10月30日任务

10.23 linux任务计划cron

10.24 chkconfig工具

10.25 systemd管理服务

10.26 unit介绍

10.27 target介绍

任务计划 crontab

在某个时间执行某些命令或脚本，做到自动化运维

cron服务配置文件

[root@localhost ~]# cat /etc/crontab
SHELL=/bin/bash
PATH=/sbin:/bin:/usr/sbin:/usr/bin
MAILTO=root# For details see man 4 crontabs# Example of job definition:
# .---------------- minute (0 - 59)
# |  .------------- hour (0 - 23)
# |  |  .---------- day of month (1 - 31)
# |  |  |  .------- month (1 - 12) OR jan,feb,mar,apr ...
# |  |  |  |  .---- day of week (0 - 6) (Sunday=0 or 7) OR sun,mon,tue,wed,thu,fri,sat
# |  |  |  |  |
# *  *  *  *  * user-name  command to be executed

常用参数

• -l 列出计划任务表

# 初始为设置，计划任务表为空
[root@localhost ~]# crontab -l
no crontab for root

• -e 编辑计划任务表

# 编辑
[root@localhost ~]# crontab -e
# 进入编辑模式，按i键后输入
0 3 * * 1-5 /usr/bin/tar -cvf /home/user1 >> user.log 2>&1按esc退出编辑模式，:wq保存退出# 查看验证
[root@localhost ~]# crontab -l
0 3 * * 1-5 /usr/bin/tar -cvf /home/user1 >> user.log 2>&1

• -u USER （可以配合其他参数使用）

[root@localhost ~]# crontab -u user1 -e[root@localhost ~]# crontab -u user1 -l
0 8 * * * echo "good morning"默认不指定-u，设置或显示的是当前用户

• -r 删除用户的计划任务表(配合-u指定用户)

[root@localhost ~]# crontab -r -u user1
[root@localhost ~]# crontab -u user1 -l
no crontab for user1

cron样例

[root@localhost ~]# man 5 crontab
...
EXAMPLE CRON FILE# use /bin/sh to run commands, no matter what /etc/passwd saysSHELL=/bin/sh# mail any output to `paul', no matter whose crontab this isMAILTO=paul#CRON_TZ=Japan# run five minutes after midnight, every day5 0 * * *       $HOME/bin/daily.job >> $HOME/tmp/out 2>&1# run at 2:15pm on the first of every month -- output mailed to paul15 14 1 * *     $HOME/bin/monthly# run at 10 pm on weekdays, annoy Joe0 22 * * 1-5    mail -s "It's 10pm" joe%Joe,%%Where are your kids?%23 0-23/2 * * * echo "run 23 minutes after midn, 2am, 4am ..., everyday"5 4 * * sun     echo "run at 5 after 4 every sunday"
...

系统服务管理chkconfig

centos6及之前版本使用

在centos7中已经不再使用chkconfig来进行系统服务的管理，改为systemctl命令了，所以只显示了部分服务

基本使用

• 显示管理的服务

[root@localhost ~]# chkconfig --list注意：该输出结果只显示 SysV 服务，并不包含原生 systemd 服务。SysV 配置数据可能被原生 systemd 配置覆盖。 如果您想列出 systemd 服务,请执行 'systemctl list-unit-files'。欲查看对特定 target 启用的服务请执行'systemctl list-dependencies [target]'。netconsole       0:关 1:关 2:关 3:关 4:关 5:关 6:关
network         0:关 1:关 2:开 3:开 4:开 5:开 6:关

• 关闭在指定运行级的上的服务

[root@localhost ~]# chkconfig --level 3 network off
[root@localhost ~]# chkconfig --list注意：该输出结果只显示 SysV 服务，并不包含原生 systemd 服务。SysV 配置数据可能被原生 systemd 配置覆盖。 如果您想列出 systemd 服务,请执行 'systemctl list-unit-files'。欲查看对特定 target 启用的服务请执行'systemctl list-dependencies [target]'。netconsole         0:关 1:关 2:关 3:关 4:关 5:关 6:关
network         0:关 1:关 2:开 3:关 4:开 5:开 6:关# 要同时关闭多个运行级的服务，如3,4,5级应该写成345(中间没有空格和逗号)
[root@localhost ~]# chkconfig --level 345  network off
[root@localhost ~]# chkconfig --list注意：该输出结果只显示 SysV 服务，并不包含原生 systemd 服务。SysV 配置数据可能被原生 systemd 配置覆盖。 如果您想列出 systemd 服务,请执行 'systemctl list-unit-files'。欲查看对特定 target 启用的服务请执行'systemctl list-dependencies [target]'。netconsole         0:关 1:关 2:关 3:关 4:关 5:关 6:关
network         0:关 1:关 2:开 3:关 4:关 5:关 6:关

