快速配置Let's encrypt通配符证书

本文首发链接
查看我的个人博客：https://hubinqiang.com

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利用certbot工具配置Let’s encrypt通配符证书，所域名下所有的子域名都能方便的使用 https证书，而且完全免费。值得关注的是，Let’s encrypt通配符证书只是针对二级域名，并不能针对主域名，如*.hubinqiang.com和hubinqiang.com 被认为是两个域名，如果和我一样使用的是主域名，在申请的时候需要注意都要申请。

配置环境

操作系统：Ubuntu16.04 LTS
配置域名：hubinqiang.com，*.hubinqiang.com

步骤

1. 获取Certbot

# 下载
wget https://dl.eff.org/certbot-auto
# 设为可执行权限
chmod u+x certbot-auto

2. 申请证书

执行

./certbot-auto certonly  -d "*.hubinqiang.com" -d "hubinqiang.com" --manual --preferred-challenges dns-01  --server https://acme-v02.api.letsencrypt.org/directory

参数说明：

• -certonly，表示安装模式，Certbot 有安装模式和验证模式两种类型的插件。
• -manual，表示手动安装插件，Certbot 有很多插件，不同的插件都可以申请证书，用户可以根据需要自行选择。
• -d，为哪些主机申请证书，如果是通配符，输入 *.hubinqiang.com（替换为自己的域名）。
• -preferred-challenges，使用 DNS 方式校验域名所有权。
• -server，Let’s Encrypt ACME v2 版本使用的服务器不同于 v1 版本，需要显示指定。

注意：将hubinqiang.com替换为自己的域名。可以通过多个-d 参数添加多个主机。

申请过程中需要如下确认：

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): hubinqiang@126.com

-------------------------------------------------------------------------------
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
-------------------------------------------------------------------------------
(A)gree/(C)ancel: A

-------------------------------------------------------------------------------
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 EFF and
our work to encrypt the web, protect its users and defend digital rights.
-------------------------------------------------------------------------------
(Y)es/(N)o: Y
Obtaining a new certificate
Performing the following challenges:
dns-01 challenge for hubinqiang.com
dns-01 challenge for hubinqiang.com

-------------------------------------------------------------------------------
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?
-------------------------------------------------------------------------------
(Y)es/(N)o: Y

-------------------------------------------------------------------------------

在域名 DNS 解析中添加 TXT记录：

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

kC-QHSWO1LdIeyIs7VQ66sTAyioISnfzIJU0bXgo-Z8

Before continuing, verify the record is deployed.
-------------------------------------------------------------------------------
Press Enter to Continue

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

6XnGyee8W48QfRl61m_18aRs8rfvn4T8kKzQil0IYw4

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

显示我两个主机的 TXT 记录有两条，根据要求分别在 DNS 解析中添加两条 TXT 记录，其中一条如下：

注意：若申请了多个主机，需要添加多个 TXT 记录。要求给 _acme-challenge.hubinqiang.com 配置 TXT 记录，在没有确认 TXT 记录生效之前不要回车执行。

确认生效后会有如下提示：

IMPORTANT NOTES:
 - Congratulations! Your certificate and chain have been saved at:
   /etc/letsencrypt/live/hubinqiang.com/fullchain.pem
   Your key file has been saved at:
   /etc/letsencrypt/live/hubinqiang.com/privkey.pem
   Your cert will expire on 2018-08-12. 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"
 - Your account credentials have been saved in your Certbot
   configuration directory at /etc/letsencrypt. You should make a
   secure backup of this folder now. This configuration directory will
   also contain certificates and private keys obtained by Certbot so
   making regular backups of this folder is ideal.
 - 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

进入/etc/letsencrypt/live/hubinqiang.com/中可以看到几个文件，cert.pem、chain.pem、fullchain.pem、privkey.pem，说明已经成功获取证书和密钥。

3. 配置证书

在 nginx 中配置的片段：

server {
    server_name hubinqiang.com;
    listen 443 http2 ssl;
    ssl on;
    ssl_certificate /etc/letsencrypt/live/hubinqiang.com/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/hubinqiang.com/privkey.pem;
    ssl_trusted_certificate  /etc/letsencrypt/live/hubinqiang.com/chain.pem;

重启 nginx 查看效果。

4. 证书更新

Let’s encrypt 的免费证书默认有效期为 90 天，到期后如果要续期可以执行：

certbot-auto renew