Tyk Operator as Ingress Controller

Introduction

In Kubernetes, the Ingress resource defines routing rules for external HTTP/S traffic to services within a cluster, based on domains or paths. An Ingress Controller, like NGINX or HAProxy, interprets these rules and configures the network infrastructure to route traffic, handling SSL termination and load balancing.

The Tyk Operator builds upon the idea of Kubernetes Ingress by allowing you to reuse existing Ingress definitions while adding advanced API management features like authentication, rate limiting, and monitoring. This approach provides seamless ingress traffic management with powerful API gateway capabilities in a unified solution.

How Tyk Operator Works as an Ingress Controller

When you use Tyk Operator as an Ingress Controller, each “path” defined in your existing Ingress resource is treated as an “API” within Tyk.

Using this Ingress spec as example:

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apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: httpbin-ingress
  annotations:
    kubernetes.io/ingress.class: tyk # Specify Tyk as Ingress Controller
    tyk.io/template: myapideftemplate # The metadata name of the ApiDefinition or TykOasApiDefinition resource in the same namespace
    tyk.io/template-kind: ApiDefinition # Can be "ApiDefinition" (Default) or "TykOasApiDefinition"
spec:
  tls:
    - hosts:
        - myingress.do.poc.tyk.technology
      secretName: httpbin-ingress-tls
  rules:
  - host: myingress.do.poc.tyk.technology
    http:
      paths:
      - path: /httpbin             # Corresponds to API listen path
        pathType: Prefix
        backend:                   # Corresponds to upstream URL
          service:
            name: httpbin
            port:
              number: 8000

Here’s how it works:

• Path Mapping: Tyk Operator will automatically create APIs in Tyk for each path for a specific rule defined in Ingress resource. Just as with traditional Ingress, incoming requests are routed to the correct backend service within the cluster based on the host and paths defined in the Ingress rules.

  In the given example, Tyk Operator is designated as the Ingress Controller for this Ingress resource. Tyk Operator reads this Ingress definition and automatically creates a corresponding API in the Tyk Gateway. The API will have:

  • A custom domain set to myingress.do.poc.tyk.technology, as defined by the host field in the Ingress rule.
  • The TLS certificate from secret httpbin-ingress-tls uploaded to Tyk and certificates field set to the resulting certificate ID.
  • A listen path set to /httpbin, which is defined by the path field in the Ingress rule.
  • An upstream URL set to http://httpbin.default.svc:8000, which corresponds to the backend service defined in the Ingress (httpbin service running on port 8000).

• API Management Through Tyk: At the same time, Tyk allows you to apply API management features by referencing a configuration template. This template is defined using either an ApiDefinition or TykOasApiDefinition resource. These resources provide a reference configuration that includes details on how the API should be managed, such as security policies, traffic controls, and transformations.

  In the given example, there are two important annotations in the Ingress metadata:

    annotations:
      tyk.io/template: myapideftemplate
      tyk.io/template-kind: ApiDefinition
  

  These annotations specify that Tyk Operator should use a resource named myapideftemplate in the same namespace as the reference for API configuration. The tyk.io/template-kind annotation indicates that this reference is of type ApiDefinition. Alternatively, it could be a TykOasApiDefinition, depending on the user’s choice. Tyk Operator detects these annotations and looks for the specified resource in the same namespace. For each path defined in the Ingress, Tyk Operator creates a corresponding API in Tyk by copying the specification from myapideftemplate resource (such as authentication type, rate limiting, etc.) and then updates only the relevant fields like custom domain, certificates, listen path, and upstream URL based on the Ingress spec.

  Note that ApiDefinition or TykOasApiDefinition created for use as a template for Ingress resources should have a special label set so that Tyk Operator would not manage it as ordinary APIs. Here is the required label for ApiDefinition and TykOasApiDefinition respectively:

  Label for ApiDefinition indicating it is a resource template.

    labels:
      template: "true"
  

  Label for TykOasApiDefinition indicating it is a resource template.

    labels:
      tyk.io/ingress-template: "true"
  

  Note that use of TykStreamsApiDefinition as resource template is not supported.

