Gloo Edge and Istio

You can configure your Gloo Edge gateway with an Istio sidecar to secure the connection between your gateway and the services in your Istio service mesh. The sidecar in your Gloo Edge gateway uses mutual TLS (mTLS) to prove its identity to the services in the mesh and vice versa.

Before you begin

Complete the following tasks before configuring an Istio sidecar for your Gloo Edge gateway:

  1. Create or use an existing cluster that runs Kubernetes a version supported by both your version of Edge and the version of Istio you intend to install.
  2. Install Istio in your cluster. Istio versions 1.14 through 1.20 are supported in Gloo Edge 1.16. See the support matrix for more details.
  3. Set up a service mesh for your cluster. For example, you can use Gloo Mesh Enterprise to configure a service mesh that is based on Envoy and Istio, and that can span across multiple service meshes and clusters.
  4. Install Helm version 3 on your local machine.

Configure the Gloo Edge gateway with an Istio sidecar

Install the Gloo Edge gateway and inject it with an Istio sidecar.

  1. Add the Gloo Edge Helm repo.

    helm repo add gloo
  2. Update the repo.

    helm repo update
  3. Create a value-overrides.yaml file with the following content:

  1. Install or upgrade Gloo Edge.

    Install Gloo Edge with the settings in the value-overrides.yaml file. This command creates the gloo-system namespace and installs the Gloo Edge components into it.

     helm install gloo gloo/gloo --namespace gloo-system --create-namespace -f value-overrides.yaml

    Upgrade Gloo Edge with the settings in the value-overrides.yaml file.

    helm upgrade gloo gloo/gloo --namespace gloo-system -f value-overrides.yaml

  2. Verify your setup.

  3. Verify that your gateway-proxy pod now has three containers.

    kubectl get pods -n gloo-system

    Example output:

    NAME                             READY   STATUS      RESTARTS   AGE
    discovery-6dcc8ddc58-q4zv7       1/1     Running     0          39s
    gateway-certgen-xzr7t            0/1     Completed   0          43s
    gateway-proxy-7bc5c97449-n9498   3/3     Running     0          39s
    gloo-d8cfbf86b-v59j4             1/1     Running     0          39s
    gloo-resource-rollout-hhvf9      0/1     Completed   0          38s
  4. Describe the gateway-proxy pod to verify that the istio-proxy and sds containers are running.

    kubectl describe <gateway-pod-name> -n gloo-system

Congratulations! You have successfully configured an Istio sidecar for your Gloo Edge gateway.

Set up and verify the mTLS connection

To demonstrate that you can connect to your app via mutual TLS (mTLS), you can follow these step to:

  1. Install the httpbin app in your cluster as part of the Istio mesh.

    kubectl label namespace default istio-injection=enabled
    kubectl apply -f

    Example output:

    namespace/default labeled
    serviceaccount/httpbin created
    service/httpbin created
    deployment.apps/httpbin created
  2. Create a virtual service to set up the routing rules for your httpbin app. In the following example, you instruct the Gloo Edge gateway to route incoming requests on the /productpage path to be routed to the productpage service in your cluster.

    kubectl apply -f- <<EOF
    kind: VirtualService
      name: vs
      namespace: gloo-system
        - ''
        - matchers:
          - prefix: /
                name: default-httpbin-8000
                namespace: gloo-system
  3. Test access to httpbin by sending a request to the /headers endpoint. This endpoint returns a response with all of the request headers received by httpbin.

    curl -H "Host:" $(glooctl proxy url)/headers

    A response indicates that httpbin is reachable. However, traffic to the product page upstream is not encrypted with mTLS. We can tell this because the X-Forwarded-Client-Cert header is not present.

      "headers": {
        "Accept": "*/*",
        "Host": "httpbin.default",
        "User-Agent": "curl/7.88.1",
        "X-B3-Sampled": "0",
        "X-B3-Spanid": "b55df4f4d6d75692",
        "X-B3-Traceid": "c048ebc0bb22b1eeb55df4f4d6d75692",
        "X-Forwarded-Host": ""
  4. To require all traffic in the mesh to use mTLS, apply the following STRICT PeerAuthentication policy.

    kubectl apply -f - <<EOF
    apiVersion: ""
    kind: "PeerAuthentication"
      name: "test"
      namespace: "istio-system"
        mode: STRICT
  5. Repeat the same curl request to the product page.

    curl -v -H "Host:" $(glooctl proxy url)/headers 

    The 503 Service Unavailable response is returned because the upstream is not configured for Istio mTLS.

    *   Trying
    * Connected to localhost ( port 32000 (#0)
    > GET /headers HTTP/1.1
    > Host:
    > User-Agent: curl/7.88.1
    > Accept: */*
    < HTTP/1.1 503 Service Unavailable
    < content-length: 95
    < content-type: text/plain
    < date: Tue, 03 Oct 2023 20:15:55 GMT
    < server: envoy
    * Connection #0 to host localhost left intact
      upstream connect error or disconnect/reset before headers. reset reason: connection termination
  6. Use glooctl to configure the upstream for Istio mTLS.

    glooctl istio enable-mtls --upstream default-httpbin-8000
  7. Repeat the same curl request to the product page.

    curl -v -H "Host:" $(glooctl proxy url)/headers 

    This time, the request succeeds because traffic is encrypted using mTLS. Note that httpbin received the X-Forwarded-Client-Cert header, indicating that Istio mTLS has occurred.

         "headers": {
           "Accept": "*/*",
           "Host": "httpbin.default",
           "User-Agent": "curl/7.88.1",
           "X-B3-Sampled": "0",
           "X-B3-Spanid": "b34b0243f9a1e410",
           "X-B3-Traceid": "21dc96a98c29ef48b34b0243f9a1e410",
           "X-Forwarded-Client-Cert": "By=spiffe://cluster.local/ns/default/sa/httpbin;Hash=924e94ed5ff628e797d62acddf37d347ce3df827d5605727bae31a45025bb2a3;Subject=\"\";URI=spiffe://cluster.local/ns/gloo-system/sa/gateway-proxy",
           "X-Forwarded-Host": ""

If you use Gloo Mesh Enterprise for your service mesh, you can configure your Gloo Edge upstream resource to point to the Gloo Mesh ingress-gateway. For a request to reach the httpbin app in remote workload clusters, your virtual service must be configured to route traffic to the Gloo Mesh east-west gateway.