10.23 linux任务计划cron
linux任务计划配置文件
[root@hyc-01-01 ~]# cat /etc/crontab
SHELL=/bin/bash 文件中定义的shell
PATH=/sbin:/bin:/usr/sbin:/usr/bin 定义的环境变量（命令的路径）
MAILTO=root 给哪个用户发送邮件
# For details see man 4 crontabs
以下是任务计划的格式
# Example of job definition:
# .---------------- minute (0 - 59) 时间的分钟
# | .------------- hour (0 - 23) 时间的小时
# | | .---------- day of month (1 - 31) 一个月中的日期
# | | | .------- month (1 - 12) OR jan,feb,mar,apr ... 某个月（可以写数字或英文简写）
# | | | | .---- day of week (0 - 6) (Sunday=0 or 7) OR sun,mon,tue,wed,thu,fri,sat 星期几（0或7均表示周日）
# | | | | |
# * * * * * user-name command to be executed 用户 要执行的命令
定义一个任务计划
[root@hyc-01-01 ~]# crontab –e 用法同vim
no crontab for root - using an empty one
0 3 * * * /bin/bash /usr/local/sbin/123.sh>>/tmp/123.log 2>>/tmp/123.log
解释：在每月每周每日的3点执行shell脚本123.sh，将执行结果中正确的内容追加重定向到123.log文件，将执行结果中错误的内容也追加重定向到123.log文件
[root@hyc-01-01 ~]# crontab –e
no crontab for root - using an empty one
0 3 1-10 */2 2,5 /bin/bash /usr/local/sbin/123.sh>>/tmp/123.log 2>>/tmp/123.log
解释：在偶数月的1到10号的周二和周五的凌晨3点执行shell脚本
如何指定年份执行脚本？
每年的同一个日期的星期一定是不一样的，可以基于此确定脚本执行的年份
启动任务计划cron
[root@hyc-01-01 ~]# ps aux|grep cron
root 503 0.0 0.1 126264 1696 ? Ss 03:48 0:00 /usr/sbin/crond -n
root 6833 0.0 0.0 112676 984 pts/0 S+ 20:45 0:00 grep --color=auto cron
有上面的进程则说明服务已经启动
[root@hyc-01-01 ~]# systemctl status crond
● crond.service - Command Scheduler
Loaded: loaded (/usr/lib/systemd/system/crond.service; enabled; vendor preset: enabled)
Active: active (running) since 日 2018-07-15 22:05:31 CST; 1 day 22h ago
Main PID: 503 (crond)
CGroup: /system.slice/crond.service
└─503 /usr/sbin/crond -n
7月 15 22:05:31 hyc-01-01 systemd[1]: Started Command Scheduler.
7月 15 22:05:31 hyc-01-01 systemd[1]: Starting Command Scheduler...
7月 15 22:05:31 hyc-01-01 crond[503]: (CRON) INFO (RANDOM_DELAY will be scaled....)
7月 15 22:05:32 hyc-01-01 crond[503]: (CRON) INFO (running with inotify support)
Hint: Some lines were ellipsized, use -l to show in full.
以上active为active（running）且为绿色说明服务正常启动
[root@hyc-01-01 ~]# systemctl stop crond
[root@hyc-01-01 ~]# systemctl status crond
● crond.service - Command Scheduler
Loaded: loaded (/usr/lib/systemd/system/crond.service; enabled; vendor preset: enabled)
Active: inactive (dead) since 二 2018-07-17 20:50:11 CST; 2s ago
Main PID: 503 (code=exited, status=0/SUCCESS)
7月 15 22:05:31 hyc-01-01 systemd[1]: Started Command Scheduler.
7月 15 22:05:31 hyc-01-01 systemd[1]: Starting Command Scheduler...
7月 15 22:05:31 hyc-01-01 crond[503]: (CRON) INFO (RANDOM_DELAY will be scaled....)
7月 15 22:05:32 hyc-01-01 crond[503]: (CRON) INFO (running with inotify support)
7月 17 20:50:11 hyc-01-01 systemd[1]: Stopping Command Scheduler...
7月 17 20:50:11 hyc-01-01 systemd[1]: Stopped Command Scheduler.
Hint: Some lines were ellipsized, use -l to show in full.