• Automated Resource Handling: Tyk Operator handles the automatic discovery and management of existing Ingress resources, eliminating the need for manual migration of all Ingress rules into API definitions. You can simply define an API configuration template as a TykOasApiDefinition resource or ApiDefinition resource and then let Tyk Operator creates all the APIs from your existing Ingress rules using the referenced resource as template, streamlining the transition process.

  Additionally, the Tyk Operator also handles any changes to the Ingress resources it manages. If an Ingress resource is updated — whether through the addition, removal, or modification of paths in the Ingress rules — Tyk Operator automatically reconfigures the corresponding Tyk APIs to ensure they remain in sync with the updated Ingress configuration. This dynamic updating capability ensures that your API management remains consistent and up-to-date with the latest changes in your Kubernetes environment.

This approach enables you to quickly and easily integrate advanced API management functionalities into your existing Kubernetes environment without needing to change your current configurations significantly.

Configuration Examples

To configure Tyk Operator to handle Ingress resources, specify ingress class as tyk in the Ingress resource. You can also optionally create a ApiDefinition or TykOasApiDefinition resource template that provides default API configurations. This allows Tyk Operator to read the Ingress resource and create API Definition resources based on ingress path and referenced template.

The following sections shows some example of Tyk ApiDefinition or TykOasApiTemplate template and Ingress specification.

HTTP host based and/or path based routing

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apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: httpbin-ingress
  annotations:
    kubernetes.io/ingress.class: tyk # <----------------- REFERENCES TYK INGRESS CONTROLLER
spec:
  rules:
    - host: httpbin.ahmet
      http:
        paths:
          - path: / # host routing: http://httpbin.ahmet/
            pathType: Prefix
            backend:
              service:
                name: httpbin1
                port:
                  number: 8000
          - path: /httpbin # host + path routing: http://httpbin.ahmet/httpbin
            pathType: Prefix
            backend:
              service:
                name: httpbin2
                port:
                  number: 8000
    - http:
        paths:
          - path: /pathonly  # path only routing: http://IPADDRESS/pathonly
            pathType: Prefix
            backend:
              service:
                name: httpbin3
                port:
                  number: 8000
    - host: "*.foo.com" # wildcard
      # curl http://bar.foo.com/httpbin/get === OK Matches based on shared suffix
      # curl http://baz.bar.foo.com/httpbin/get === NOK No match, wildcard only covers a single DNS label
      # curl http://foo.com/httpbin/get === NOK No match, wildcard only covers a single DNS label
      http:
        paths:
          - path: /httpbin
            pathType: Prefix
            backend:
              service:
                name: httpbin4
                port:
                  number: 8000

HTTPS with cert-manager integration

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apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: httpbin-ingress-tls
  annotations:
    kubernetes.io/ingress.class: tyk # <----------------- REFERENCES TYK INGRESS CONTROLLER
    cert-manager.io/cluster-issuer: "letsencrypt-staging" # this annotation indicates the issuer to use.
    acme.cert-manager.io/http01-edit-in-place: "true"
spec:
  tls: 
    - hosts: # < placing a host in the TLS config will determine what ends up in the cert's subjectAltNames
        - myingress.do.poc.tyk.technology
      secretName: httpbin-ingress-tls-secret # < cert-manager will store the created certificate in this secret.
  rules:
    - host: myingress.do.poc.tyk.technology
      http:
        paths:
          - path: /httpbin
            pathType: Prefix
            backend:
              service:
                name: httpbin
                port:
                  number: 8000
---
apiVersion: cert-manager.io/v1
kind: ClusterIssuer
metadata:
  name: letsencrypt-staging
spec:
  acme:
    server: https://acme-staging-v02.api.letsencrypt.org/directory
    email: [email protected]
    privateKeySecretRef:
      name: letsencrypt-staging
    solvers:
      - http01:
          ingress:
            class: tyk
---
apiVersion: v1
kind: Service
metadata:
  name: ingress-gateway
  namespace: tyk
spec:
  ports:
    - name: http
      targetPort: 8000
      port: 80
      protocol: TCP
    - name: https
      targetPort: 443
      port: 443
      protocol: TCP
  selector:
    app: gateway-tyk-stack-tyk-gateway
  type: LoadBalancer
  externalTrafficPolicy: Local

