说明文档：https://kubernetes.github.io/ingress-nginx/user-guide/nginx-configuration/configmap/
将键值对添加到config-map的data部分。例如：
data: map-hash-bucket-size: "128" ssl-protocols: SSLv2
1）我们看到yaml文件里引用configmap名为：nginx-configuration
2）修改对应namespace下该文件后apply生效。
kind: ConfigMap
apiVersion: v1
data:
client-header-buffer-size: 20m
compute-full-forwarded-for: "true"
forwarded-for-header: X-Forwarded-For
large-client-header-buffers: 4 1024k
proxy-body-size: 50m
use-forwarded-headers: "true"
metadata:
name: nginx-ingress-controller
namespace: default
labels:
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
原文：https://www.cnblogs.com/Dev0ps/p/12622979.html