此时crond服务未启动
crond任务计划中的脚本未执行的原因
有时脚本中用到的命令不在crond配置文件（/etc/crontab）定义的PATH路径中，导致找不到命令无法执行：
解决办法：
1 在配置文件的PATH路径中加入对应命令的路径
2 写任务计划时直接写命令的绝对路径
建议写任务计划时将执行的正确和错误结果重定向到文件，这样使执行过程有据可查，可以清楚的知道任务是否正确执行
-l 查看系统当前用户的任务计划
[root@hyc-01-01 ~]# crontab -l
0 3 * * * /bin/bash /usr/local/sbin/123.sh>>/tmp/123.log 2>>/tmp/123.log
crontab文件
[root@hyc-01-01 ~]# cat /var/spool/cron/root
0 3 * * * /bin/bash /usr/local/sbin/123.sh>>/tmp/123.log 2>>/tmp/123.log
该文件存放crontab –l命令显示的内容
10.24 chkconfig工具
chkconfig工具在centos6及更早的版本中常用，centos7不常用
查看当前系统中使用chkconfig工具的服务
[root@hyc-01-01 ~]# chkconfig --list
注：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。
要列出 systemd 服务，请执行 'systemctl list-unit-files'。
查看在具体 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
centos6及更早版本使用的服务管理机制叫SysV，centos7使用的服务管理机制为systemd；
centos7中的服务管理进程为systemd，centos6的服务管理进程为init；
[root@hyc-01-01 ~]# ls /etc/init.d 以上两个服务脚本的存放位置
functions netconsole network README
关闭network服务
[root@hyc-01-01 ~]# chkconfig network off
[root@hyc-01-01 ~]# chkconfig --list
注：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。
要列出 systemd 服务，请执行 'systemctl list-unit-files'。
查看在具体 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:关 3:关 4:关 5:关 6:关
以上0-6的开关表示在0-6的7个级别分别是什么状态，数字对应的开关表示开机启动或关闭
几个级别的状态：
0 关机状态
1 单用户模式
2 比3级别少了NFS服务
3 无图形化界面的多用户模式
4 保留级别
5 多用户带图形
6 重启
centos6及更早的版本通过修改/etc/inittab定义服务的运行级别，centos7中已不再使用
指定某一级别时关闭或开启服务
[root@hyc-01-01 ~]# chkconfig --level 3 network on
[root@hyc-01-01 ~]# chkconfig --list
注：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。
要列出 systemd 服务，请执行 'systemctl list-unit-files'。
查看在具体 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:关 3:开 4:关 5:关 6:关
[root@hyc-01-01 ~]# chkconfig --level 234 network on
[root@hyc-01-01 ~]# chkconfig --list
注：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。
要列出 systemd 服务，请执行 'systemctl list-unit-files'。
查看在具体 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:关 6:关
一般0/1/6级别服务关闭，其他级别服务可以选择性开启
将某个服务/脚本加入chkconfig列表
[root@hyc-01-01 init.d]# cp network 123 123作为新的脚本/服务
[root@hyc-01-01 init.d]# ls
123 functions netconsole network README
[root@hyc-01-01 init.d]# chkconfig --add 123 将123加入chkconfig服务列表
[root@hyc-01-01 init.d]# chkconfig --list
注：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。
要列出 systemd 服务，请执行 'systemctl list-unit-files'。
查看在具体 target 启用的服务请执行
'systemctl list-dependencies [target]'。
123 0:关 1:关 2:开 3:开 4:开 5:开 6:关
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:关 6:关
加入服务列表的要求：
1 将指定的脚本放到/etc/init.d目录下
2 文件名称无要求
3 文件内容为shell脚本
4 文件中必须有红字内容才能被识别
#! /bin/bash
#
# network Bring up/down networking
#
# chkconfig: 2345 10 90
# description: Activates/Deactivates all network interfaces configured to \
# start at boot time.
#
### BEGIN INIT INFO
…
从列表中删除某服务
[root@hyc-01-01 init.d]# chkconfig --del 123
[root@hyc-01-01 init.d]# chkconfig --list
注：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。
要列出 systemd 服务，请执行 'systemctl list-unit-files'。
查看在具体 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:关 6:关
10.25 systemd管理服务
systemd是centos7的服务管理机制
列出systemd中的service
[root@hyc-01-01 ~]# systemctl list-units --all --type=service
UNIT LOAD ACTIVE SUB DESCRIPTION
auditd.service loaded active running Security Auditing Service
brandbot.service loaded inactive dead Flexible Branding Service
chronyd.service loaded active running NTP client/server
cpupower.service loaded inactive dead Configure CPU power relate
crond.service loaded active running Command Scheduler
dbus.service loaded active running D-Bus System Message Bus
● display-manager.service not-found inactive dead display-manager.service
dracut-shutdown.service loaded inactive dead Restore /run/initramfs
ebtables.service loaded inactive dead Ethernet Bridge Filtering
emergency.service loaded inactive dead Emergency Shell
● exim.service not-found inactive dead exim.service
firewalld.service loaded active running firewalld - dynamic firewa
getty@tty1.service loaded active running Getty on tty1
ip6tables.service loaded inactive dead IPv6 firewall with ip6tabl
● ipset.service not-found inactive dead ipset.service
iptables.service loaded inactive dead IPv4 firewall with iptable
irqbalance.service loaded inactive dead irqbalance daemon
● kdump.service loaded failed failed Crash recovery kernel armi
kmod-static-nodes.service loaded active exited Create list of required st
microcode.service loaded inactive dead Load CPU microcode update
network.service loaded active exited LSB: Bring up/down network
