Renew TLS certificates on Astronomer Software

Once you set up a TLS certificate for Astronomer, you'll need to establish a process for periodically renewing the certificate. This can be done in one of two ways:

• Automatic renewal: Let's Encrypt provides a service that automatically renews your TLS certificate every 90 days. We recommend this option for smaller organizations where the DNS administrator and cluster administrator are either the same person or on the same team.
• Manual renewal: Manual renewal works similarly to the initial certificate creation process, except that you replace your existing certificate by creating a new certificate. We recommend this method for large organizations that have their own processes for issuing certificates.

Automatically renew TLS certificates Using Let's Encrypt

Let's Encrypt is a certificate authority that provides free, 90-day certificates using the ACME protocol. You can use the Cert Manager project for Kubernetes to automatically renew certificates.

1. Install the Kubernetes Cert Manager by following the official installation guide.

2. If you're running Astronomer on AWS, grant your nodes access to Route 53 by adding the following CloudFormation snippet to your nodes' Instance Profile (if you don't use AWS, complete whatever setup is necessary to authenticate Cert Manager to your DNS):

   Type: "AWS::IAM::Role"
   Properties:
     RoleName: instance-profile-role
     Policies:
       - PolicyName: instance-profile-policy
         PolicyDocument:
           Version: '2012-10-17'
           Statement:
             - Effect: Allow
               Action: route53:GetChange
               Resource: arn:aws:route53:::change/*
             - Effect: Allow
               Action:
                 - route53:ChangeResourceRecordSets
                 - route53:ListResourceRecordSets
               # Use the second Resource format if you're updating this through the AWS UI
               Resource: !Sub arn:aws:route53:::hostedzone/${HostedZoneIdLookup.HostedZoneId}
             - Effect: Allow
               Action: route53:ListHostedZonesByName
               Resource: '*'
     AssumeRolePolicyDocument:
       Version: "2012-10-17"
       Statement:
         - Effect: "Allow"
           Principal:
             Service:
               - "ec2.amazonaws.com"
           Action:
             - "sts:AssumeRole"

   For more information on how to complete this setup, refer to AWS documentation.

3. Create a "ClusterIssuer" resource that declares how requests for certificates will be fulfilled. To do so, first create a clusterissuer.yaml file with the following values:

   apiVersion: cert-manager.io/v1
   kind: ClusterIssuer
   metadata:
       name: letsencrypt-prod
   spec:
       acme:
           email: <your-email>
           server: https://acme-v02.api.letsencrypt.org/directory
           privateKeySecretRef:
               name: cert-manager-issuer-secret-key
           solvers:
           - selector: {}
             dns01:
                route53:
                   region: <your-server-region>

   Then, create the ClusterIssuer by running the following command:

   kubectl apply -f clusterissuer.yaml -n astronomer

4. Create a "Certificate" resource that declares the type of certificate you'll request from Let's Encrypt. To do so, first create a certificate.yaml file, replacing BASE_DOMAIN with yours:

   apiVersion: cert-manager.io/v1
   kind: Certificate
   metadata:
       name: acme-crt
   spec:
       secretName: astronomer-tls
       dnsNames:
           - BASE_DOMAIN
           - app.BASE_DOMAIN
           - deployments.BASE_DOMAIN
           - registry.BASE_DOMAIN
           - houston.BASE_DOMAIN
           - grafana.BASE_DOMAIN
           - kibana.BASE_DOMAIN
           - install.BASE_DOMAIN
           - prometheus.BASE_DOMAIN
           - alertmanager.BASE_DOMAIN
       issuerRef:
           name: letsencrypt-prod
           kind: ClusterIssuer
           group: cert-manager.io

   Then, create the certificate by running the following command and waiting a few minutes:

   kubectl apply -f certificate.yaml -n astronomer

5. Ensure that the certificate was created by running:

   kubectl get certificates -n astronomer

6. Note your certificate name for when you create a Kubernetes TLS secret and push it to your Software configuration as described in the Software installation guide (AWS, GCP, AKS).

Manually renew TLS certificates

Larger organizations with dedicated security teams will likely have their own processes for requesting and renewing TLS certificates. Regardless, there are specific steps you have to complete for Astronomer when renewing TLS certificates:

1. Delete your current TLS certificate by running the following command:

   kubectl delete secret astronomer-tls -n astronomer

2. Follow the instructions for requesting a TLS certificate from your organization's security team as described in Step 4: Configure TLS. The linked guide is written for users installing Astronomer on AWS, but this step is the same regardless of which service you use.

3. Restart your Houston, nginx, and registry pods to begin using the new certificate by running the following commands:

   kubectl rollout restart deployments -n astronomer
   kubectl rollout restart statefulsets -n astronomer