About this approach

AWS Private CA is a managed CA that you can use to your secure apps and devices with private TLS certificates. In this setup, you use the AWS Private CA to generate and store your root CA and subordinate CAs that you use to generate client and server TLS certificates for your relay architecture. To manage the lifecycle of the server and agent certificates, you also install cert-manager. Cert-manager is a Kubernetes controller that helps you automate the process of obtaining and renewing certificates from various PKI providers, such as AWS Private CA or Vault.

With this approach, you get the following benefits:

  • Secure storage of root certificates and keys.
  • AWS subordinate CA serves as an additional security layer for your root CA.
  • Automatically obtain and renew server and client TLS certificates with cert-manager.
  • Possibility to reuse this architecture for other certificates, such as the Istio root and intermediate CA certificates.

Before you begin

Save the kubeconfig contexts for your clusters. Run kubectl config get-contexts, look for your cluster in the CLUSTER column, and get the context name in the NAME column. Note: Do not use context names with underscores. The generated certificate that connects workload clusters to the management cluster uses the context name as a SAN specification, and underscores in SAN are not FQDN compliant. You can rename a context by running kubectl config rename-context "<oldcontext>" <newcontext>.
  export MGMT_CLUSTER=<mgmt-cluster-name>
export REMOTE_CLUSTER=<remote-cluster-name>
export MGMT_CONTEXT=<management-cluster-context>
export REMOTE_CONTEXT=<remote-cluster-context>
  

Step 1: Install cert-manager

  1. In your management cluster, install cert-manager. For more information about installation options and versions, see the cert-manager documentaton.

    • kubectl installation:
        kubectl apply --context $MGMT_CONTEXT -f https://github.com/jetstack/cert-manager/releases/download/v1.5.4/cert-manager.yaml
        
    • Helm installation:
        helm repo add jetstack https://charts.jetstack.io
      helm repo update
      helm install \
        cert-manager jetstack/cert-manager \
        --namespace cert-manager \
        --create-namespace \
        --version v1.5.4 \
        --set installCRDs=true
        
  2. Verify that cert-manager was successfully installed.

      kubectl get pod -n cert-manager --context $MGMT_CONTEXT
      

    Example output:

      NAME                                       READY   STATUS    RESTARTS   AGE
    cert-manager-7c6f78c46d-247br              1/1     Running   0          17s
    cert-manager-cainjector-668d9c86df-7cqb8   1/1     Running   0          17s
    cert-manager-webhook-764b556954-2m4zf      1/1     Running   0          17s
      

Step 2: Install the AWS Private CA issuer plug-in

  1. Install the AWS Private CA issuer plug-in for cert-manager. For more information, see the aws-privateca-issuer plug-in documentation

      helm repo add awspca https://cert-manager.github.io/aws-privateca-issuer
    helm repo update
    helm upgrade pca-issuer \
      --install awspca/aws-privateca-issuer \
      --namespace cert-manager \
      --set image.tag=v1.2.1
      
  2. Verify that the plug-in was successfully installed.

      kubectl get pod -n cert-manager --context $MGMT_CONTEXT
      

    Example output:

      NAME                                               READY   STATUS    RESTARTS   AGE
    ...
    pca-issuer-aws-privateca-issuer-6768d7454b-w8d4l   1/1     Running   0          15s
      

Step 3: Generate the relay root CA

Create and securely store the relay root CA in AWS Certificate Manager Private Certificate Authority (AWS ACM PCA).

  1. If it doesn’t already exist, create the gloo-mesh namespace.

      kubectl create namespace gloo-mesh --context $MGMT_CONTEXT
      
  2. Create the root CA in ACM PCA.

      # Generate CA config file
    echo '''
    {
       "KeyAlgorithm":"RSA_2048",
       "SigningAlgorithm":"SHA256WITHRSA",
       "Subject":{
          "CommonName":"relay-root-ca"
       }
    }
    ''' > ca_config.json
    # Create CA in ACM PCA
    REGION=us-east-1
    CA_ARN=$(aws acm-pca create-certificate-authority \
         --certificate-authority-configuration file://ca_config.json \
         --certificate-authority-type "ROOT" \
         --idempotency-token 01234567 \
         --region $REGION \
         --tags  Key=Name,Value=relay-root-ca| jq -r '.CertificateAuthorityArn')
    # Example response payload 
    # {
    #   "CertificateAuthorityArn": "arn:aws:acm-pca:us-east-1:123456789:certificate-authority/123456789-debf-4513-89f7-c1834d5ffbd5"
    # }
    