NetworkManager-wait-online.service loaded active exited Network Manager Wait
NetworkManager.service loaded active running Network Manager
● ntpd.service not-found inactive dead ntpd.service
● ntpdate.service not-found inactive dead ntpdate.service
plymouth-quit-wait.service loaded inactive dead Wait for Plymouth Boot Scr
plymouth-quit.service loaded inactive dead Terminate Plymouth Boot Sc
plymouth-read-write.service loaded inactive dead Tell Plymouth To Write Out
plymouth-start.service loaded inactive dead Show Plymouth Boot Screen
polkit.service loaded active running Authorization Manager
postfix.service loaded active running Postfix Mail Transport Age
rc-local.service loaded inactive dead /etc/rc.d/rc.local Compati
rescue.service loaded inactive dead Rescue Shell
rhel-autorelabel-mark.service loaded inactive dead Mark the need to relabel
rhel-autorelabel.service loaded inactive dead Relabel all filesystems, i
rhel-configure.service loaded inactive dead Reconfigure the system on
rhel-dmesg.service loaded active exited Dump dmesg to /var/log/dme
rhel-import-state.service loaded active exited Import network configurati
rhel-loadmodules.service loaded inactive dead Load legacy module configu
rhel-readonly.service loaded active exited Configure read-only root s
rsyslog.service loaded active running System Logging Service
selinux-policy-migrate-local-changes@targeted.service loaded inactive dead M
● sendmail.service not-found inactive dead sendmail.service
● sntp.service not-found inactive dead sntp.service
sshd-keygen.service loaded inactive dead OpenSSH Server Key Generat
sshd.service loaded active running OpenSSH server daemon
● syslog.service not-found inactive dead syslog.service
systemd-ask-password-console.service loaded inactive dead Dispatch Password
systemd-ask-password-plymouth.service loaded inactive dead Forward Password
systemd-ask-password-wall.service loaded inactive dead Forward Password Requ
systemd-binfmt.service loaded inactive dead Set Up Additional Binary F
systemd-firstboot.service loaded inactive dead First Boot Wizard
systemd-fsck-root.service loaded inactive dead File System Check on Root
systemd-hwdb-update.service loaded inactive dead Rebuild Hardware Database
systemd-initctl.service loaded inactive dead /dev/initctl Compatibility
systemd-journal-catalog-update.service loaded inactive dead Rebuild Journal
systemd-journal-flush.service loaded active exited Flush Journal to Persiste
systemd-journald.service loaded active running Journal Service
systemd-logind.service loaded active running Login Service
systemd-machine-id-commit.service loaded inactive dead Commit a transient ma
systemd-modules-load.service loaded inactive dead Load Kernel Modules
● systemd-random-seed-load.service not-found inactive dead systemd-random-seed-lo
systemd-random-seed.service loaded active exited Load/Save Random Seed
systemd-readahead-collect.service loaded inactive dead Collect Read-Ahead Da
systemd-readahead-done.service loaded inactive dead Stop Read-Ahead Data Col
systemd-readahead-replay.service loaded inactive dead Replay Read-Ahead Data
systemd-reboot.service loaded inactive dead Reboot
systemd-remount-fs.service loaded active exited Remount Root and Kernel Fi
systemd-shutdownd.service loaded inactive dead Delayed Shutdown Service
systemd-sysctl.service loaded active exited Apply Kernel Variables
● systemd-sysusers.service not-found inactive dead systemd-sysusers.service
● systemd-timesyncd.service not-found inactive dead systemd-timesyncd.service
systemd-tmpfiles-clean.service loaded inactive dead Cleanup of Temporary Dir
systemd-tmpfiles-setup-dev.service loaded active exited Create Static Device
systemd-tmpfiles-setup.service loaded active exited Create Volatile Files an
systemd-udev-trigger.service loaded active exited udev Coldplug all Devices
systemd-udevd.service loaded active running udev Kernel Device Manager
systemd-update-done.service loaded inactive dead Update is Completed
systemd-update-utmp-runlevel.service loaded inactive dead Update UTMP about
systemd-update-utmp.service loaded active exited Update UTMP about System B
systemd-user-sessions.service loaded active exited Permit User Sessions
systemd-vconsole-setup.service loaded active exited Setup Virtual Console
tuned.service loaded active running Dynamic System Tuning Daem
vgauthd.service loaded active running VGAuth Service for open-vm
vmtoolsd.service loaded active running Service for virtual machin
LOAD = 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.
85 loaded units listed.
To show all installed unit files use 'systemctl list-unit-files'.
lines 78-93/93 (END)
DESCRIPTION：描述信息
SUB:是否running
ACTIVE:是否active
LOAD：是否load
不加—all则不会列出inactive（未激活状态）的service
[root@hyc-01-01 ~]# systemctl list-units --type=service
UNIT LOAD ACTIVE SUB DESCRIPTION
auditd.service loaded active running Security Auditing Service
chronyd.service loaded active running NTP client/server
crond.service loaded active running Command Scheduler
dbus.service loaded active running D-Bus System Message Bus
firewalld.service loaded active running firewalld - dynamic firewall d
getty@tty1.service loaded active running Getty on tty1
● kdump.service loaded failed failed Crash recovery kernel arming
kmod-static-nodes.service loaded active exited Create list of required static
network.service loaded active exited LSB: Bring up/down networking
NetworkManager-wait-online.service loaded active exited Network Manager Wait Onli
NetworkManager.service loaded active running Network Manager
polkit.service loaded active running Authorization Manager
postfix.service loaded active running Postfix Mail Transport Agent
rhel-dmesg.service loaded active exited Dump dmesg to /var/log/dmesg
rhel-import-state.service loaded active exited Import network configuration f
rhel-readonly.service loaded active exited Configure read-only root suppo
rsyslog.service loaded active running System Logging Service
sshd.service loaded active running OpenSSH server daemon
systemd-journal-flush.service loaded active exited Flush Journal to Persistent St
systemd-journald.service loaded active running Journal Service
systemd-logind.service loaded active running Login Service
systemd-random-seed.service loaded active exited Load/Save Random Seed
systemd-remount-fs.service loaded active exited Remount Root and Kernel File S
systemd-sysctl.service loaded active exited Apply Kernel Variables
systemd-tmpfiles-setup-dev.service loaded active exited Create Static Device Node
systemd-tmpfiles-setup.service loaded active exited Create Volatile Files and Dir
systemd-udev-trigger.service loaded active exited udev Coldplug all Devices
systemd-udevd.service loaded active running udev Kernel Device Manager
systemd-update-utmp.service loaded active exited Update UTMP about System Boot/
systemd-user-sessions.service loaded active exited Permit User Sessions
systemd-vconsole-setup.service loaded active exited Setup Virtual Console
tuned.service loaded active running Dynamic System Tuning Daemon
vgauthd.service loaded active running VGAuth Service for open-vm-too
vmtoolsd.service loaded active running Service for virtual machines h
LOAD = 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.
34 loaded units listed. Pass --all to see loaded but inactive units, too.
To show all installed unit files use 'systemctl list-unit-files'.
lines 27-42/42 (END)
这里显示的内容包含了target、service、socket，不仅是service
[root@hyc-01-01 ~]# systemctl list-unit-files
UNIT FILE STATE
proc-sys-fs-binfmt_misc.automount static
dev-hugepages.mount static
dev-mqueue.mount static
proc-sys-fs-binfmt_misc.mount static
sys-fs-fuse-connections.mount static
sys-kernel-config.mount static
sys-kernel-debug.mount static
tmp.mount disabled
brandbot.path disabled
systemd-ask-password-console.path static
systemd-ask-password-plymouth.path static
…
指定服务是否开机启动
[root@hyc-01-01 ~]# systemctl enable crond.service 开机启动
[root@hyc-01-01 ~]# systemctl disable crond.service 开机不启动
Removed symlink /etc/systemd/system/multi-user.target.wants/crond.service.
查看服务的状态
[root@hyc-01-01 ~]# systemctl status crond.service
● crond.service - Command Scheduler
Loaded: loaded (/usr/lib/systemd/system/crond.service; disabled; vendor preset: enabled)
Active: active (running) since 二 2018-07-17 20:51:53 CST; 10h ago
Main PID: 6851 (crond)
CGroup: /system.slice/crond.service
└─6851 /usr/sbin/crond -n
7月 17 20:51:53 hyc-01-01 systemd[1]: Started Command Scheduler.
7月 17 20:51:53 hyc-01-01 systemd[1]: Starting Command Scheduler...
7月 17 20:51:53 hyc-01-01 crond[6851]: (CRON) INFO (RANDOM_DELAY will be scale....)
7月 17 20:51:53 hyc-01-01 crond[6851]: (CRON) INFO (running with inotify support)
7月 17 20:51:53 hyc-01-01 crond[6851]: (CRON) INFO (@reboot jobs will be run a....)
7月 17 21:04:01 hyc-01-01 crond[6851]: (root) RELOAD (/var/spool/cron/root)
Hint: Some lines were ellipsized, use -l to show in full.
启动和停止服务
[root@hyc-01-01 ~]# systemctl stop crond 停止服务
[root@hyc-01-01 ~]# systemctl start crond 启动服务
[root@hyc-01-01 ~]# systemctl restart crond 重启服务
检测service是否开机启动
[root@hyc-01-01 ~]# systemctl is-enabled crond
disabled
crond实际为一个软链接，源文件在/usr/lib下，链接文件在/etc/systemd
[root@hyc-01-01 ~]# systemctl is-enabled crond
disabled
[root@hyc-01-01 ~]# ls /etc/systemd/system/multi-user.target.wants/crond.service
ls: 无法访问/etc/systemd/system/multi-user.target.wants/crond.service: 没有那个文件或目录
[root@hyc-01-01 ~]# systemctl enable crond
Created symlink from /etc/systemd/system/multi-user.target.wants/crond.service to /usr/lib/systemd/system/crond.service.
