Centos8平滑升级nginx1.20.2和回滚方案

#下载最新稳定版
[root@centos8 ~]# wget http://nginx.org/download/nginx-1.20.2.tar.gz
[root@centos8 ~]# tar xf nginx-1.20.2.tar.gz 
[root@centos8 ~]# cd nginx-1.20.2
#查看当前使用的版本及编译选项。
[root@centos8 nginx-1.20.2]# nginx -V
nginx version: nginx/1.18.0
built by gcc 8.5.0 20210514 (Red Hat 8.5.0-4) (GCC) 
built with OpenSSL 1.1.1k  FIPS 25 Mar 2021
TLS SNI support enabled
configure arguments: --prefix=/apps/nginx --user=nginx --group=nginx --with-http_ssl_module --with-http_v2_module --with-http_realip_module --with-http_stub_status_module --with-http_gzip_static_module --with-pcre --with-stream --with-stream_ssl_module --with-stream_realip_module
#configure arguments后面是以前编译时的参数。现在编译使用一样的参数
[root@centos8 nginx-1.20.2]# ./configure --prefix=/apps/nginx --user=nginx --group=nginx --with-http_ssl_module --with-http_v2_module --with-http_realip_module --with-http_stub_status_module --with-http_gzip_static_module --with-pcre --with-stream --with-str