8 nginx smooth upgrade
8.1 Nginx-master signal
1. The master does not process requests, but allocates worker processes and is responsible for restart, hot deployment, reloading and other functions.
2.Master defines the number of workers to start based on worker_processes
3. After the worker runs, the master is in a suspended state, waiting for a signal
4. You can send kill, or nginx -s parameter to send a signal
signal collection
| nginx -s corresponding parameters |
Signal |
meaning |
| stop |
TERM |
Force shutdown of entire service |
| null |
INT |
Force shutdown of entire service |
| quit |
QUIT |
Gracefully shut down the entire service |
| reopen |
USR1 |
Turn logging back on |
| reload |
HUP |
Reread the configuration file and exit the old worker gracefully |
| null |
USR2 |
Smooth upgrade to new version |
| null |
WINCH |
Shut down workers gracefully (must be used during hot updates) |
8.2 Smooth upgrade (hot deployment)
Hot deployment refers to the new application directly replacing the old application without restarting or shutting down the process.
热部署大致流程
1.备份旧的二进制文件
2.编译安装新的二进制文件，覆盖旧的二进制文件
3.发送USR2信号给旧master进程
4.发送WINCH信号给旧master进程
5.发送QUIT信号给旧master进程8.3 Pitfalls of hot deployment
If no new master process appears after sending the kill -USR2 signal
This is because: the old nginx must be started with an absolute path and then send the kill -USR2 signal
See picture for detailed explanation
8.4 Specific operations of hot deployment
1.备份旧版本的nginx二进制文件
[root@test1 sbin]# mv nginx nginx.old
[root@test1 sbin]# ls
nginx.old
2.检查旧版本nginx的编译参数
[root@test1 sbin]# nginx.old -V
nginx version: nginx/1.14.0
3.编译安装新版本nginx
#下载新nginx源码
[root@test1 Learn_Nginx]# wget http://nginx.org/download/nginx-1.17.8.tar.gz
#编译安装新版本nginx
[root@test1 Learn_Nginx]# tar -zxf nginx-1.17.8.tar.gz
#开始编译
[root@test1 Learn_Nginx]# cd nginx-1.17.8/
[root@test1 nginx-1.17.8]# ./configure --prefix=/home/Learn_Nginx/nginx/ --with-http_ssl_module --with-http_flv_module --with-http_gzip_static_module --with-http_stub_status_module --with-threads --with-file-aio
#编译安装
[root@test1 nginx-1.17.8]# make && make install
4.此时发现已存在2个版本nginx程序
[root@test1 sbin]# ls
nginx nginx.old
5.替换旧的nginx可执行文件
[root@test1 sbin]# cp -a /home/Learn_Nginx/nginx-1.17.8/objs/nginx /home/Learn_Nginx/nginx/sbin/
cp：是否覆盖"/home/Learn_Nginx/nginx/sbin/nginx"？ y
5.1检查旧的nginx进程，请注意，这里用绝对路径启动nginx
请注意，这里用绝对路径启动nginx
请注意，这里用绝对路径启动nginx
例如
/home/Learn_Nginx/nginx/sbin/nginx
注意这里的PID和PPID（pid是当前进程的id号，ppid是启动该进程的pid，也就是父ID，可知该pid由谁启动）
[root@test1 sbin]# ps -ef|grep nginx
root 20311 1 0 15:12 ? 00:00:00 nginx: master process nginx
nobody 20312 20311 0 15:12 ? 00:00:00 nginx: worker process
root 20314 13589 0 15:12 pts/0 00:00:00 grep --color=auto nginx
6.发送USR2信号给旧版本主进程，使得nginx旧版本停止接收请求，切换为新nginx版本
[root@test1 sbin]# kill -USR2 `cat ../logs/nginx.pid `
7.检查此时的nginx进程
nginx-master首先会重命名pid文件，在文件后面添加.oldbin后缀
然后会再启动一个新的master进程以及worker，且使用的是新版Nginx
nginx能够自动将新来的请求，过度到新版master进程下，实现平滑过度
#可以发现新的master进程由旧master启动，由PPID可看出
[root@test1 sbin]# ps -ef|grep nginx
root 20311 1 0 15:12 ? 00:00:00 nginx: master process nginx
nobody 20312 20311 0 15:12 ? 00:00:00 nginx: worker process
root 20335 20311 0 15:13 ? 00:00:00 nginx: master process nginx
nobody 20336 20335 0 15:13 ? 00:00:00 nginx: worker process
root 20338 13589 0 15:13 pts/0 00:00:00 grep --color=auto nginx
[root@test1 sbin]# ls ../logs/
access.log error.log nginx.pid nginx.pid.oldbin
8.发送WINCH信号给旧master进程，优雅的关闭旧worker进程
[root@test1 sbin]# kill -WINCH `cat ../logs/nginx.pid.oldbin`
#再次检查进程情况，旧master的worker已经关闭了，旧master不会自己退出，用作版本回退
[root@test1 sbin]# ps -ef|grep nginx
root 20311 1 0 15:12 ? 00:00:00 nginx: master process nginx
root 20335 20311 0 15:13 ? 00:00:00 nginx: master process nginx
nobody 20336 20335 0 15:13 ? 00:00:00 nginx: worker process
root 20607 13589 0 15:25 pts/0 00:00:00 grep --color=auto nginx
9.如果你觉得没问题了，可以关闭旧master进程
[root@test1 sbin]# ps -ef|grep nginx
root 20335 1 0 15:13 ? 00:00:00 nginx: master process nginx
nobody 20336 20335 0 15:13 ? 00:00:00 nginx: worker process
root 20665 13589 0 15:28 pts/0 00:00:00 grep --color=auto nginx