服务控制和网络管理
目录
服务控制方式
//语法：systemctl COMMAND name[.service｜.target]
//常用COMMAND：
start name.service //启动服务
stop name.service //停止服务
restart name.service //重启服务
status name.service //查看服务状态
try-restart name.service //条件式重启服务，若服务已经启动则重启，若服务未启动则不做任何操作
reload-or-restart name.service //重载或重启服务，能reload则reload，否则restart
reload-or-try-restart name.service //重载或条件式重启服务，能reload则reload，否则try-restart
mask name.service //禁止设定为开机自启
unmask name.service //取消禁止设定为开机自启
list-dependencies name.service //查看服务的依赖关系
is-active name.service //查看某服务当前激活与否的状态
is-enabled name.service //查看服务是否开机自动启动
enable name.service //设定某服务开机自动启动
disable name.service //禁止服务开机自动启动
isolate name.target //切换至某级别，如systemctl isolate graphical.target就是切换至图形界面
list-unit-files --type service //查看所有服务的开机自动启动状态（是否开机自启）
list-units --type service //查看所有已经激活的服务状态信息
list-units --type target //查看所有已装载的级别
list-units --type service --all //查看所有服务（已启动/已停止）的状态信息
list-units --type target --all //查看所有的级别
get-default //查看默认运行级别
set-default name.target //设置默认运行级别
rescue //切换至紧急救援模式（大多数服务不启动，但是会加载驱动）
emergency //切换至emergency模式（驱动不会加载，系统不会初始化，服务不会启动）
halt //关机
poweroff //关机
reboot //重启
suspend //挂起系统，此时不能关机，否则无用
hibernate //创建并保存系统快照，下次系统重启时会自动载入快照
hybrid-sleep //混合睡眠，快照并挂起
启动服务
[root@YL ~]# systemctl start firewalld
停止服务
[root@YL ~]# systemctl stop firewalld
重启服务
[root@YL ~]# systemctl restart firewalld
查看服务状态
[root@YL ~]# systemctl status firewalld
● firewalld.service - firewalld - dynamic firewall daemon
Loaded: loaded (/usr/lib/systemd/system/firewalld.service; ena>
Active: active (running) since Wed 2022-07-13 23:02:43 CST; 6s>
Docs: man:firewalld(1)
Main PID: 52620 (firewalld)
设定某服务开机自动启动
[root@YL ~]# systemctl enable firewalld
Created symlink /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service → /usr/lib/systemd/system/firewalld.service.
Created symlink /etc/systemd/system/multi-user.target.wants/firewalld.service → /usr/lib/systemd/system/firewalld.service.
禁止服务开机自动启动
[root@YL ~]# systemctl disable firewalld
Removed /etc/systemd/system/multi-user.target.wants/firewalld.service.
Removed /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service.
查看某服务当前激活与否的状态
[root@YL ~]# systemctl is-active firewalld
active
查看服务是否开机自动启动
[root@YL ~]# systemctl is-enabled firewalld
disabled
查看默认运行级别
[root@YL ~]# systemctl get-default
multi-user.target
把httpd服务加入system中
[Unit]
Description=httpd server daemon
After=network.target sshd-keygen.target
[Service]
Type=forking
ExecStart=/usr/local/httpd/bin/httpd
ExecStop=/usr/local/httpd/bin/httpd -s stop
ExecReload=/bin/kill -HUP $MAINPID
[Install]
WantedBy=multi-user.target
让其生效查看是否添加成功
[root@YL system]# systemctl daemon-reload
[root@YL system]# systemctl status httpd.service
● httpd.service - httpd server daemon
Loaded: loaded (/usr/lib/systemd/system/httpd.service; disable>
Active: inactive (dead)
lines 1-3/3 (END)
将httpd服务设置为开机自启
[root@YL system]# systemctl enable --now httpd
Created symlink /etc/systemd/system/multi-user.target.wants/httpd.service → /usr/lib/systemd/system/httpd.service
[root@YL system]#
[root@YL system]# systemctl status httpd.service
● httpd.service - httpd server daemon
Loaded: loaded (/usr/lib/systemd/system/httpd.service; enable>
Active: active (running) since Thu 2022-07-14 09:07:18 CST; 7>
Process: 1774 ExecStart=/usr/local/httpd/bin/httpd (code=exite>
Main PID: 1775 (httpd)
修改网卡配置文件
[root@YL ~]# cd /etc/sysconfig/network-scripts/
[root@YL network-scripts]# mv ifcfg-ens160 ifcfg-eth0
[root@YL network-scripts]# vim ifcfg-eth0
TYPE=Ethernet
BOOTPROTO=dhcp
DEFROUTE=yes
NAME=eth0
DEVICE=eth0
ONBOOT=yes
编辑/etc/default/grub配置文件，在以GRUB_CMDLINE_LINUX开头的行内rhgb的前面加上net.ifnames=0 biosdevname=0
[root@YL network-scripts]# cat /etc/default/grub |tail -3
GRUB_CMDLINE_LINUX="crashkernel=auto resume=/dev/mapper/cs-swap rd.lvm.lv=cs/root rd.lvm.lv=cs/swap net.ifnames=0 biosdevname=0 rhgb quiet"
GRUB_DISABLE_RECOVERY="true"
GRUB_ENABLE_BLSCFG=true
为grub2生成其配置文件
[root@YL network-scripts]# grub2-mkconfig -o /etc/grub2.cfg
Generating grub configuration file ...
