==install letencrypt
yum install certbot python2-certbot-nginx
firewall-cmd --permanent --zone=public --add-service=https
firewall-cmd --reload
===Obtaining a certificate for dev.packetlove.com
certbot --nginx -d dev.packetlove.com
===Renewing a certificate
certbot renew --dry-run
certbot renew
nginx -s reload
===vi /etc/cron.daily/letsencrypt-renew
#!/bin/sh
if certbot renew > /var/log/letsencrypt/renew.log 2>&1 ; then
nginx -s reload
fi
exit
===chown
chmod +x /etc/cron.daily/letsencrypt-renew
===crontab -e
01 02,14 * * * /etc/cron.daily/letsencrypt-renew
===analyse ssl
https://www.ssllabs.com/ssltest/analyze.html?d=dev.packetlove.com