添加公鑰后報錯sign_and_send_pubkey: signing failed: agent refused operation的解決辦法，或者說執行ansible playbook 時
出現的錯誤：
UNREACHABLE! => {"changed": false, "msg": "Failed to connect to the host via ssh: sign_and_send_pubkey: signing failed: agent refused operation\r\nPermission denied (publickey,gssapi-keyex,gssapi-with-mic,password).\r\n", "unreachable": true}
解決：
執行以下命令，就能解決
[root@node5 ~]# eval "$(ssh-agent -s)"
[root@node5 ~]# ssh-add