Updated on 2024-01-04 GMT+08:00

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

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

  1. Use kubectl to connect to the cluster. For details, see Connecting to a Cluster Using kubectl.
  2. 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.

  3. 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 successfully and the workload is accessible.

    NAME             HOSTS     ADDRESS          PORTS   AGE
    ingress-test     *         121.**.**.**     80      10s

  4. 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.