Using kubectl to Create an Nginx Ingress

Scenario

This section uses an Nginx workload as an example to describe how to create an Nginx ingress using kubectl.

Prerequisites

The NGINX Ingress Controller add-on has been installed in a cluster. For details, see Installing the Add-on.
An ingress provides network access for backend workloads. Ensure that a workload is available in a cluster. If no workload is available, deploy a workload by referring to Creating a Deployment, Creating a StatefulSet, or Creating a DaemonSet.
A ClusterIP or NodePort Service has been configured for the workload. For details about how to configure the Service, see ClusterIP or NodePort.

Ingress Description of networking.k8s.io/v1

In CCE clusters of v1.23 or later, the ingress version is switched to networking.k8s.io/v1.

Compared with v1beta1, v1 has the following differences in parameters:

The ingress type is changed from kubernetes.io/ingress.class in annotations to spec.ingressClassName.
The format of backend is changed.
The pathType parameter must be specified for each path. The options are as follows:
- ImplementationSpecific: The matching method depends on Ingress Controller. The matching method defined by ingress.beta.kubernetes.io/url-match-mode is used in CCE, which is the same as v1beta1.
- Exact: exact matching of the URL, which is case-sensitive.
- Prefix: matching based on the URL prefix separated by a slash (/). The match is case-sensitive, and elements in the path are matched one by one. A path element refers to a list of labels in the path separated by a slash (/).

Creating an Nginx Ingress

Use kubectl to connect to the cluster. For details, see Connecting to a Cluster Using kubectl.

Create a YAML file named ingress-test.yaml. The file name can be customized.

vi ingress-test.yaml

Starting from cluster v1.23, the ingress version is switched from networking.k8s.io/v1beta1 to networking.k8s.io/v1. For details about the differences between v1 and v1beta1, see Ingress Description of networking.k8s.io/v1.

The following uses HTTP as an example to describe how to configure the YAML file:

For clusters of v1.23 or later:

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: ingress-test
spec:
  rules:
    - host: ''
      http:
        paths:
          - path: /
            backend:
              service:
                name: <your_service_name>  # Replace it with the name of your target Service.
                port:
                  number: <your_service_port>  # Replace it with the port number of your target Service.
            property:
              ingress.beta.kubernetes.io/url-match-mode: STARTS_WITH
            pathType: ImplementationSpecific
  ingressClassName: nginx   # Nginx ingress is used.

For clusters of v1.21 or earlier:

apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
  name: ingress-test
  namespace: default
  annotations:
    kubernetes.io/ingress.class: nginx   # Nginx ingress is used.
spec:
  rules:
    - host: ''
      http:
        paths:
          - path: '/'
            backend:
              serviceName: <your_service_name>  # Replace it with the name of your target Service.
              servicePort: <your_service_port>  # Replace it with the port number of your target Service.

**Table 1** Key parameters
Parameter	Mandatory	Type	Description
kubernetes.io/ingress.class	Yes (only for clusters of v1.21 or earlier)	String	nginx: indicates that Nginx ingress is used. This option cannot be used if the nginx-ingress add-on is not installed. This parameter is mandatory when an ingress is created by calling the API.
ingressClassName	Yes (only for clusters of v1.23 or later)	String	nginx: indicates that Nginx ingress is used. This option cannot be used if the nginx-ingress add-on is not installed. This parameter is mandatory when an ingress is created by calling the API.
host	No	String	Domain name for accessing the Service. By default, this parameter is left blank, and the domain name needs to be fully matched. Ensure that the domain name has been registered and archived. Once a domain name rule is configured, you must use the domain name for access.
path	Yes	String	User-defined route path. All external access requests must match host and path. NOTE: The access path matching rule of Nginx ingress is based on the path prefix separated by the slash (/) and is case-sensitive. If the subpath separated by a slash (/) matches the prefix, the access is normal. However, if the prefix is only a part of the character string in the subpath, the access is not matched. For example, if the URL is set to /healthz, /healthz/v1 is matched, but /healthzv1 is not matched. The access path added here must exist in the backend application. Otherwise, the forwarding fails. For example, the default access URL of the Nginx application is /usr/share/nginx/html. When adding /test to the ingress forwarding policy, ensure the access URL of your Nginx application contains /usr/share/nginx/html/test. Otherwise, error 404 will be returned.
ingress.beta.kubernetes.io/url-match-mode	No	String	Route matching policy. Default: STARTS_WITH (prefix match) Options: EQUAL_TO: exact match STARTS_WITH: prefix match
pathType	Yes	String	Path type. This field is supported only by clusters of v1.23 or later. ImplementationSpecific: The matching method depends on Ingress Controller. The matching method defined by ingress.beta.kubernetes.io/url-match-mode is used in CCE. Exact: exact matching of the URL, which is case-sensitive. Prefix: prefix matching, which is case-sensitive. With this method, the URL path is separated into multiple elements by slashes (/) and the elements are matched one by one. If each element in the URL matches the path, the subpaths of the URL can be routed normally. NOTE: During prefix matching, each element must be exactly matched. If the last element of the URL is the substring of the last element in the request path, no matching is performed. For example, /foo/bar matches /foo/bar/baz but does not match /foo/barbaz. When elements are separated by slashes (/), if the URL or request path ends with a slash (/), the slash (/) at the end is ignored. For example, /foo/bar matches /foo/bar/. See examples of ingress path matching.

Create an ingress.
kubectl create -f ingress-test.yaml

If information similar to the following is displayed, the ingress has been created.
```
ingress/ingress-test created
```
View the created ingress.

kubectl get ingress

If information similar to the following is displayed, the ingress has been created and the workload is accessible.
```
NAME             HOSTS     ADDRESS          PORTS   AGE
ingress-test     *         121.**.**.**     80      10s
```
Enter http://121.**.**.**:80 in the address box of the browser to access the workload (for example, Nginx workload).
121.**.**.** indicates the IP address of the unified load balancer.