[root@hyc-01-01 ~]# ls /etc/systemd/system/multi-user.target.wants/crond.service
/etc/systemd/system/multi-user.target.wants/crond.service
10.26 unit介绍
10.27 target介绍
10.23 linux任务计划cron
linux任务计划配置文件
[root@hyc-01-01 ~]# cat /etc/crontab
SHELL=/bin/bash 文件中定义的shell
PATH=/sbin:/bin:/usr/sbin:/usr/bin 定义的环境变量（命令的路径）
MAILTO=root 给哪个用户发送邮件
# For details see man 4 crontabs
以下是任务计划的格式
# Example of job definition:
# .---------------- minute (0 - 59) 时间的分钟
# | .------------- hour (0 - 23) 时间的小时
# | | .---------- day of month (1 - 31) 一个月中的日期
# | | | .------- month (1 - 12) OR jan,feb,mar,apr ... 某个月（可以写数字或英文简写）
# | | | | .---- day of week (0 - 6) (Sunday=0 or 7) OR sun,mon,tue,wed,thu,fri,sat 星期几（0或7均表示周日）
# | | | | |
# * * * * * user-name command to be executed 用户 要执行的命令
定义一个任务计划
[root@hyc-01-01 ~]# crontab –e 用法同vim
no crontab for root - using an empty one
0 3 * * * /bin/bash /usr/local/sbin/123.sh>>/tmp/123.log 2>>/tmp/123.log
解释：在每月每周每日的3点执行shell脚本123.sh，将执行结果中正确的内容追加重定向到123.log文件，将执行结果中错误的内容也追加重定向到123.log文件
[root@hyc-01-01 ~]# crontab –e
no crontab for root - using an empty one
0 3 1-10 */2 2,5 /bin/bash /usr/local/sbin/123.sh>>/tmp/123.log 2>>/tmp/123.log
解释：在偶数月的1到10号的周二和周五的凌晨3点执行shell脚本
如何指定年份执行脚本？
每年的同一个日期的星期一定是不一样的，可以基于此确定脚本执行的年份
启动任务计划cron
[root@hyc-01-01 ~]# ps aux|grep cron
root 503 0.0 0.1 126264 1696 ? Ss 03:48 0:00 /usr/sbin/crond -n
root 6833 0.0 0.0 112676 984 pts/0 S+ 20:45 0:00 grep --color=auto cron
有上面的进程则说明服务已经启动
[root@hyc-01-01 ~]# systemctl status crond
● crond.service - Command Scheduler
Loaded: loaded (/usr/lib/systemd/system/crond.service; enabled; vendor preset: enabled)
Active: active (running) since 日 2018-07-15 22:05:31 CST; 1 day 22h ago
Main PID: 503 (crond)
CGroup: /system.slice/crond.service
└─503 /usr/sbin/crond -n
7月 15 22:05:31 hyc-01-01 systemd[1]: Started Command Scheduler.
7月 15 22:05:31 hyc-01-01 systemd[1]: Starting Command Scheduler...
7月 15 22:05:31 hyc-01-01 crond[503]: (CRON) INFO (RANDOM_DELAY will be scaled....)
7月 15 22:05:32 hyc-01-01 crond[503]: (CRON) INFO (running with inotify support)
Hint: Some lines were ellipsized, use -l to show in full.
以上active为active（running）且为绿色说明服务正常启动
[root@hyc-01-01 ~]# systemctl stop crond
[root@hyc-01-01 ~]# systemctl status crond
● crond.service - Command Scheduler
Loaded: loaded (/usr/lib/systemd/system/crond.service; enabled; vendor preset: enabled)
Active: inactive (dead) since 二 2018-07-17 20:50:11 CST; 2s ago
Main PID: 503 (code=exited, status=0/SUCCESS)
7月 15 22:05:31 hyc-01-01 systemd[1]: Started Command Scheduler.
7月 15 22:05:31 hyc-01-01 systemd[1]: Starting Command Scheduler...
7月 15 22:05:31 hyc-01-01 crond[503]: (CRON) INFO (RANDOM_DELAY will be scaled....)
7月 15 22:05:32 hyc-01-01 crond[503]: (CRON) INFO (running with inotify support)
7月 17 20:50:11 hyc-01-01 systemd[1]: Stopping Command Scheduler...
7月 17 20:50:11 hyc-01-01 systemd[1]: Stopped Command Scheduler.
Hint: Some lines were ellipsized, use -l to show in full.