    # download Root CA CSR from AWS
    aws acm-pca get-certificate-authority-csr \
        --region $REGION \
        --certificate-authority-arn $CA_ARN \
        --output text > relay-root-ca.csr
    
    # Issue Root Certificate
    ISSUE_CERTIFICATE_RESPONSE=$(aws acm-pca issue-certificate \
        --certificate-authority-arn $CA_ARN \
        --csr fileb://relay-root-ca.csr \
        --region $REGION \
        --signing-algorithm "SHA256WITHRSA" \
        --template-arn arn:aws:acm-pca:::template/RootCACertificate/V1 \
        --validity Value=3650,Type="DAYS" \
        --idempotency-token 1234567 \
        --output json | jq -r '.CertificateArn')
    
    CERTARN=$ISSUE_CERTIFICATE_RESPONSE
    
    # Download Certificate
    aws acm-pca get-certificate \
        --certificate-authority-arn $CA_ARN \
        --certificate-arn $CERTARN \
        --region $REGION \
        --output text > relay-root-ca.pem
    
    # Upload certificate to AWS
    aws acm-pca import-certificate-authority-certificate \
        --certificate-authority-arn $CA_ARN \
        --region $REGION \
        --certificate fileb://relay-root-ca.pem
      
  3. Create an AWS user for the relay root CA.

      aws iam create-user gloo-mesh-acm --region $REGION
      
  4. Create an IAM policy for the relay root CA.

      $POLICY_ARN=$(aws iam create-policy \
        --policy-name GlooMeshRelayCA \
        --policy-document \
    '{
      "Version": "2012-10-17",
      "Statement": [
        {
          "Sid": "awspcaissuer",
          "Action": [
            "acm-pca:DescribeCertificateAuthority",
            "acm-pca:GetCertificate",
            "acm-pca:IssueCertificate"
          ],
          "Effect": "Allow",
          "Resource": "$CA_ARN"
        }
      ]
    }' | jq -r '.Policy.Arn')
      
    • Note: For cross account ACM management, see Resource-based policies in the AWS docs.
    • For an example template, download this PCACrossAccountPolicy.json file and apply it via the CLI.
        aws acm-pca put-policy --region ${region} --resource-arn arn:aws:acm-pca:us-east-1:${control_plane_account}:certificate-authority/${cert_authority_id} --policy file://PCACrossAccountPolicy.json
        
  5. Add the policy to the gloo-mesh-acm user.

      aws iam attach-user-policy --policy-arn $POLICY_ARN --user-name gloo-mesh-acm
      
  6. Generate an access keypair for the user, and add the keypair to your cluster.

      aws iam create-access-key --user-name gloo-mesh-acm
    # Example Reponse
    # {
    #     "AccessKey": {
    #         "UserName": "Bob",
    #         "Status": "Active",
    #         "CreateDate": "2015-03-09T18:39:23.411Z",
    #         "SecretAccessKey": "wJalrXUtnFEMI/K7MDENG/bPxRfiCYzEXAMPLEKEY",
    #         "AccessKeyId": "AKIAIOSFODNN7EXAMPLE"
    #     }
    # }
    
    #upload secrets to kubernetes
    
    AWS_ACCESS_KEY_ID=<key_id>
    SECRET_ACCESS_KEY=<secret>
    
    kubectl create secret generic gloo-mesh-acm-credentials \
      --namespace gloo-mesh \
      --from-literal=AWS_ACCESS_KEY_ID=$AWS_ACCESS_KEY_ID \
      --from-literal=AWS_SECRET_ACCESS_KEY=$SECRET_ACCESS_KEY \
      --context $MGMT_CONTEXT
      
  7. Create a cert-manager issuer for the CA.

      cat << EOF | kubectl apply --context $MGMT_CONTEXT -f -
    apiVersion: awspca.cert-manager.io/v1beta1
    kind: AWSPCAIssuer
    metadata:
      name: relay-root-ca
      namespace: gloo-mesh
    spec:
      arn: $CA_ARN
      region: $REGION
      secretRef:
        namespace: gloo-mesh
        name: gloo-mesh-acm-credentials
    EOF
      

Step 4: Create the server TLS certificate

To generate the gloo-mesh-mgmt-server server certificates, create a cert-manager certificate and refer to the ACM PCA issuer.

