4.5 KiB
title | description | weight | keywords | owner | test | ||
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Kubernetes Ingress | Describes how to configure a Kubernetes Ingress object to expose a service outside of the service mesh. | 40 |
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istio/wg-networking-maintainers | yes |
This task describes how to configure Istio to expose a service outside of the service mesh cluster, using the Kubernetes Ingress Resource.
{{< tip >}} Using a Gateway, rather than Ingress, is recommended to make use of the full feature set that Istio offers, such as rich traffic management and security features. {{< /tip >}}
Before you begin
Follow the instructions in the Before you begin and Determining the ingress IP and ports sections of the Ingress Gateways task.
Configuring ingress using an Ingress resource
A Kubernetes Ingress Resources exposes HTTP and HTTPS routes from outside the cluster to services within the cluster.
Let's see how you can configure a Ingress
on port 80 for HTTP traffic.
-
Create an
Ingress
resource:{{< text bash >}} $ kubectl apply -f - <<EOF apiVersion: networking.k8s.io/v1 kind: Ingress metadata: annotations: kubernetes.io/ingress.class: istio name: ingress spec: rules:
- host: httpbin.example.com
http:
paths:
- path: /status pathType: Prefix backend: service: name: httpbin port: number: 8000 EOF {{< /text >}}
The
kubernetes.io/ingress.class
annotation is required to tell the Istio gateway controller that it should handle thisIngress
, otherwise it will be ignored. - host: httpbin.example.com
http:
paths:
-
Access the httpbin service using curl:
{{< text bash >}} $ curl -s -I -HHost:httpbin.example.com "http://$INGRESS_HOST:$INGRESS_PORT/status/200" HTTP/1.1 200 OK server: istio-envoy ... {{< /text >}}
Note that you use the
-H
flag to set the Host HTTP header to "httpbin.example.com". This is needed because theIngress
is configured to handle "httpbin.example.com", but in your test environment you have no DNS binding for that host and are simply sending your request to the ingress IP. -
Access any other URL that has not been explicitly exposed. You should see an HTTP 404 error:
{{< text bash >}} $ curl -s -I -HHost:httpbin.example.com "http://$INGRESS_HOST:$INGRESS_PORT/headers" HTTP/1.1 404 Not Found ... {{< /text >}}
Next Steps
TLS
Ingress
supports specifying TLS settings. This is supported by Istio, but the referenced Secret
must exist in the namespace of the istio-ingressgateway
deployment (typically istio-system
). cert-manager can be used to generate these certificates.
Specifying path type
By default, Istio will treat paths as exact matches, unless they end in /*
or .*
, in which case they will become prefix matches. Other regular expressions are not supported.
In Kubernetes 1.18, a new field, pathType
, was added. This allows explicitly declaring a path as Exact
or Prefix
.
Specifying IngressClass
In Kubernetes 1.18, a new resource, IngressClass
, was added, replacing the kubernetes.io/ingress.class
annotation on the Ingress
resource. If you are using this resource, you will need to set the controller
field to istio.io/ingress-controller
. For example:
{{< text yaml >}} apiVersion: networking.k8s.io/v1 kind: IngressClass metadata: name: istio spec: controller: istio.io/ingress-controller
apiVersion: networking.k8s.io/v1 kind: Ingress metadata: name: ingress spec: ingressClassName: istio rules:
- host: httpbin.example.com
http:
paths:
- path: / pathType: Prefix backend: service: name: httpbin port: number: 8000 {{< /text >}}
Cleanup
Delete the Ingress
configuration, and shutdown the [httpbin]({{< github_tree >}}/samples/httpbin) service:
{{< text bash >}} $ kubectl delete ingress ingress $ kubectl delete --ignore-not-found=true -f @samples/httpbin/httpbin.yaml@ {{< /text >}}