此时crond服务未启动
crond任务计划中的脚本未执行的原因
有时脚本中用到的命令不在crond配置文件（/etc/crontab）定义的PATH路径中，导致找不到命令无法执行：
解决办法：
1 在配置文件的PATH路径中加入对应命令的路径
2 写任务计划时直接写命令的绝对路径
建议写任务计划时将执行的正确和错误结果重定向到文件，这样使执行过程有据可查，可以清楚的知道任务是否正确执行
-l 查看系统当前用户的任务计划
[root@hyc-01-01 ~]# crontab -l
0 3 * * * /bin/bash /usr/local/sbin/123.sh>>/tmp/123.log 2>>/tmp/123.log
crontab文件
[root@hyc-01-01 ~]# cat /var/spool/cron/root
0 3 * * * /bin/bash /usr/local/sbin/123.sh>>/tmp/123.log 2>>/tmp/123.log
该文件存放crontab –l命令显示的内容
10.24 chkconfig工具
chkconfig工具在centos6及更早的版本中常用，centos7不常用
查看当前系统中使用chkconfig工具的服务
[root@hyc-01-01 ~]# chkconfig --list
注：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。
要列出 systemd 服务，请执行 'systemctl list-unit-files'。
查看在具体 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
centos6及更早版本使用的服务管理机制叫SysV，centos7使用的服务管理机制为systemd；
centos7中的服务管理进程为systemd，centos6的服务管理进程为init；
[root@hyc-01-01 ~]# ls /etc/init.d 以上两个服务脚本的存放位置
functions netconsole network README
关闭network服务
[root@hyc-01-01 ~]# chkconfig network off
[root@hyc-01-01 ~]# chkconfig --list
注：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。
要列出 systemd 服务，请执行 'systemctl list-unit-files'。
查看在具体 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:关 3:关 4:关 5:关 6:关
以上0-6的开关表示在0-6的7个级别分别是什么状态，数字对应的开关表示开机启动或关闭
几个级别的状态：
0 关机状态
1 单用户模式
2 比3级别少了NFS服务
3 无图形化界面的多用户模式
4 保留级别
5 多用户带图形
6 重启
centos6及更早的版本通过修改/etc/inittab定义服务的运行级别，centos7中已不再使用
指定某一级别时关闭或开启服务
[root@hyc-01-01 ~]# chkconfig --level 3 network on
[root@hyc-01-01 ~]# chkconfig --list
注：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。
要列出 systemd 服务，请执行 'systemctl list-unit-files'。
查看在具体 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:关 3:开 4:关 5:关 6:关
[root@hyc-01-01 ~]# chkconfig --level 234 network on
[root@hyc-01-01 ~]# chkconfig --list
注：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。
要列出 systemd 服务，请执行 'systemctl list-unit-files'。
查看在具体 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:关 6:关
一般0/1/6级别服务关闭，其他级别服务可以选择性开启
将某个服务/脚本加入chkconfig列表
[root@hyc-01-01 init.d]# cp network 123 123作为新的脚本/服务
[root@hyc-01-01 init.d]# ls
123 functions netconsole network README
[root@hyc-01-01 init.d]# chkconfig --add 123 将123加入chkconfig服务列表
[root@hyc-01-01 init.d]# chkconfig --list
注：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。
要列出 systemd 服务，请执行 'systemctl list-unit-files'。
查看在具体 target 启用的服务请执行
'systemctl list-dependencies [target]'。
123 0:关 1:关 2:开 3:开 4:开 5:开 6:关
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:关 6:关
加入服务列表的要求：
1 将指定的脚本放到/etc/init.d目录下
2 文件名称无要求
3 文件内容为shell脚本
4 文件中必须有红字内容才能被识别
#! /bin/bash
#
# network Bring up/down networking
#
# chkconfig: 2345 10 90
# description: Activates/Deactivates all network interfaces configured to \
# start at boot time.
#
### BEGIN INIT INFO
…
从列表中删除某服务
[root@hyc-01-01 init.d]# chkconfig --del 123
[root@hyc-01-01 init.d]# chkconfig --list
注：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。
要列出 systemd 服务，请执行 'systemctl list-unit-files'。
查看在具体 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:关 6:关
10.25 systemd管理服务
systemd是centos7的服务管理机制
列出systemd中的service
[root@hyc-01-01 ~]# systemctl list-units --all --type=service
UNIT LOAD ACTIVE SUB DESCRIPTION
auditd.service loaded active running Security Auditing Service
brandbot.service loaded inactive dead Flexible Branding Service
chronyd.service loaded active running NTP client/server
cpupower.service loaded inactive dead Configure CPU power relate
crond.service loaded active running Command Scheduler
dbus.service loaded active running D-Bus System Message Bus
● display-manager.service not-found inactive dead display-manager.service
dracut-shutdown.service loaded inactive dead Restore /run/initramfs
ebtables.service loaded inactive dead Ethernet Bridge Filtering
emergency.service loaded inactive dead Emergency Shell
● exim.service not-found inactive dead exim.service
firewalld.service loaded active running firewalld - dynamic firewa
getty@tty1.service loaded active running Getty on tty1
ip6tables.service loaded inactive dead IPv6 firewall with ip6tabl
● ipset.service not-found inactive dead ipset.service
iptables.service loaded inactive dead IPv4 firewall with iptable
irqbalance.service loaded inactive dead irqbalance daemon
● kdump.service loaded failed failed Crash recovery kernel armi
kmod-static-nodes.service loaded active exited Create list of required st
microcode.service loaded inactive dead Load CPU microcode update
network.service loaded active exited LSB: Bring up/down network