  cat << EOF | kubectl apply --context $MGMT_CONTEXT -f -
kind: Certificate
apiVersion: cert-manager.io/v1
metadata:
  name: gloo-mesh-mgmt-server
  namespace: gloo-mesh
spec:
  commonName: gloo-mesh-mgmt-server
  dnsNames:
    - "*.gloo-mesh"
  # 1 year life
  duration: 8760h0m0s
  issuerRef:
    group: awspca.cert-manager.io
    kind: AWSPCAIssuer
    name: relay-root-ca
  renewBefore: 8736h0m0s
  secretName: relay-server-tls-secret
  usages:
    - server auth
    - client auth
  privateKey:
    algorithm: "RSA"
    size: 4096
EOF
  

Step 5: Create the client TLS certificate

Generate a gloo-mesh-agent client certificate for each workload cluster. Be sure to repeat these steps for each workload cluster that you plan to register with Gloo Mesh Core.

  1. Create a cert-manager certificate and refer to the ACM PCA issuer.

      CLUSTER_NAME=$REMOTE_CLUSTER
    CLUSTER_CONTEXT=$REMOTE_CONTEXT
    
    cat << EOF | kubectl apply --context $MGMT_CONTEXT -f -
    kind: Certificate
    apiVersion: cert-manager.io/v1
    metadata:
      name: gloo-mesh-agent-$CLUSTER_NAME
      namespace: gloo-mesh
    spec:
      commonName: gloo-mesh-agent-$CLUSTER_NAME
      dnsNames:
        # Must match the cluster name used in the helm chart install
        - "$CLUSTER_NAME"
      # 1 year life
      duration: 8760h0m0s
      issuerRef:
        group: awspca.cert-manager.io
        kind: AWSPCAIssuer
        name: relay-root-ca
      renewBefore: 8736h0m0s
      secretName: gloo-mesh-agent-$CLUSTER_NAME-tls-cert
      usages:
        - server auth
        - client auth
      privateKey:
        algorithm: "RSA"
        size: 4096
    EOF
      
  2. Copy the TLS secret to the workload cluster.

      kubectl get secret gloo-mesh-agent-$CLUSTER_NAME-tls-cert \
      --namespace gloo-mesh \
      --output json \
      --context $MGMT_CONTEXT \
      | jq 'del(.metadata.creationTimestamp,.metadata.resourceVersion,.metadata.uid)' \
      | kubectl apply --context $CLUSTER_CONTEXT -f -
      

Verify the cert-manager resources

For clusters that have cert-manager installed, verify that your cert-manager issuer and certificate resources are ready. If the READY column says False for any of the following resources, describe the resource for more details and resolve the issue before continuing.

  kubectl get issuer -n gloo-mesh --context $MGMT_CONTEXT
kubectl get certificates -n gloo-mesh --context $MGMT_CONTEXT
  

Now that your custom certificates are created, continue to the next section to modify your Gloo Mesh deployment to use these certificates.

Step 6: Install the Gloo management server and agents

Set up Gloo Mesh Core to use the client and server TLS certificates that you created earlier.

  1. Prepare the Helm installation settings for the Gloo management server.

     
    glooMgmtServer:
     relay:
         disableCa: true
         disableCaCertGeneration: true
         disableTokenGeneration: true
         # Secret containing server TLS certs used to secure the management server.
         tlsSecret:
             name: relay-server-tls-secret

  2. Install a new or upgrade an existing Gloo management server with the Helm settings from the previous step.

  3. Prepare the Helm installation settings for the Gloo agent.

      
    glooAgent:
      relay:
        # gloo-mesh-mgmt-server IP address
        serverAddress: $MGMT_SERVER_NETWORKING_ADDRESS
        # Custom certs: Secret containing client TLS certs used to identify the Gloo agent to the management server. If you do not specify a clientTlssSecret, you must specify a tokenSecret and a rootTlsSecret.
        clientTlsSecret:
          name: relay-client-tls-secret
        tokenSecret:
          # Key value of the data within the Kubernetes secret.
          key: token
          # Name of the Kubernetes secret.
          name: relay-identity-token-secret
          # Namespace of the Kubernetes secret.
          namespace: ""
      
  4. Register the workload cluster or upgrade an existing Gloo agent with the Helm settings from the previous step.

Verifying your relay certificate setup

  1. Check that the relay connection between the management server and workload agents is healthy.
    1. Forward port 9091 of the gloo-mesh-mgmt-server pod to your localhost.
        kubectl port-forward -n gloo-mesh --context $MGMT_CONTEXT deploy/gloo-mesh-mgmt-server 9091
        
