• sshd

# 启动
systemctl restart sshd.service

# 开机自启动
systemctl enable sshd.service

• mariadb

# 启动
systemctl restart mariadb.service

# 开机自启动
systemctl enable mariadb.service

• 防火墙(最操蛋的一个)

# 关闭
systemctl stop firewalld.service

# 开机也关闭
systemctl disable firewalld.service

• 列出所有服务

systemctl list-unit-files --type=service

• 图片欣赏