NetworkManager-wait-online.service loaded active exited Network Manager Wait
NetworkManager.service loaded active running Network Manager
● ntpd.service not-found inactive dead ntpd.service
● ntpdate.service not-found inactive dead ntpdate.service
plymouth-quit-wait.service loaded inactive dead Wait for Plymouth Boot Scr
plymouth-quit.service loaded inactive dead Terminate Plymouth Boot Sc
plymouth-read-write.service loaded inactive dead Tell Plymouth To Write Out
plymouth-start.service loaded inactive dead Show Plymouth Boot Screen
polkit.service loaded active running Authorization Manager
postfix.service loaded active running Postfix Mail Transport Age
rc-local.service loaded inactive dead /etc/rc.d/rc.local Compati
rescue.service loaded inactive dead Rescue Shell
rhel-autorelabel-mark.service loaded inactive dead Mark the need to relabel
rhel-autorelabel.service loaded inactive dead Relabel all filesystems, i
rhel-configure.service loaded inactive dead Reconfigure the system on
rhel-dmesg.service loaded active exited Dump dmesg to /var/log/dme
rhel-import-state.service loaded active exited Import network configurati
rhel-loadmodules.service loaded inactive dead Load legacy module configu
rhel-readonly.service loaded active exited Configure read-only root s
rsyslog.service loaded active running System Logging Service
selinux-policy-migrate-local-changes@targeted.service loaded inactive dead M
● sendmail.service not-found inactive dead sendmail.service
● sntp.service not-found inactive dead sntp.service
sshd-keygen.service loaded inactive dead OpenSSH Server Key Generat
sshd.service loaded active running OpenSSH server daemon
● syslog.service not-found inactive dead syslog.service
systemd-ask-password-console.service loaded inactive dead Dispatch Password
systemd-ask-password-plymouth.service loaded inactive dead Forward Password
systemd-ask-password-wall.service loaded inactive dead Forward Password Requ
systemd-binfmt.service loaded inactive dead Set Up Additional Binary F
systemd-firstboot.service loaded inactive dead First Boot Wizard
systemd-fsck-root.service loaded inactive dead File System Check on Root
systemd-hwdb-update.service loaded inactive dead Rebuild Hardware Database
systemd-initctl.service loaded inactive dead /dev/initctl Compatibility
systemd-journal-catalog-update.service loaded inactive dead Rebuild Journal
systemd-journal-flush.service loaded active exited Flush Journal to Persiste
systemd-journald.service loaded active running Journal Service
systemd-logind.service loaded active running Login Service
systemd-machine-id-commit.service loaded inactive dead Commit a transient ma
systemd-modules-load.service loaded inactive dead Load Kernel Modules
● systemd-random-seed-load.service not-found inactive dead systemd-random-seed-lo
systemd-random-seed.service loaded active exited Load/Save Random Seed
systemd-readahead-collect.service loaded inactive dead Collect Read-Ahead Da
systemd-readahead-done.service loaded inactive dead Stop Read-Ahead Data Col
systemd-readahead-replay.service loaded inactive dead Replay Read-Ahead Data
systemd-reboot.service loaded inactive dead Reboot
systemd-remount-fs.service loaded active exited Remount Root and Kernel Fi
systemd-shutdownd.service loaded inactive dead Delayed Shutdown Service
systemd-sysctl.service loaded active exited Apply Kernel Variables
● systemd-sysusers.service not-found inactive dead systemd-sysusers.service
● systemd-timesyncd.service not-found inactive dead systemd-timesyncd.service
systemd-tmpfiles-clean.service loaded inactive dead Cleanup of Temporary Dir
systemd-tmpfiles-setup-dev.service loaded active exited Create Static Device
systemd-tmpfiles-setup.service loaded active exited Create Volatile Files an
systemd-udev-trigger.service loaded active exited udev Coldplug all Devices
systemd-udevd.service loaded active running udev Kernel Device Manager
systemd-update-done.service loaded inactive dead Update is Completed
systemd-update-utmp-runlevel.service loaded inactive dead Update UTMP about
systemd-update-utmp.service loaded active exited Update UTMP about System B
systemd-user-sessions.service loaded active exited Permit User Sessions
systemd-vconsole-setup.service loaded active exited Setup Virtual Console
tuned.service loaded active running Dynamic System Tuning Daem
vgauthd.service loaded active running VGAuth Service for open-vm
vmtoolsd.service loaded active running Service for virtual machin
LOAD = 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.
85 loaded units listed.