• 向管理列表添加服务

# 将新服务的启动脚本加入到/etc/init.d/目录下(这里就简单拷贝下做个示范)
[root@localhost ~]# cp /etc/init.d/network /etc/init.d/ssh# 添加新服务至管理列表
[root@localhost ~]# chkconfig --add ssh
[root@localhost ~]# chkconfig --list注意：该输出结果只显示 SysV 服务，并不包含原生 systemd 服务。SysV 配置数据可能被原生 systemd 配置覆盖。 如果您想列出 systemd 服务,请执行 'systemctl list-unit-files'。欲查看对特定 target 启用的服务请执行'systemctl list-dependencies [target]'。netconsole         0:关 1:关 2:关 3:关 4:关 5:关 6:关
network         0:关 1:关 2:开 3:开 4:开 5:开 6:关
ssh             0:关 1:关 2:开 3:开 4:开 5:开 6:关

• 删除管理列表中的服务

[root@localhost etc]# chkconfig --del ssh
[root@localhost etc]# chkconfig --list注意：该输出结果只显示 SysV 服务，并不包含原生 systemd 服务。SysV 配置数据可能被原生 systemd 配置覆盖。 如果您想列出 systemd 服务,请执行 'systemctl list-unit-files'。欲查看对特定 target 启用的服务请执行'systemctl list-dependencies [target]'。netconsole       0:关 1:关 2:关 3:关 4:关 5:关 6:关
network         0:关 1:关 2:开 3:开 4:开 5:开 6:关

系统服务管理systemd(centos7)

[root@localhost ~]# systemctl list-units --all --type=serviceUNIT                      LOAD      ACTIVE   SUB     DESCRIPTIONauditd.service            loaded    active   running Security Auditing brandbot.service          loaded    inactive dead    Flexible Branding chronyd.service           loaded    active   running NTP client/servercpupower.service          loaded    inactive dead    Configure CPU powecrond.service             loaded    active   running Command Schedulerdbus.service              loaded    active   running D-Bus System Messa
● display-manager.service   not-found inactive dead    display-manager.sedracut-shutdown.service   loaded    inactive dead    Restore /run/initrebtables.service          loaded    inactive dead    Ethernet Bridge Fiemergency.service         loaded    inactive dead    Emergency Shell...systemd-vconsole-setup.service loaded    active   exited  Setup Virtualtuned.service             loaded    active   running Dynamic System Tunvmtoolsd.service          loaded    active   running Service for virtuaLOAD   = Reflects whether the unit definition was properly loaded.
ACTIVE = The high-level unit activation state, i.e. generalization of SUB
SUB    = The low-level unit activation state, values depend on unit type.83 loaded units listed.
To show all installed unit files use 'systemctl list-unit-files'.
lines 76-91/91 (END)# 不加--all，只列出active状态的服务
[root@localhost ~]# systemctl list-units --type=serviceUNIT                      LOAD   ACTIVE SUB     DESCRIPTIONauditd.service            loaded active running Security Auditing Servichronyd.service           loaded active running NTP client/servercrond.service             loaded active running Command Schedulerdbus.service              loaded active running D-Bus System Message Bufirewalld.service         loaded active running firewalld - dynamic firgetty@tty1.service        loaded active running Getty on tty1
...

• 设置服务开机启动/不启动

# 开机启动，服务后可加可不加.service，系统会创建服务脚本文件的软链接
[root@localhost ~]# systemctl enable crond
[root@localhost ~]# systemctl enable crond.service
Created symlink from /etc/systemd/system/multi-user.target.wants/crond.service to /usr/lib/systemd/system/crond.service.# crond.service脚本内容如下
[root@localhost ~]# cat /usr/lib/systemd/system/crond.service
[Unit]
Description=Command Scheduler
After=auditd.service systemd-user-sessions.service time-sync.target[Service]
EnvironmentFile=/etc/sysconfig/crond
ExecStart=/usr/sbin/crond -n $CRONDARGS
ExecReload=/bin/kill -HUP $MAINPID
KillMode=process[Install]
WantedBy=multi-user.target# 设置开机不启动，系统移除服务脚本的软链接
[root@localhost ~]# systemctl disable crond
Removed symlink /etc/systemd/system/multi-user.target.wants/crond.service.

