Let's Encrypt 安装配置教程，免费的 SSL 证书

git clone https://github.com/letsencrypt/letsencrypt

 cd letsencrypt
./certbot-auto certonly  -d *.you.cn --manual --preferred-challenges dns --server https://acme-v02.api.letsencrypt.org/directory

Dependency Installed:
  dwz.x86_64 0:0.11-3.el7             perl-srpm-macros.noarch 0:1-8.el7             tcl.x86_64 1:8.5.13-8.el7             tix.x86_64 1:8.4.3-12.el7             tk.x86_64 1:8.5.13-6.el7             tkinter.x86_64 0:2.7.5-69.el7_5            

Complete!
Creating virtual environment...
Installing Python packages...
Installation succeeded.
Saving debug log to /var/log/letsencrypt/letsencrypt.log
Plugins selected: Authenticator manual, Installer None
Enter email address (used for urgent renewal and security notices) (Enter 'c' to
cancel): 123@163.com

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Please read the Terms of Service at
https://letsencrypt.org/documents/LE-SA-v1.2-November-15-2017.pdf. You must
agree in order to register with the ACME server at
https://acme-v02.api.letsencrypt.org/directory
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(A)gree/(C)ancel: A
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Would you be willing to share your email address with the Electronic Frontier
Foundation, a founding partner of the Let's Encrypt project and the non-profit
organization that develops Certbot? We'd like to send you email about our work
encrypting the web, EFF news, campaigns, and ways to support digital freedom.
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(Y)es/(N)o: N
Obtaining a new certificate
Performing the following challenges:
dns-01 challenge for kuaichuangkeji.com

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NOTE: The IP of this machine will be publicly logged as having requested this
certificate. If you're running certbot in manual mode on a machine that is not
your server, please ensure you're okay with that.

Are you OK with your IP being logged?
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(Y)es/(N)o: Y

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Please deploy a DNS TXT record under the name
_acme-challenge.you.cn with the following value:

RYtObhDvEcXewZckknNQkBKIkvwIlbb4PNRel74LNwU

Before continuing, verify the record is deployed.
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Press Enter to Continue
Waiting for verification...
Cleaning up challenges

IMPORTANT NOTES:
 - Congratulations! Your certificate and chain have been saved at:
   /etc/letsencrypt/live/you.cn/fullchain.pem
   Your key file has been saved at:
   /etc/letsencrypt/live/you.cn/privkey.pem
   Your cert will expire on 2019-02-27. To obtain a new or tweaked
   version of this certificate in the future, simply run certbot-auto
   again. To non-interactively renew *all* of your certificates, run
   "certbot-auto renew"
 - If you like Certbot, please consider supporting our work by:

   Donating to ISRG / Let's Encrypt:   https://letsencrypt.org/donate
   Donating to EFF:                    https://eff.org/donate-le

crontab -e // 编辑定时任务
0 */12 * * * certbot renew --quiet --renew-hook "/etc/init.d/nginx reload"

/etc/letsencrypt/live/you.cn/fullchain.pem
/etc/letsencrypt/live/you.cn/privkey.pem

server {
   listen   443 ssl;
   server_name  you.cn;
   root /home/www/you;
   index  index.html index.htm index.php;

    ssl on;
    ssl_certificate /etc/letsencrypt/live/you.cn/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/you.cn/privkey.pem;
    ...
}

server {
    listen 80;
    server_name you.cn;
    location / {
        rewrite ^(.*)$  https://$host$1 permanent;
    }
}

certbot revoke --cert-path /etc/letsencrypt/live/you.cn/cert.pem
certbot delete --cert-name you.cn