终于在 Nginx Ingress Controller 的官方帮助文档 Advanced Configuration with Annotations 中找到一个注解（annotation）解决了这个问题，它就是 nginx.org/redirect-to-https: "true"

Annotation: nginx.org/redirect-to-https
ConfigMap Key redirect-to-https
Description Sets the 301 redirect rule based on the value of the http_x_forwarded_proto header on the server block to force incoming traffic to be over HTTPS. Useful when terminating SSL in a load balancer in front of the Ingress controller

操作步骤：
1）在 cnblogs-ingress.yaml 中 annotations 下面添加 nginx.org/redirect-to-https: "true"

apiVersion: extensions/v1beta1 
kind: Ingress
metadata:
  name: cnblogs-ingress
  annotations:
    kubernetes.io/ingress.class: nginx
    nginx.org/redirect-to-https: "true"
spec:
  rules:
  - host: q.cnblogs.com
    http:
      paths:
        - backend:
            serviceName: q-web
            servicePort: 80

2）更新 ingress 配置

kubectl apply -f cnblogs-ingress.yaml

3）更新 nginx-ingress

kubectl rollout restart daemonset/nginx-ingress -n nginx-ingress && \
kubectl rollout status daemonset/nginx-ingress -n nginx-ingress

4）查看 inginx 容器中的配置

kubectl exec -it daemonset/nginx-ingress -n nginx-ingress cat /etc/nginx/conf.d/production-cnblogs-ingress.conf

发现 proxy_set_header X-Forwarded-Proto $scheme; 变成了 proxy_set_header X-Forwarded-Proto https; ，并且增加了下面的 http 重定向 https 的配置。

if ($http_x_forwarded_proto = 'http') {
    return 301 https://$host$request_uri;
}

nginx-ingress 自己完成了基于 X-Forwarded-Proto 的 http 重定向到 https 的操作，应用都不需要自己处理了。