This topic provides answers to some frequently asked questions about Ingresses.

Which Transport Layer Security (SSL/TLS) protocol versions are supported by Ingresses?

By default, ingress-nginx supports only TLS 1.2. If the TLS protocol version that is used by a browser or mobile client is earlier than TLS 1.2, errors occur during handshakes between the client and ingress-nginx.

If you want ingress-nginx to support more TLS protocol versions, run the following commands to add required configurations to the nginx-configuration ConfigMap in the kube-system namespace. For more information, see TLS/HTTPS.
ssl-ciphers: "ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384:DHE-RSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA:ECDHE-RSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES256-SHA256:AES128-GCM-SHA256:AES256-GCM-SHA384:AES128-SHA256:AES256-SHA256:AES128-SHA:AES256-SHA:DES-CBC3-SHA"
ssl-protocols: "TLSv1 TLSv1.1 TLSv1.2 TLSv1.3"

Does Ingress pass through Layer 7 request headers?

By default, ingress-nginx passes through Layer 7 request headers. However, request headers that do not conform to HTTP rules are filtered out before they are forwarded to the backend Services. For example, the Mobile Version request header is filtered out. If you do not want to filter out these request headers, run the following command to add the required configurations to the nginx-configuration ConfigMap. For more information, see ConfigMap.
enable-underscores-in-headers: true

Can ingress-nginx forward requests to HTTPS Services at the backend?

To enable ingress-nginx to forward requests to HTTPS Services at the backend, run the following command to add the required annotations to the Ingress configuration:
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: xxxx
  annotations:
    # Note: You must specify the backend protocol as HTTPS to enable ingress-nginx to forward requests to HTTPS Services at the backend.
    nginx.ingress.kubernetes.io/backend-protocol: "HTTPS"

Does Ingress pass through client IP addresses at Layer 7?

By default, ingress-nginx passes through client IP addresses at Layer 7 based on the configurations of X-Forward-For and X-Real-IP. However, if X-Forward-For and X-Real-IP are specified in a request header from a client, the backend server cannot obtain the real client IP address.

Run the following command to modify the nginx-configuration ConfigMap in the kube-system namespace. This allows ingress-nginx to pass through client IP addresses at Layer 7.
compute-full-forwarded-for: "true"
forwarded-for-header: "X-Forwarded-For"
use-forwarded-headers: "true"

For more information, see Configure an ACK Ingress to pass through client IP addresses.

Does nginx-ingress-controller support HTTP Strict Transport Security (HSTS)?

By default, HSTS is enabled for nginx-ingress-controller. When a browser sends out a plain HTTP request for the first time, the response header from the backend server (with HSTS enabled) contains Non-Authoritative-Reason: HSTS. This indicates that the backend server supports HSTS. If the client also supports HSTS, the client will continue to send HTTPS requests after the first access attempt succeeds. The response body from the backend server contains the status code 307 Internal Redirect, as shown in the following figure.1
If you do not want the client requests to be forwarded to HTTPS Services at the backend, you can disable HSTS for nginx-ingress-controller. For more information, see HSTS.
Note By default, the HSTS configuration is cached by browsers. You must manually delete the browser cache after you disable HSTS for nginx-ingress-controller.

Which rewrite rules are supported by ingress-nginx?

Only simple rewrite rules are supported by ingress-nginx. For more information, see Rewrite. If you want to configure complex rewrite rules, use the following methods:
  • configuration-snippet: Add this annotation to the location configuration of an Ingress. For more information, see Configuration snippet.
  • server-snippet: Add this annotation to the server configuration of an Ingress. For more information, see Server snippet.
You can use other code snippets to add global configurations, as shown in the following figure. For more information, see main-snippet.2

How do I fix the issue that Log Service cannot parse logs as normal after ingress-nginx-controller is upgraded?