• 查看服务状态

[root@localhost ~]# systemctl status crond
● crond.service - Command SchedulerLoaded: loaded (/usr/lib/systemd/system/crond.service; enabled; vendor preset: enabled)Active: active (running) since 四 2017-10-26 17:51:07 CST; 2h 28min agoMain PID: 525 (crond)CGroup: /system.slice/crond.service└─525 /usr/sbin/crond -n10月 26 17:51:07 localhost.localdomain systemd[1]: Started Command Sc...
10月 26 17:51:07 localhost.localdomain systemd[1]: Starting Command S...
10月 26 17:51:08 localhost.localdomain crond[525]: (CRON) INFO (RANDO...
10月 26 17:51:10 localhost.localdomain crond[525]: (CRON) INFO (runni...
Hint: Some lines were ellipsized, use -l to show in full.

• 停止服务

[root@localhost ~]# systemctl stop crond

• 启动服务

[root@localhost ~]# systemctl start crond

• 重启服务

[root@localhost ~]# systemctl restart crond

• 检查服务是否开机启动

[root@localhost ~]# systemctl is-enabled crond
enabled

unit介绍

列出系统内所有unit

[root@localhost ~]# ls /usr/lib/systemd/system
arp-ethers.service
auditd.service
autovt@.service
basic.target
basic.target.wants
blk-availability.service
bluetooth.target
brandbot.path
brandbot.service
chrony-dnssrv@.service
chrony-dnssrv@.timer
chronyd.service
chrony-wait.service
...

unit分为以下类型 类型 | 说明 | 举例 --- | --- | --- service | 系统服务 | crond.service target | 多个unit组成的组 | timers.target device | 硬件设备 | mount | 文件系统挂载点 | dev-mqueue.mount automount | 自动挂载点 | path | 文件或路径 | systemd-ask-password-console.path scope | 不是由systemd启动的外部进程 | slice | 进程组 | system.slice snapshot | systemd快照 | socket | 进程间通信套接字 | systemd-shutdownd.socket swap | swap文件 | timer | 定时器 | systemd-readahead-done.timer

unit相关命令

• 只显示active状态的unit；加上--all参数全部显示

[root@localhost system]# systemctl list-unitsUNIT                      LOAD   ACTIVE SUB       DESCRIPTIONproc-sys-fs-binfmt_misc.automount loaded active waiting   Arbitrary Exesys-devices-pci0000:00-0000:00:07.1-ata2-host2-target2:0:0-2:0:0:0-blocsys-devices-pci0000:00-0000:00:10.0-host0-target0:0:0-0:0:0:0-block-sdasys-devices-pci0000:00-0000:00:10.0-host0-target0:0:0-0:0:0:0-block-sdasys-devices-pci0000:00-0000:00:10.0-host0-target0:0:0-0:0:0:0-block-sdasys-devices-pci0000:00-0000:00:10.0-host0-target0:0:0-0:0:0:0-block-sdasys-devices-pci0000:00-0000:00:10.0-host0-target0:0:1-0:0:1:0-block-sdbsys-devices-pci0000:00-0000:00:11.0-0000:02:01.0-net-ens33.device loadesys-devices-pci0000:00-0000:00:11.0-0000:02:02.0-sound-card0.device loasys-devices-platform-serial8250-tty-ttyS1.device loaded active plugged sys-devices-platform-serial8250-tty-ttyS2.device loaded active plugged sys-devices-platform-serial8250-tty-ttyS3.device loaded active plugged sys-devices-pnp0-00:05-tty-ttyS0.device loaded active plugged   /sys/desys-module-configfs.device loaded active plugged   /sys/module/configfssys-subsystem-net-devices-ens33.device loaded active plugged   82545EM
lines 1-16

• 只显示状态为inactive的unit（配合--type=service再次只刷选出服务）

[root@localhost system]# systemctl list-units --all --state=inactiveUNIT                      LOAD      ACTIVE   SUB  DESCRIPTIONproc-sys-fs-binfmt_misc.mount loaded    inactive dead Arbitrary Executasys-fs-fuse-connections.mount loaded    inactive dead FUSE Control Filetmp.mount                 loaded    inactive dead Temporary Directorysystemd-ask-password-console.path loaded    inactive dead Dispatch Passbrandbot.service          loaded    inactive dead Flexible Branding Sercpupower.service          loaded    inactive dead Configure CPU power r
● display-manager.service   not-found inactive dead display-manager.servidracut-shutdown.service   loaded    inactive dead Restore /run/initramfebtables.service          loaded    inactive dead Ethernet Bridge Filteemergency.service         loaded    inactive dead Emergency Shell
● exim.service              not-found inactive dead exim.service

