1、防火墙
yum install firewalld #安装firewalld 防火墙 systemctl start firewalld.service #开启防火墙 systemctl stop firewalld.service #关闭防火墙 systemctl enable firewalld.service #开机自动启动 systemctl disable firewalld.service #关闭开机自动启动 systemctl status firewalld #查看状态 firewall-cmd --state #查看默认防火墙状态（关闭后显示notrunning，开启后显示running） firewall-cmd --get-active-zones #获取活动的区域 firewall-cmd --get-service #获取所有支持的服务
2、网络服务
#重启网络服务 systemctl retart network.service 或 systemctl restart network #启动网络服务 systemctl start network.service 或 systemctl start network #停止网络服务 systemctl stop network.service 或 systemctl stop network #查看IP ip a
3、selinux
#查看selinux状态 sestatus #临时关闭 setenforce 0 #永久关闭,可以修改配置文件/etc/selinux/config,将其中SELINUX设置为disabled。(开启状态为 enforcing )
4、路由网关
#查看路由表 ip route
5、hostname
vi /etc/hostname #修改名字重启有效即可
6、查询系统信息
[root@ltt01 ~]# uname Linux [root@ltt01 ~]# uname -a Linux ltt01.bg.com 3.10.0-693.el7.x86_64 #1 SMP Tue Aug 22 21:09:27 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux [root@ltt01 ~]# cat /etc/redhat-release CentOS Linux release 7.4.1708 (Core)
7、用户
#添加hadoop用户 [root@node1 ~]# useradd hadoop #为hadoop用户设置密码 [root@node1 ~]# passwd hadoop #查看hadoop用户信息 [root@node1 hadoop]# id hadoop uid=1000(hadoop) gid=1000(hadoop) groups=1000(hadoop) #删除用户 -r 删除主目录和邮件池 [root@node1 ~]# userdel -rf hadoop
8、为普通用户设置sudo ，化身root进行操作
#文件只读 [root@node1 ~]# ls -l /etc/sudoers -r--r----- 1 root root 3938 May 22 15:29 /etc/sudoers #为此文件添加写权限 [root@node1 ~]# chmod -v u+w /etc/sudoers mode of ‘/etc/sudoers’ changed from 0440 (r--r-----) to 0640 (rw-r-----) [root@node1 ~]# ls -l /etc/sudoers -rw-r----- 1 root root 3938 May 22 15:29 /etc/sudoers #编辑 [root@node1 ~]# vi /etc/sudoers root ALL=(ALL) ALL hadoop ALL=(ALL) ALL #收回写权限 [root@node1 ~]# chmod -v u-w /etc/sudoers mode of ‘/etc/sudoers’ changed from 0640 (rw-r-----) to 0440 (r--r-----)
9、使用sudo
[root@node1 ~]# su hadoop [hadoop@node1 root]$ cat /etc/sudoers cat: /etc/sudoers: Permission denied [hadoop@node1 root]$ sudo cat /etc/sudoers We trust you have received the usual lecture from the local System Administrator. It usually boils down to these three things: #1) Respect the privacy of others. #2) Think before you type. #3) With great power comes great responsibility. [sudo] password for hadoop: