Testing Istio mutual TLS authentication
Through this task, you will learn how to:
Verify the Istio mutual TLS Authentication setup
Manually test the authentication
Before you begin
This task assumes you have a Kubernetes cluster:
- Installed Istio with mutual TLS authentication by following the Istio installation task. Note to choose “enable Istio mutual TLS Authentication feature” at step 5 in “Installation steps”.
Verifying Istio’s mutual TLS authentication setup
The following commands assume the services are deployed in the default namespace. Use the parameter -n yournamespace to specify a namespace other than the default one.
Verifying Istio CA
Verify the cluster-level CA is running:
kubectl get deploy -l istio=istio-ca -n istio-system
NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE istio-ca 1 1 1 1 1m
Istio CA is up if the “AVAILABLE” column is 1.
Verifying service configuration
Verify AuthPolicy setting in ConfigMap.
kubectl get configmap istio -o yaml -n istio-system | grep authPolicy | head -1
Istio mutual TLS authentication is enabled if the line
authPolicy: MUTUAL_TLSis uncommented (doesn’t have a
Testing the authentication setup
When running Istio with mutual TLS authentication turned on, you can use curl in one service’s Envoy to send request to other services. For example, after starting the Bookinfo sample application you can ssh into the Envoy container of
productpage service, and send request to other services by curl.
There are several steps:
- get the productpage pod name
kubectl get pods -l app=productpage
NAME READY STATUS RESTARTS AGE productpage-v1-4184313719-5mxjc 2/2 Running 0 23h
Make sure the pod is “Running”.
- ssh into the Envoy container
kubectl exec -it productpage-v1-4184313719-5mxjc -c istio-proxy /bin/bash
- make sure the key/cert is in /etc/certs/ directory
cert-chain.pem key.pem root-cert.pem
Note that cert-chain.pem is Envoy’s cert that needs to present to the other side. key.pem is Envoy’s private key paired with cert-chain.pem. root-cert.pem is the root cert to verify the other side’s cert. Currently we only have one CA, so all Envoys have the same root-cert.pem.
- make sure ‘curl’ is installed by
If curl is installed, you should see something like
curl: try 'curl --help' or 'curl --manual' for more information
Note: by default istio proxy image does not have curl installed to make the image compact. However, the proxy debug image does have curl, please add –debug flag during kube-inject, i.e.,
kubectl apply -f <(istioctl kube-inject --debug -f samples/bookinfo/kube/bookinfo.yaml)
and start over.
- send requests to another service, for example, details.
curl https://details:9080/details/0 -v --key /etc/certs/key.pem --cert /etc/certs/cert-chain.pem --cacert /etc/certs/root-cert.pem -k
... error fetching CN from cert:The requested data were not available. ... < HTTP/1.1 200 OK < content-type: text/html; charset=utf-8 < content-length: 1867 < server: envoy < date: Thu, 11 May 2017 18:59:42 GMT < x-envoy-upstream-service-time: 2 ...
The service name and port are defined here.
Note that Istio uses Kubernetes service account as service identity, which offers stronger security than service name (refer here for more information). Thus the certificates used in Istio do not have service name, which is the information that curl needs to verify server identity. As a result, we use curl option ‘-k’ to prevent the curl client from aborting when failing to find and verify the server name (i.e., productpage.ns.svc.cluster.local) in the certificate provided by the server.
Please check secure naming here for more information about how the client verifies the server’s identity in Istio.
What we are demonstrating and verifying above is that the server accepts the connection from the client. Try not giving the client
--cert and observe you are not allowed to connect and you do not get an HTTP 200.
- Learn more about the design principles behind Istio’s automatic mTLS authentication between all services in this blog.