• 只显示状态为active的服务

[root@localhost system]# systemctl list-units --type=serviceUNIT                      LOAD   ACTIVE SUB     DESCRIPTIONauditd.service            loaded active running Security Auditing Servichronyd.service           loaded active running NTP client/servercrond.service             loaded active running Command Schedulerdbus.service              loaded active running D-Bus System Message Bufirewalld.service         loaded active running firewalld - dynamic firgetty@tty1.service        loaded active running Getty on tty1
● kdump.service             loaded failed failed  Crash recovery kernel akmod-static-nodes.service loaded active exited  Create list of requirednetwork.service           loaded active exited  LSB: Bring up/down netwNetworkManager-wait-online.service loaded active exited  Network ManageNetworkManager.service    loaded active running Network Managerpolkit.service            loaded active running Authorization Managerpostfix.service           loaded active running Postfix Mail Transport rhel-dmesg.service        loaded active exited  Dump dmesg to /var/log/rhel-import-state.service loaded active exited  Import network configur
lines 1-16[root@localhost system]# systemctl list-units --state=active

• 查看服务是否启动

[root@localhost system]# systemctl is-active crond.service
active

target介绍

为了方便管理用target来管理unit，一个target是多个unit的组合

• 列出系统内所有的target

[root@localhost system]# systemctl list-unit-files --type=target
UNIT FILE                 STATE
basic.target              static
bluetooth.target          static
cryptsetup-pre.target     static
cryptsetup.target         static
ctrl-alt-del.target       disabled
default.target            enabled
emergency.target          static
final.target              static
getty.target              static
graphical.target          static
halt.target               disabled
hibernate.target          static
hybrid-sleep.target       static
initrd-fs.target          static
...

• 查看指定target下面的units组成

target下还可以有target

[root@localhost system]# systemctl list-dependencies multi-user.target
multi-user.target
● ├─auditd.service
● ├─brandbot.path
● ├─chronyd.service
● ├─crond.service
● ├─dbus.service
● ├─irqbalance.service
● ├─kdump.service
● ├─network.service
● ├─NetworkManager.service
● ├─plymouth-quit-wait.service
● ├─plymouth-quit.service
...

• 查看系统默认的target

[root@localhost system]# systemctl get-default
multi-user.targe

• 设置系统默认的target（类似于centos6内的修改系统运行级别）

[root@localhost system]# systemctl set-default multi-user.target
Removed symlink /etc/systemd/system/default.target.
Created symlink from /etc/systemd/system/default.target to /usr/lib/systemd/system/multi-user.target.

在CentOS6中在 /etc/inittab 文件中可以修改系统的运行级别，而在CentOS7中使用了类似的target来管理运行级

# /usr/lib/systemd/system目录下
[root@localhost system]# ls -l runlevel*.target
lrwxrwxrwx. 1 root root 15 10月 18 02:32 runlevel0.target -> poweroff.target
lrwxrwxrwx. 1 root root 13 10月 18 02:32 runlevel1.target -> rescue.target
lrwxrwxrwx. 1 root root 17 10月 18 02:32 runlevel2.target -> multi-user.target
lrwxrwxrwx. 1 root root 17 10月 18 02:32 runlevel3.target -> multi-user.target
lrwxrwxrwx. 1 root root 17 10月 18 02:32 runlevel4.target -> multi-user.target
lrwxrwxrwx. 1 root root 16 10月 18 02:32 runlevel5.target -> graphical.target
lrwxrwxrwx. 1 root root 13 10月 18 02:32 runlevel6.target -> reboot.target

小结

• 一个service属于一种类型的unit
• 同类型的多个unit组成一个target
• 一个target内包含多个service

查看service属于哪个target(看Install块)

[root@localhost system]# cat /usr/lib/systemd/system/sshd.service
[Unit]
Description=OpenSSH server daemon
Documentation=man:sshd(8) man:sshd_config(5)
After=network.target sshd-keygen.service
Wants=sshd-keygen.service[Service]
Type=forking
PIDFile=/var/run/sshd.pid
EnvironmentFile=/etc/sysconfig/sshd
ExecStart=/usr/sbin/sshd $OPTIONS
ExecReload=/bin/kill -HUP $MAINPID
KillMode=process
Restart=on-failure
RestartSec=42s[Install]
WantedBy=multi-user.target