kubernetes-subpath用法（把文件挂载在已存在的目录下，不覆盖原目录）

以ngxin的配置文件为例子：

nginx-deployment.yaml ：

apiVersion: v1
kind: ConfigMap
metadata:
name: nginx-cm
data:
nginx.conf: |
user nginx;
worker_processes 4;
worker_rlimit_nofile 48127;
error_log /var/log/nginx/error.log warn;
pid /var/run/nginx.pid;
events {
multi_accept on;
worker_connections 16384;
use epoll;
}
http {
include /etc/nginx/mime.types;
default_type application/octet-stream;

log_format main '$remote_addr - $remote_user [$time_local] "$request" '
'$status $body_bytes_sent "$http_referer" '
'"$http_user_agent" "$http_x_forwarded_for"';
access_log /var/log/nginx/access.log main;
sendfile on;
#tcp_nopush on;
keepalive_timeout 65;
#gzip on;
#include /etc/nginx/conf.d/*.conf;
server {
listen 80;
server_name localhost;
location / {
root /usr/share/nginx/html;
index index.html index.htm;
}
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root /usr/share/nginx/html;
}
location /nginx_status {
#allow 127.0.0.1;
#deny all;
access_log off;
stub_status on;
}
}
} 

---

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
name: nginx
spec:
replicas: 1
template:
metadata:
labels:
app: nginx
spec:
nodeSelector:
kubernetes.io/hostname: 192.168.5.86
containers:
- name: nginx
image: nginx:latest
imagePullPolicy: IfNotPresent
volumeMounts:
- mountPath: /etc/nginx/nginx.conf
name: nginx-config
subPath: etc/nginx/nginx.conf
ports:
- containerPort: 80
volumes:
- name: nginx-config
configMap:
name: nginx-cm
items:
- key: nginx.conf
path: etc/nginx/nginx.conf

　　

创建pod:

kubectl create -f ./nginx-deployment.yaml

查看nginx的目录的旧文件是否还在：

$ kubectl exec -it nginx-6b76cd9c54-fb2q8 -- ls /etc/nginx/
conf.d		koi-utf  mime.types  nginx.conf   uwsgi_params
fastcgi_params	koi-win  modules     scgi_params  win-utf

　　

查看nginx.conf是否被更新了：

$ kubectl exec -it nginx-6b76cd9c54-fb2q8 -- cat /etc/nginx/nginx.conf
user nginx;
worker_processes 4;
worker_rlimit_nofile 48127;
error_log /var/log/nginx/error.log warn;
pid /var/run/nginx.pid;
events {
multi_accept on;
worker_connections 16384;
use epoll;
}
http {
include /etc/nginx/mime.types;
default_type application/octet-stream;

log_format main '$remote_addr - $remote_user [$time_local] "$request" '
'$status $body_bytes_sent "$http_referer" '
'"$http_user_agent" "$http_x_forwarded_for"';
access_log /var/log/nginx/access.log main;
sendfile on;
#tcp_nopush on;
keepalive_timeout 65;
#gzip on;
#include /etc/nginx/conf.d/*.conf;
server {
listen 80;
server_name localhost;
location / {
root /usr/share/nginx/html;
index index.html index.htm;
}
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root /usr/share/nginx/html;
}
location /nginx_status {
#allow 127.0.0.1;
#deny all;
access_log off;
stub_status on;
}
}
}

　　

实例配置：