连接 LDAP 服务
RH124 CHAPTER 8 CONNECTING TO NETWORK DEFINED USERS AND GROUPS
Configure LDAP Client on Ubuntu 20.04|18.04|16.04
开启 TLS 访问
Secure OpenLDAP Server with SSL/TLS on Ubuntu 20.04|18.04|16.04
证书续期（无需重启）：
Re: slapd and LetsEncrypt certificates: does a cert renewal necessitate a server restart?