因为涉及到两个域名以及两个 ssl 证书，采用了比较笨的方法。两个配置文件。
a.com.conf

server {
server_name www.a.com a.com;

#301 配置
if ($host != 'www.b.com') {
rewrite ^/(.*)$ https://www.b.com/$1 permanent;
}

#其他的配置参数

}

server {
listen 80;
listen 443 ssl;

# SSL 证书配置
ssl_certificate /etc/letsencrypt/live/www.a.com/fullchain.pem;
ssl_certificate_key /etc/letsencrypt/live/www.a.com/privkey.pem;

#ssl_certificate /etc/letsencrypt/live/www.b.com/fullchain.pem;
#ssl_certificate_key /etc/letsencrypt/live/www.b.com/privkey.pem;

ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
ssl_session_cache shared:SSL:10m;
ssl_session_timeout 10m;

server_name www.a.com;

root /srv/www/a.com/public_html;
access_log /var/log/www/a.com.access.log;
error_log /var/log/www/a.com.error.log;

location / {
index index.php index.html index.htm;
if (-f $request_filename) {
expires 30d;
break;
}
try_files $uri $uri/ /index.php?$args;
}
# Add trailing slash to */wp-admin requests.
rewrite /wp-admin$ $scheme://$host$uri/ permanent;

location /nginx-status {
stub_status on;
access_log off;
}
location ~ \.php$ {
fastcgi_pass unix:/var/run/php/php7.0-fpm.a.com.sock;
fastcgi_index index.php;
fastcgi_param SCRIPT_FILENAME /srv/www/a.com/public_html$fastcgi_script_name;
fastcgi_param PATH_INFO $fastcgi_script_name;
include fastcgi_params;
}
}

-----------
b.com.conf


server {
listen 80;
server_name www.b.com b.com www.a.com a.com;
return 301 https://www.b.com$request_uri;

}


server {
listen 80;
listen 443 ssl;

# SSL 证书配置
#ssl_certificate /etc/letsencrypt/live/www.a.com/fullchain.pem;
#ssl_certificate_key /etc/letsencrypt/live/www.a.com/privkey.pem;

ssl_certificate /etc/letsencrypt/live/www.b.com/fullchain.pem;
ssl_certificate_key /etc/letsencrypt/live/www.b.com/privkey.pem;

ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
ssl_session_cache shared:SSL:10m;
ssl_session_timeout 10m;

server_name www.b.com;

root /srv/www/a.com/public_html;
access_log /var/log/www/a.com.access.log;
error_log /var/log/www/a.com.error.log;

location / {
index index.php index.html index.htm;
if (-f $request_filename) {
expires 30d;
break;
}
try_files $uri $uri/ /index.php?$args;
}
# Add trailing slash to */wp-admin requests.
rewrite /wp-admin$ $scheme://$host$uri/ permanent;

location /nginx-status {
stub_status on;
access_log off;
}
location ~ \.php$ {
fastcgi_pass unix:/var/run/php/php7.0-fpm.a.com.sock;
fastcgi_index index.php;
fastcgi_param SCRIPT_FILENAME /srv/www/a.com/public_html$fastcgi_script_name;
fastcgi_param PATH_INFO $fastcgi_script_name;
include fastcgi_params;
}
}


@LokiSharp #1