The ingress-nginx-controller component has two commonly used versions: ingress-nginx-controller 0.20 and 0.30. The default log format of ingress-nginx-controller 0.20 is different from that of ingress-nginx-controller 0.30. Therefore, after you upgrade from ingress-nginx-controller 0.20 to 0.30 on the Add-ons page in the console, the Ingress dashboard may not show the actual access statistics to the backend Services when you perform canary releases or blue-green releases for an Ingress.

To fix the issue, perform the following steps to update the nginx-configuration ConfigMap and the configuration of k8s-nginx-ingress.

  1. Update the nginx-configuration ConfigMap.
    • If you have not modified the nginx-configuration ConfigMap, copy the following content to a file named nginx-configuration.yaml and run the kubectl apply -f nginx-configuration.yaml command to deploy the file.
      apiVersion: v1
kind: ConfigMap
data:
  allow-backend-server-header: "true"
  enable-underscores-in-headers: "true"
  generate-request-id: "true"
  ignore-invalid-headers: "true"
  log-format-upstream: $remote_addr - [$remote_addr] - $remote_user [$time_local] "$request" $status $body_bytes_sent "$http_referer" "$http_user_agent" $request_length $request_time [$proxy_upstream_name] $upstream_addr $upstream_response_length $upstream_response_time $upstream_status $req_id $host [$proxy_alternative_upstream_name]
  max-worker-connections: "65536"
  proxy-body-size: 20m
  proxy-connect-timeout: "10"
  reuse-port: "true"
  server-tokens: "false"
  ssl-redirect: "false"
  upstream-keepalive-timeout: "900"
  worker-cpu-affinity: auto
metadata:
  labels:
    app: ingress-nginx
  name: nginx-configuration
  namespace: kube-system
    • If you have modified the nginx-configuration ConfigMap, run the following command to update the configuration. This ensures that your previous modifications are not overwritten.
      kubectl edit configmap nginx-configuration -n kube-system

    Add [$proxy_alternative_upstream_name] to the end of the log-format-upstream field, save the changes, and then exit.

  2. Update the configuration of k8s-nginx-ingress.
    Copy the following content to a file named k8s-nginx-ingress.yaml and run the kubectl apply -f k8s-nginx-ingress.yaml command to deploy the file.
    apiVersion: log.alibabacloud.com/v1alpha1
kind: AliyunLogConfig
metadata:
    namespace: kube-system
  # your config name, must be unique in you k8s cluster
  name: k8s-nginx-ingress
spec:
  # logstore name to upload log
  logstore: nginx-ingress
  # product code, only for k8s nginx ingress
  productCode: k8s-nginx-ingress
  # logtail config detail
  logtailConfig:
    inputType: plugin
    # logtail config name, should be same with [metadata.name]
    configName: k8s-nginx-ingress
    inputDetail:
      plugin:
        inputs:
        - type: service_docker_stdout
          detail:
            IncludeLabel:
              io.kubernetes.container.name: nginx-ingress-controller
            Stderr: false
            Stdout: true
        processors:
        - type: processor_regex
          detail:
            KeepSource: false
            Keys:
            - client_ip
            - x_forward_for
            - remote_user
            - time
            - method
            - url
            - version
            - status
            - body_bytes_sent
            - http_referer
            - http_user_agent
            - request_length
            - request_time
            - proxy_upstream_name
            - upstream_addr
            - upstream_response_length
            - upstream_response_time
            - upstream_status
            - req_id
            - host
            - proxy_alternative_upstream_name
            NoKeyError: true
            NoMatchError: true
            Regex: ^(\S+)\s-\s\[([^]]+)]\s-\s(\S+)\s\[(\S+)\s\S+\s"(\w+)\s(\S+)\s([^"]+)"\s(\d+)\s(\d+)\s"([^"]*)"\s"([^"]*)"\s(\S+)\s(\S+)+\s\[([^]]*)]\s(\S+)\s(\S+)\s(\S+)\s(\S+)\s(\S+)\s*(\S*)\s*\[*([^]]*)\]*. *
            SourceKey: content