      http:
        paths:
          - backend:
              service:
                name: nginx-service
                port:
                  number: 80
            path: /path2
            pathType: Prefix