現象：systemctl start httpd 啟動超時，提示資訊如下：
Job for httpd.service failed because the control process exited with error code. See "systemctl status httpd.service" and "journalctl -xe" for details.
systemctl status httpd資訊如下：
httpd.service: start operation timed out. Terminating. httpd.service: Failed with result 'timeout'.
相關日誌中沒有報錯；如/var/log/httpd/error_log、/var/log/message
網上搜尋到的解決方法：
1. 加長服務啟動超時時間（未解決）
新增下述檔案： # /usr/lib/systemd/system/httpd.service.d/timeout.conf [Service] TimeoutStartSec=600 # systemctl daemon-reload # sysetmctl show httpd # journalctl -u httpd # systemctl restart httpd
參考連結：
https://askubuntu.com/questions/1309084/how-do-i-avoid-timeouts-and-get-apache2-to-start-at-system-startup#
2.修改service啟動命令（未解決）
# /usr/lib/systemd/system/httpd.service ExecStart=/usr/sbin/httpd $OPTIONS -DFOREGROUND 改為 ExecStart=/bin/bash -c "/usr/sbin/httpd $OPTIONS -DFOREGROUND"
3.修改service環境變數（未解決）
# /usr/lib/systemd/system/httpd.service Environment=LANG=C 改為 Environment=APACHE_STARTED_BY_SYSTEMD=true
4.註釋service Type（解決）
# /usr/lib/systemd/system/httpd.service 將下述內容註釋 Type=notify
# systemctl dameon-reload
原因：notify需載入mod_systemd 模組
新建檔案用以載入所需模組 # vim /etc/httpd/conf.modules.d/systemc.conf LoadModule systemd_module modules/mod_systemd.so 將service Type註釋取消
# systemctl daemon-reload
# systemctl restart httpd