相较于传统的用户名和密码认证方式，使用 SSH 密钥有以下优势：

SSH 密钥登录认证更为安全可靠，可以杜绝暴力破解威胁。

SSH 密钥登录方式更简便，只需在控制台和本地客户端做简单配置即可远程登录实例，再次登录时无需再输入密码。

如何用SSH密钥连接你的云服务器实例？

一、生成密钥

ssh-keygen -t rsa

执行命令： ssh-keygen -t rsa

输入密钥存储路径，直接回车则为默认路径

输入密钥密码，直接回车为空密码

重复确认密码

生成成功，生成路径

进入/root/.ssh目录

touch authorized_keyscat id_rsa.pub >> authorized_keyschmod 600 authorized_keys

下载.ssh目录下的私钥id_rsa

二、配置ssh

vim /etc/ssh/sshd_config

#   $OpenBSD: sshd_config,v 1.100 2016/08/15 12:32:04 naddy Exp $# This is the sshd server system-wide configuration file.  See# sshd_config(5) for more information.# This sshd was compiled with PATH=/usr/local/bin:/usr/bin# The strategy used for options in the default sshd_config shipped with# OpenSSH is to specify options with their default value where# possible, but leave them commented.  Uncommented options override the# default value.# If you want to change the port on a SELinux system, you have to tell# SELinux about this change.# semanage port -a -t ssh_port_t -p tcp #PORTNUMBER##Port 22Port 52114#AddressFamily any#ListenAddress 0.0.0.0#ListenAddress ::HostKey /etc/ssh/ssh_host_rsa_key#HostKey /etc/ssh/ssh_host_dsa_keyHostKey /etc/ssh/ssh_host_ecdsa_keyHostKey /etc/ssh/ssh_host_ed25519_key# Ciphers and keying#RekeyLimit default none# Logging#SyslogFacility AUTHSyslogFacility AUTHPRIV#LogLevel INFO# Authentication:#LoginGraceTime 2m#PermitRootLogin yes#StrictModes yes#MaxAuthTries 6#MaxSessions 10PubkeyAuthentication yes# The default is to check both .ssh/authorized_keys and .ssh/authorized_keys2# but this is overridden so installations will only check .ssh/authorized_keysAuthorizedKeysFile  .ssh/authorized_keys#AuthorizedPrincipalsFile none#AuthorizedKeysCommand none#AuthorizedKeysCommandUser nobody# For this to work you will also need host keys in /etc/ssh/ssh_known_hosts#HostbasedAuthentication no# Change to yes if you don't trust ~/.ssh/known_hosts for# HostbasedAuthentication#IgnoreUserKnownHosts no# Don't read the user's ~/.rhosts and ~/.shosts files#IgnoreRhosts yes# To disable tunneled clear text passwords, change to no here!#PasswordAuthentication yes#PermitEmptyPasswords noPasswordAuthentication no# Change to no to disable s/key passwords#ChallengeResponseAuthentication yesChallengeResponseAuthentication no# Kerberos options#KerberosAuthentication no#KerberosOrLocalPasswd yes#KerberosTicketCleanup yes#KerberosGetAFSToken no#KerberosUseKuserok yes# GSSAPI optionsGSSAPIAuthentication yesGSSAPICleanupCredentials no#GSSAPIStrictAcceptorCheck yes#GSSAPIKeyExchange no#GSSAPIEnablek5users no# Set this to 'yes' to enable PAM authentication, account processing,# and session processing. If this is enabled, PAM authentication will# be allowed through the ChallengeResponseAuthentication and# PasswordAuthentication.  Depending on your PAM configuration,# PAM authentication via ChallengeResponseAuthentication may bypass# the setting of "PermitRootLogin without-password".# If you just want the PAM account and session checks to run without# PAM authentication, then enable this but set PasswordAuthentication# and ChallengeResponseAuthentication to 'no'.# WARNING: 'UsePAM no' is not supported in Red Hat Enterprise Linux and may cause several# problems.UsePAM yes#AllowAgentForwarding yes#AllowTcpForwarding yes#GatewayPorts noX11Forwarding yes#X11DisplayOffset 10#X11UseLocalhost yes#PermitTTY yes#PrintMotd yes#PrintLastLog yes#TCPKeepAlive yes#UseLogin no#UsePrivilegeSeparation sandbox#PermitUserEnvironment no#Compression delayed#ClientAliveInterval 0#ClientAliveCountMax 3#ShowPatchLevel no#UseDNS yes#PidFile /var/run/sshd.pid#MaxStartups 10:30:100#PermitTunnel no#ChrootDirectory none#VersionAddendum none# no default banner path#Banner none# Accept locale-related environment variablesAcceptEnv LANG LC_CTYPE LC_NUMERIC LC_TIME LC_COLLATE LC_MONETARY LC_MESSAGESAcceptEnv LC_PAPER LC_NAME LC_ADDRESS LC_TELEPHONE LC_MEASUREMENTAcceptEnv LC_IDENTIFICATION LC_ALL LANGUAGEAcceptEnv XMODIFIERS# override default of no subsystemsSubsystem   sftp    /usr/libexec/openssh/sftp-server# Example of overriding settings on a per-user basis#Match User anoncvs#   X11Forwarding no#   AllowTcpForwarding no#   PermitTTY no#   ForceCommand cvs server

配置防火墙

firewall-cmd --zone=public --add-port=52114/tcp --permanentfirewall-cmd --reload

向SELinux中添加修改的SSH端口

yum provides semanageyum -y install policycoreutils-pythonsemanage port -a -t ssh_port_t -p tcp 52114

systemctl restart sshd.service