TLS Certificates

Applications that publish HTTP endpoints can be protected by TLS certificates. If you've enabled Acorn's Let's Encrypt integration, a valid certificate will be provisioned for your app's endpoints. This only applies to oss-acorn.io generated endpoints. For custom endpoints configured using the publish flag, Acorn relies on external cert-manager to issue certificates. For more information on how to configure cert-manager, see Issuing custom domain certs.

Manually adding certificates

If you don't wish to use Acorn's Let's Encrypt integration, you can configure certificates manually or by integrating with cert-manager. Acorn will automatically look for SANs in secrets of type kubernetes.io/tls for the exposed FQDN of the application in the Acorn namespace.

The following examples assume you are deploying an app and plan to host on my-app.example.com

Add existing certificates using kubectl

Before launching the application pre-create a secret in the acorn namespace containing the certificate like so:

kubectl create secret tls my-app-tls-secret --cert=path/to/my-app-tls.cert --key=path/to/my-app-tls.key

Add with Cert-Manager

If you are already using Cert-Manager today, you can leverage it with Acorn right away. First you must create a certificate resource in the Acorn namespace:

kubectl apply -n acorn -f ./my-cert.yaml

# my-cert.yaml
apiVersion: cert-manager.io/v1
kind: Certificate
metadata:
  name: registry-studio-cert
spec:
  dnsNames:
  - my-app.example.com
  issuerRef:
    group: cert-manager.io
    kind: ClusterIssuer
    name: prod-issuer
  secretName: my-app-tls-secret

Cert-Manager will create a certificate for my-app.example.com and store it in a secret my-app-tls-secret.

Consume the secret

Once you have manually created the TLS secret using one of the methods above you can consume it in your application.

When you deploy the application Acorn, you can launch with the FQDN of your app.

acorn run -p my-app.example.com:web [MY_APP_IMAGE]

Acorn will automatically inspect each certificate in the Acorn namespace for one that can be used with my-app.example.com. If no TLS secret is found with that FQDN, it will be exposed on HTTP only.

Issuing custom domain certs

Acorn's Let's Encrypt integration does not issue certificates for custom domains. Instead, you will rely on external cert-manager to issue certificates. To do so, you will need to create a cluster-issuer first. For more information on how to install and configure cert-manager, see cert-manager docs.

apiVersion: cert-manager.io/v1
kind: ClusterIssuer
metadata:
  name: letsencrypt-prod
spec:
  acme:
    server: https://acme-v02.api.letsencrypt.org/directory
    email: [email protected]
    privateKeySecretRef:
      name: letsencrypt-prod
    solvers:
      - http01:
          ingress:
            ingressClassName: traefik

Modify the ingressClassName to match the ingress controller you are using. For example, if you are using the NGINX ingress controller, you will need to change it to nginx. Once you have created the cluster-issuer, pass the cluster-issuer's name to acorn install so that Acorn knows which cluster-issuer to apply to the ingress resource.

Once you have created the cluster issuer, pass the cluster issuer's name to acorn install so that acorn knows where to apply the cluster issuer to the ingress resource.

acorn install --cert-manager-issuer=letsencrypt-prod