    2. In your browser, connect to http://localhost:9091/metrics.
    3. In the metrics UI, look for the following lines. If the values are 1, the agents in the workload clusters are successfully registered with the management server. If the values are 0, the agents are not successfully connected.
        relay_pull_clients_connected{cluster="cluster1"} 1
      relay_pull_clients_connected{cluster="cluster2"} 1
      # HELP relay_push_clients_connected Current number of connected Relay push clients (Relay Agents).
      # TYPE relay_push_clients_connected gauge
      relay_push_clients_connected{cluster="cluster1"} 1
      relay_push_clients_connected{cluster="cluster2"} 1
        
  2. Review the Gloo UI. Check that the Overall Mesh Status is healthy and that your remote clusters are registered without any configuration issues.
      meshctl dashboard --kubecontext $MGMT_CONTEXT
      
  3. If the setup is unsuccessful, continue to Troubleshooting.

Troubleshooting relay certificates

  1. Review the health of your Gloo pods in the management and remote clusters.

    1. Check that the gloo-mesh-mgmt-server and gloo-mesh-agent pods are running.

        kubectl get pods -n gloo-mesh --context ${MGMT_CONTEXT}
      kubectl get pods -n gloo-mesh --context ${REMOTE_CONTEXT}
        
    2. If the pods are not running, describe the pods and check the State and Last State sections for error messages and reasons why the pod might not be healthy. For example, the following error messages in the gloo-mesh-mgmt-server and gloo-mesh-agent pods indicate that the secret is misnamed or missing. Check the secrets and names, upgrade your Helm installation, and try again.

      • Example error message for gloo-mesh-mgmt-server pod:
        Message:   3 errors occurred:
          * no tls secret found for grpc server: Secret "relay-server-tls-secret" not found
          * could not find forwarding server token: no token secret found: Timeout: failed waiting for *v1.Secret Informer to sync
          * no tls secret found for grpc server: Secret "relay-server-tls-secret" not found
        
      • Example error message for gloo-mesh-agent pod:
        Events:
        Type     Reason       Age                    From     Message
        ----     ------       ----                   ----     -------
        Normal   Created      84m (x25 over 3h28m)   kubelet  Created container gloo-mesh-agent
        Normal   Pulled       84m (x24 over 3h28m)   kubelet  Container image "gcr.io/gloo-mesh/gloo-mesh-agent:1.2.3" already present on machine
        Normal   Started      84m (x25 over 3h28m)   kubelet  Started container gloo-mesh-agent
        Warning  FailedMount  84m                    kubelet  MountVolume.SetUp failed for volume "kube-api-access-zlr9b" : [failed to fetch token: Post "https://kind2-control-plane:6443/api/v1/namespaces/gloo-mesh/serviceaccounts/gloo-mesh-agent/token": read tcp 172.18.0.5:47314->172.18.0.5:6443: use of closed network connection, failed to sync configmap cache: timed out waiting for the condition]
        Warning  FailedMount  84m                    kubelet  MountVolume.SetUp failed for volume "kube-api-access-zlr9b" : [failed to fetch token: Post "https://kind2-control-plane:6443/api/v1/namespaces/gloo-mesh/serviceaccounts/gloo-mesh-agent/token": read tcp 172.18.0.5:57262->172.18.0.5:6443: use of closed network connection, failed to sync configmap cache: timed out waiting for the condition]
        Warning  FailedMount  83m                    kubelet  MountVolume.SetUp failed for volume "kube-api-access-zlr9b" : [failed to fetch token: Post "https://kind2-control-plane:6443/api/v1/namespaces/gloo-mesh/serviceaccounts/gloo-mesh-agent/token": http2: client connection force closed via ClientConn.Close, failed to sync configmap cache: timed out waiting for the condition]
        Warning  BackOff      72s (x522 over 3h28m)  kubelet  Back-off restarting failed container
        
  2. Check the Kubernetes logs for the gloo-mesh-mgmt-server and gloo-mesh-agent pods in each cluster for errors. Look for errors during the grpc connection.

    • For example, the following error message indicates that the gloo-mesh-mgmt-server load balancer IP address was set incorrectly for the agent during the Helm installation.
      {"level":"warn","ts":"2021-11-02T19:56:42.197Z"caller":"zap/
    grpclogger.go:85","msg":"[core]grpcaddrConn.createTransport
    failed to connect to {34.145.18106:9900:9900 
    gloo-mesh-mgmt-server.gloo-mesh <nil> <nil>}. Err: connection 
    error: desc = \"transport: Error while dialing dial tcp: address 
    34.145.184.106:9900:9900 too many colons in address\".
      