done
ifconfig
网卡配置信息含义如下:
UP: 网卡处于活动状态
BROADCAST: 支持广播
RUNNING: 网线已接入
MULTICAST: 支持组播
MTU: 最大传输单元(字节),即此接口一次所能传输的最大封包
inet: 显示IPv4地址行
inet6: 显示IPv6地址行
link/enther: 指设备硬件(MAC)地址
txqueuelen: 传输缓存区长度大小
RX packets: 接收的数据包
TX packets: 发送的数据包
errors: 总的收包的错误数量
dropped: 由于各种原因, 导致拷贝在内存过程中被丢弃
collisions: 网络信号冲突情况, 值不为0则可能存在网络故障
[root@YL ~]# ifconfig
ens160: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.124.128 netmask 255.255.255.0 broadcast 192.168.124.255
inet6 fe80::9fb7:6eb1:f172:7121 prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:18:57:bd txqueuelen 1000 (Ethernet)
RX packets 5203 bytes 418833 (409.0 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 2874 bytes 323698 (316.1 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10<
查看当前处于活动状态的所有网络接口
[root@YL ~]# ifconfig eth0
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.124.128 netmask 255.255.255.0 broadcast 192.168.124.255
inet6 fe80::20c:29ff:fe18:57bd prefixlen 64 scopeid 0x20<link>
查看所有网卡状态信息, 包括禁用和启用
[root@YL ~]# ifconfig -a
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.124.128 netmask 255.255.255.0 broadcast 192.168.124.255
inet6 fe80::20c:29ff:fe18:57bd prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:18:57:bd txqueuelen 1000 (Ethernet)
RX packets 119 bytes 11848 (11.5 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 81 bytes 10487 (10.2 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10<
查看网络接口所有地址
[root@YL ~]# ip link show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP mode DEFAULT group default qlen 1000
link/ether 00:0c:29:18:57:bd brd ff:ff:ff:ff:ff:ff
显示报文统计信息
[root@YL ~]# ip -s link show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
RX: bytes packets errors dropped overrun mcast
0 0 0 0 0 0
TX: bytes packets errors dropped carrier collsns
0 0 0 0 0 0
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP mode DEFAULT group default qlen 1000
启用或禁用网络接口
[root@YL ~]# ip link set lo up
[root@YL ~]# ip link set eth0 up
添加ip地址
[root@YL ~]# ip addr add 192.168.255.200/24 dev eth0
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
link/ether 00:0c:29:18:57:bd brd ff:ff:ff:ff:ff:ff
inet 192.168.124.128/24 brd 192.168.124.255 scope global dynamic noprefixroute eth0
valid_lft 1631sec preferred_lft 1631sec
inet 192.168.255.200/24 scope global eth0
删除ip地址
[root@YL ~]# ip addr del 192.168.255.200/24 dev eth0
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
link/ether 00:0c:29:18:57:bd brd ff:ff:ff:ff:ff:ff
inet 192.168.124.128/24 brd 192.168.124.255 scope global dynamic noprefixroute eth0
valid_lft 1545sec preferred_lft 1545sec
inet6 fe80::20c:29ff:fe18:57bd/64 scope link
valid_lft forever preferred_lft forever
查看网络接口的地址
[root@YL ~]# ip addr show eth0
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
link/ether 00:0c:29:18:57:bd brd ff:ff:ff:ff:ff:ff
inet 192.168.124.128/24 brd 192.168.124.255 scope global dynamic noprefixroute eth0
valid_lft 1413sec preferred_lft 1413sec
inet6 fe80::20c:29ff:fe18:57bd/64 scope link
valid_lft forever preferred_lft forever
查看当前路由表
[root@YL ~]# route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
default _gateway 0.0.0.0 UG 100 0 0 eth0
192.168.124.0 0.0.0.0 255.255.255.0 U 100 0 0 eth0
以数字方式显示各主机或端口等相关信息
[root@YL ~]# route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 192.168.124.2 0.0.0.0 UG 100 0 0 eth0
192.168.124.0 0.0.0.0 255.255.255.0 U 100 0 0 eth0
查看主机名
[root@YL ~]# hostname
YL
查看主机信息
[root@YL ~]# hostnamectl
Static hostname: YL
Icon name: computer-vm
Chassis: vm
Machine ID: a5498e9a6f114267ab30dfad1e261e55
Boot ID: e9f2d7f03c9d46daa78062eb6bee2f33
Virtualization: vmware
Operating System: CentOS Stream 8
CPE OS Name: cpe:/o:centos:centos:8
Kernel: Linux 4.18.0-257.el8.x86_64
Architecture: x86-64