ApiDefinition Template

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apiVersion: tyk.tyk.io/v1alpha1
kind: ApiDefinition
metadata:
 name: myapideftemplate
 labels:
  template: "true" # Instructs Tyk Operator to skip reconciliation for this resource
spec:
 name: foo
 protocol: http
 use_keyless: true
 proxy:
  target_url: http://example.com

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apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: my-ingress
  annotations:
    kubernetes.io/ingress.class: tyk # <----------------- REFERENCES TYK INGRESS CONTROLLER
    tyk.io/template: myapideftemplate # The metadata name of the ApiDefinition or TykOasApiDefinition resource in the same namespace
    tyk.io/template-kind: ApiDefinition # Can be "ApiDefinition" (Default) or "TykOasApiDefinition"
...

TykOasApiDefinition Template

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apiVersion: v1
data:
  test_oas.json: |-
    {
        "info": {
          "title": "OAS Template",
          "version": "1.0.0"
        },
        "openapi": "3.0.3",
        "components": {},
        "paths": {},
        "x-tyk-api-gateway": {
          "info": {
            "name": "OAS Template",
            "state": {
              "active": true
            }
          },
          "upstream": {
            "url": "http://example"
          },
          "server": {
            "listenPath": {
              "value": "/example/",
              "strip": true
            }
          }
        }
      }
kind: ConfigMap
metadata:
  name: cm
  namespace: default
---
apiVersion: tyk.tyk.io/v1alpha1
kind: TykOasApiDefinition
metadata:
  name: oasapitemplate
  labels:
    tyk.io/ingress-template: "true"
spec:
  tykOAS:
    configmapRef:
      name: cm
      namespace: default
      keyName: test_oas.json

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apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: my-ingress
  annotations:
    kubernetes.io/ingress.class: tyk # <----------------- REFERENCES TYK INGRESS CONTROLLER
    tyk.io/template: oasapitemplate # The metadata name of the ApiDefinition or TykOasApiDefinition resource in the same namespace
    tyk.io/template-kind: TykOasApiDefinition # Can be "ApiDefinition" (Default) or "TykOasApiDefinition"
...

Ingress Class

The value of the kubernetes.io/ingress.class annotation identifies the IngressClass that will process Ingress objects.

Tyk Operator by default looks for the value tyk and will ignore all other ingress classes. If you wish to override this default behavior, you may do so by setting the environment variable WATCH_INGRESS_CLASS in the operator manager deployment. See Installing Tyk Operator for further information.

API name

Tyk Ingress Controller will create APIs in Tyk for each path defined for a specific rule in Ingress resource. Each API created inside Tyk will follow a special naming convention as follows:

<ingress_namespace>-<ingress_name>-<hash(Host + Path)>

For example, the following ingress resource will create an ApiDefinition called default-httpbin-ingress-78acd160d inside Tyk’s Gateway. ApiDefinition’s name comes from:

• default: The namespace of this Ingress resource,
• httpbin-ingress: The name of this Ingress resource,
• 78acd160d: Short hash (first 9 characters) of Host ("") and Path (/httpbin). The hash algorithm is SHA256.

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apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
 name: httpbin-ingress
 annotations:
  kubernetes.io/ingress.class: tyk # <----------------- REFERENCES TYK INGRESS CONTROLLER
  tyk.io/template: myapideftemplate # <---------------- REFERENCE TO APIDEFINITION IN SAME NAMESPACE
spec:
 rules:
  - http:
     paths:
      - path: /httpbin
        pathType: Prefix
        backend:
         service:
          name: httpbin
          port:
           number: 8000

Ingress Path Types

Each path in an Ingress must have its own particular path type. Kubernetes offers three types of path types: ImplementationSpecific, Exact, and Prefix. Currently, not all path types are supported. The below table shows the unsupported path types for Sample HTTP Ingress Resource based on the examples in the Kubernetes Ingress documentation.

Please bear in mind that if proxy.strip_listen_path is set to true on API Definition, Tyk strips the listen-path (for example, the listen-path for the Ingress under Sample HTTP Ingress Resource is /httpbin) with an empty string.

The following table shows an example of path matching if the listen-path is set to /httpbin or /httpbin/.