8-ingress

Ingress

If an Ingress Controller has been deployed, one can include Service and Ingress resources within a Control Hub-based deployment. This allows end users to reach the SDC UI over HTTP or HTTPS. An SDC reachable over HTTPS can serve as an Authoring Data Collector.

If the SDC's sdc.properties file is packaged within the SDC image, or is mounted with read/write permissions on an appropriate Volume, one can set these two environment variables within the SDC deployment manifest's container env section, the first of which specifies the URL SDC will be reachable at:

- name: SDC_CONF_SDC_BASE_HTTP_URL
  value: https://<your ingress host>[:<your ingress port>]

- name: SDC_CONF_HTTP_ENABLE_FORWARDED_REQUESTS
  value: true

If sdc.properties is mounted with read-only permissions, these two properties may be set in a configMap as shown in the previous examples.

See sdc.yaml for an example manifest that includes an SDC Deployment, Service and Ingress that will allow SDC to be reached at the base URL of the Ingress Controller.

One can also use a single Ingress Controller to route traffic to multiple SDCs, using either host-based or path-based ingress routing rules.

The following two examples were tested using the ingress-nginx Ingress Controller.

Host-based Routing

In this example, three SDC deployments each use a different hostname as their base URL, with all three hostnames mapped in DNS to the same address (the front end of the Ingress Controller) and host-based routing rules map requests to the appropriate SDC. This approach requires permissions to add alias records to the domain's DNS (the next example does not need any additional permissions).

In the deployment manifests for these three SDCs, sdc1 has this value:

- name: SDC_CONF_SDC_BASE_HTTP_URL
  value: https://sdc1.onefoursix.com

sdc2 has this value:

- name: SDC_CONF_SDC_BASE_HTTP_URL
  value: https://sdc2.onefoursix.com

sdc3 has this value:

- name: SDC_CONF_SDC_BASE_HTTP_URL
  value: https://sdc3.onefoursix.com

These three host names must be added as DNS Aliases that all point to the the external IP of the Load Balancer (by a DNS admin for the domain).

Each SDC has its own Service that specifies a unique NodePort and an Ingress with a host rule. Here is the Ingress for sdc1 with a rule that ensures that requests with the hostname sdc1.onefoursix.com are routed to the sdc1 Service:

apiVersion: extensions/v1beta1
  kind: Ingress
  metadata:
    name: sdc1
    annotations:
      kubernetes.io/ingress.class: nginx
  spec:
    tls:
    - hosts:
      - sdc1.onefoursix.com
      secretName: streamsets-tls
    rules:
    - host: sdc1.onefoursix.com
      http:
        paths:
        - path: /
          backend:
            serviceName: sdc1
            servicePort: 18635

Example manifests for three SDCs that use Host-based routing are in the directory here.

Path-based Routing

Path-based routing relies on a single DNS name for the Ingress, and each SDC will have a unique path appended to the Ingress Controller's base URL. In the deployment manifests for three SDCs using path-based routing:

sdc1 has this value:

- name: SDC_CONF_SDC_BASE_HTTP_URL
  value: https://saturn.onefoursix.com/sdc1/

sdc2 has this value:

- name: SDC_CONF_SDC_BASE_HTTP_URL
  value: https://saturn.onefoursix.com/sdc2/

sdc3 has this value:

- name: SDC_CONF_SDC_BASE_HTTP_URL
  value: https://saturn.onefoursix.com/sdc3/

Ingress is defined using a regular expression to match the request path along with a rewrite-target annotation.

Here is an example of Ingress for sdc1 using path-based routing:

- apiVersion: extensions/v1beta1
  kind: Ingress
  metadata:
    name: sdc1
    namespace: ns1
    annotations:
      kubernetes.io/ingress.class: nginx
      nginx.ingress.kubernetes.io/ssl-redirect: \"false\"
      nginx.ingress.kubernetes.io/rewrite-target: /$2
  spec:
    tls:
    - hosts:
      - saturn.onefoursix.com
      secretName: streamsets-tls
    rules:
    - host: saturn.onefoursix.com
      http:
        paths:
        - path: /sdc1(/|$)(.*)
          backend:
            serviceName: sdc1
            servicePort: 18635

Here is an example of sdc1's UI reached using path-based routing:

Example manifests for three SDCs that use path-based routing are in the directory here.