    • The following gloo-mesh-agent pod error indicates that you need to follow the steps in ca.crt.
      {"level":"fatal","ts":1640102555.6522746,"msg":"secrets \"relay-root-tls-secret\" not found","version":"1.3.0-beta6","stacktrace":"runtime.main\n\t/usr/local/go/src/runtime/proc.go:255"}
      
    • The following errors indicate that the server or client TLS certificate is expired. Regenerate the certificate, restart the pods, and try again.
      {"level":"error","ts":1650047047.6682806,"logger":"translator.reconcile-42","caller":"translator/reconciler.go:195","msg":"translation for parent object failed","parent":"istio-ingressgateway-istio-system-cluster1~gloo-mesh~cluster1~internal.gloo.solo.io/v2, Kind=DiscoveredGateway","err":"Gateway istio-ingressgateway.istio-system in cluster cluster1 not found in snapshot.","errVerbose":"Gateway istio-ingressgateway.istio-system in cluster cluster1 not found in snapshot.\n\ttranslator.(*translator).TranslateOutputs.func1:/src/pkg/translator/translator.go:163\n\ttranslator.(*translator).translateParallel:/src/pkg/translator/translator.go:189\n\tsets.(*discoveredGatewaySet).UnsortedList:/src/pkg/api/internal.gloo.solo.io/v2/sets/sets.go:999\n\tsets.(*resourceSet).UnsortedList:/go/pkg/mod/github.com/solo-io/skv2@v0.22.11/contrib/pkg/sets/sets.go:118\n\tsets.(*discoveredGatewaySet).UnsortedList.func1:/src/pkg/api/internal.gloo.solo.io/v2/sets/sets.go:994\n\ttranslator.(*translator).translateParallel.func1:/src/pkg/translator/translator.go:191\n\ttranslator.getValidEastWestIngressGateway:/src/pkg/translator/translator.go:426","stacktrace":"github.com/solo-io/gloo-mesh-enterprise/pkg/translator.(*reconciler).reconcilePrimary.func1\n\t/src/pkg/translator/reconciler.go:195\ngithub.com/solo-io/gloo-mesh-enterprise/pkg/utils/syncutils.(*workQueue).Execute.func1\n\t/src/pkg/utils/syncutils/parallel.go:52"}
      
      {"level":"info","ts":1650046690.815508,"caller":"grpclog/grpclog.go:37","msg":"[core]pickfirstBalancer: UpdateSubConnState: 0xc00111c9d0, {TRANSIENT_FAILURE connection error: desc = \"transport: authentication handshake failed: x509: certificate has expired or is not yet valid: current time 2022-04-15T18:18:10Z is after 2022-04-15T14:28:30Z\"}","system":"grpc","grpc_log":true}
      
  3. For gloo-mesh-agent pods, make sure that the cluster name matches the registered cluster name.

    1. Check the KubernetesCluster resources in the management cluster to get registered cluster names.
        kubectl get kubernetesclusters --context $MGMT_CONTEXT
        
    2. Check that the registered cluster name matches the name in the client certificate that is issued by the root CA, specifically the DNS SAN extension.
    3. If the cluster names do not match, update the KubernetesCluster to have the same name, or re-issue the client certificate with the same name.
  4. If you still have issues, review the Known issues.

Known issues

ca.crt

Although the ca.crt is included in the gloo-mesh-agent certificate secret, the gloo-mesh-agent still expects it to exist separately in the remote cluster. To copy it from the management cluster into the remote clusters, you can run the following command. Make sure to update $CLUSTER_NAME with your remote cluster name.

  CLUSTER_NAME=$REMOTE_CLUSTER
CLUSTER_CONTEXT=$REMOTE_CONTEXT

kubectl get secret gloo-mesh-agent-$CLUSTER_NAME-tls-cert \
  --namespace gloo-mesh \
  --output json \
  --context $CLUSTER_CONTEXT \
  | jq 'del(.metadata.creationTimestamp,.metadata.resourceVersion,.metadata.uid,.data."tls.key",.data."tls.crt",.metadata.annotations)' \
  | sed 's/gloo-mesh-agent-$CLUSTER_NAME-tls-cert/relay-root-tls-secret/' \
  | kubectl apply --context $CLUSTER_CONTEXT -f -