All API communication between Antrea control plane components is encrypted with TLS. The TLS certificates that Antrea requires can be automatically generated. You can also provide your own certificates. This page explains the certificates that Antrea requires and how to configure and rotate them for Antrea.
Currently Antrea only requires a single server certificate for the antrea-controller API server endpoint, which is for the following communication: - The antrea-agents talks to the antrea-controller for fetching the computed NetworkPolicies - The kube-aggregator (i.e. kube-apiserver) talks to the antrea-controller for proxying antctl's requests (when run in "controller" mode)
Antrea doesn't require client certificates for its own components as it delegates authentication and authorization to the Kubernetes API, using Kubernetes ServiceAccount tokens for client authentication.
By default, antrea-controller generates a self-signed certificate. You can
override the behavior by providing your own certificates.
Either way, the antrea-controller will distribute the CA certificate as a
antrea-ca in the Antrea deployment Namespace and inject it
into the APIServices resources created by Antrea in order to allow its clients
(i.e. antrea-agent, kube-apiserver) to perform authentication.
Typically, clients that wish to access the antrea-controller API can
authenticate the server by validating against the CA certificate published in
Since Antrea v0.8.2, you can provide your own certificates to Antrea. To do so,
you must set the
selfSignedCert field of
so that the antrea-controller will read the certificate key pair from the
antrea-controller-tls Secret. The example manifests and descriptions below
assume Antrea is deployed in the
kube-system Namespace. If you deploy Antrea
in a different Namepace, please update the Namespace name in the manifests
apiVersion: v1 kind: ConfigMap metadata: labels: app: antrea name: antrea-config namespace: kube-system data: antrea-controller.conf: | selfSignedCert: false
You can generate the required certificate manually, or through cert-manager. Either way, the certificate must be issued with the following key usages and DNS names:
X509 key usages: - digital signature - key encipherment - server auth
DNS names: - antrea.kube-system.svc - antrea.kube-system.svc.cluster.local
Note: It assumes you are using
cluster.local as the cluster domain, you
should replace it with the actual one of your Kubernetes cluster.
You can then create the
antrea-controller-tls Secret with the certificate key
pair and the CA certificate in the following form:
apiVersion: v1 kind: Secret # The type can also be Opaque. type: kubernetes.io/tls metadata: name: antrea-controller-tls namespace: kube-system data: ca.crt: <BASE64 ENCODED CA CERTIFICATE> tls.crt: <BASE64 ENCODED TLS CERTIFICATE> tls.key: <BASE64 ENCODED TLS KEY>
You can use
kubectl apply -f <PATH TO SECRET YAML> to create the above secret,
kubectl create secret:
kubectl create secret generic antrea-controller-tls -n kube-system \ --from-file=ca.crt=<PATH TO CA CERTIFICATE> --from-file=tls.crt=<PATH TO TLS CERTIFICATE> --from-file=tls.key=<PATH TO TLS KEY>
If you set up cert-manager to manage your certificates, it can be used to issue and renew the certificate required by Antrea.
To get started, follow the cert-manager installation documentation to deploy cert-manager
Certificate should be created in the
kube-system namespace. For example,
Certificate may look like:
apiVersion: cert-manager.io/v1alpha2 kind: Certificate metadata: name: antrea-controller-tls namespace: kube-system spec: secretName: antrea-controller-tls commonName: antrea dnsNames: - antrea.kube-system.svc - antrea.kube-system.svc.cluster.local usages: - digital signature - key encipherment - server auth issuerRef: # Replace the name with the real Issuer you configured. name: ca-issuer # We can reference ClusterIssuers by changing the kind here. # The default value is Issuer (i.e. a locally namespaced Issuer) kind: Issuer
Certificate is created, you should see the
Secret created in the
Note it may take up to 1 minute for Kubernetes to propagate the Secret update to the antrea-controller Pod if the Pod starts before the Secret is created.
Antrea v0.8.2 and higher supports certificate rotation. It can be achieved by
simply updating the
antrea-controller-tls Secret. The
antrea-controller will react to the change, updating its serving certificate and
re-distributing the latest CA certificate (if applicable).
If you are using cert-manager to issue the certificate, it will renew the certificate before expiry and update the Secret automatically.
If you are using certificates signed by Antrea, Antrea will rotate the certificate automatically before expiration.