To show all installed unit files use 'systemctl list-unit-files'.
lines 78-93/93 (END)
DESCRIPTION：描述信息
SUB:是否running
ACTIVE:是否active
LOAD：是否load
不加—all则不会列出inactive（未激活状态）的service
[root@hyc-01-01 ~]# systemctl list-units --type=service
UNIT LOAD ACTIVE SUB DESCRIPTION
auditd.service loaded active running Security Auditing Service
chronyd.service loaded active running NTP client/server
crond.service loaded active running Command Scheduler
dbus.service loaded active running D-Bus System Message Bus
firewalld.service loaded active running firewalld - dynamic firewall d
getty@tty1.service loaded active running Getty on tty1
● kdump.service loaded failed failed Crash recovery kernel arming
kmod-static-nodes.service loaded active exited Create list of required static
network.service loaded active exited LSB: Bring up/down networking
NetworkManager-wait-online.service loaded active exited Network Manager Wait Onli
NetworkManager.service loaded active running Network Manager
polkit.service loaded active running Authorization Manager
postfix.service loaded active running Postfix Mail Transport Agent
rhel-dmesg.service loaded active exited Dump dmesg to /var/log/dmesg
rhel-import-state.service loaded active exited Import network configuration f
rhel-readonly.service loaded active exited Configure read-only root suppo
rsyslog.service loaded active running System Logging Service
sshd.service loaded active running OpenSSH server daemon
systemd-journal-flush.service loaded active exited Flush Journal to Persistent St
systemd-journald.service loaded active running Journal Service
systemd-logind.service loaded active running Login Service
systemd-random-seed.service loaded active exited Load/Save Random Seed
systemd-remount-fs.service loaded active exited Remount Root and Kernel File S
systemd-sysctl.service loaded active exited Apply Kernel Variables
systemd-tmpfiles-setup-dev.service loaded active exited Create Static Device Node
systemd-tmpfiles-setup.service loaded active exited Create Volatile Files and Dir
systemd-udev-trigger.service loaded active exited udev Coldplug all Devices
systemd-udevd.service loaded active running udev Kernel Device Manager
systemd-update-utmp.service loaded active exited Update UTMP about System Boot/
systemd-user-sessions.service loaded active exited Permit User Sessions
systemd-vconsole-setup.service loaded active exited Setup Virtual Console
tuned.service loaded active running Dynamic System Tuning Daemon
vgauthd.service loaded active running VGAuth Service for open-vm-too
vmtoolsd.service loaded active running Service for virtual machines h
LOAD = 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.
34 loaded units listed. Pass --all to see loaded but inactive units, too.
To show all installed unit files use 'systemctl list-unit-files'.
lines 27-42/42 (END)
这里显示的内容包含了target、service、socket，不仅是service
[root@hyc-01-01 ~]# systemctl list-unit-files
UNIT FILE STATE
proc-sys-fs-binfmt_misc.automount static
dev-hugepages.mount static
dev-mqueue.mount static
proc-sys-fs-binfmt_misc.mount static
sys-fs-fuse-connections.mount static
sys-kernel-config.mount static
sys-kernel-debug.mount static
tmp.mount disabled
brandbot.path disabled
systemd-ask-password-console.path static
systemd-ask-password-plymouth.path static
…
指定服务是否开机启动
[root@hyc-01-01 ~]# systemctl enable crond.service 开机启动
[root@hyc-01-01 ~]# systemctl disable crond.service 开机不启动
Removed symlink /etc/systemd/system/multi-user.target.wants/crond.service.
查看服务的状态
[root@hyc-01-01 ~]# systemctl status crond.service
● crond.service - Command Scheduler
Loaded: loaded (/usr/lib/systemd/system/crond.service; disabled; vendor preset: enabled)
Active: active (running) since 二 2018-07-17 20:51:53 CST; 10h ago
Main PID: 6851 (crond)
CGroup: /system.slice/crond.service
└─6851 /usr/sbin/crond -n
7月 17 20:51:53 hyc-01-01 systemd[1]: Started Command Scheduler.
7月 17 20:51:53 hyc-01-01 systemd[1]: Starting Command Scheduler...
7月 17 20:51:53 hyc-01-01 crond[6851]: (CRON) INFO (RANDOM_DELAY will be scale....)
7月 17 20:51:53 hyc-01-01 crond[6851]: (CRON) INFO (running with inotify support)
7月 17 20:51:53 hyc-01-01 crond[6851]: (CRON) INFO (@reboot jobs will be run a....)
7月 17 21:04:01 hyc-01-01 crond[6851]: (root) RELOAD (/var/spool/cron/root)
Hint: Some lines were ellipsized, use -l to show in full.
启动和停止服务
[root@hyc-01-01 ~]# systemctl stop crond 停止服务
[root@hyc-01-01 ~]# systemctl start crond 启动服务
[root@hyc-01-01 ~]# systemctl restart crond 重启服务
检测service是否开机启动
[root@hyc-01-01 ~]# systemctl is-enabled crond
disabled
crond实际为一个软链接，源文件在/usr/lib下，链接文件在/etc/systemd
[root@hyc-01-01 ~]# systemctl is-enabled crond
disabled
[root@hyc-01-01 ~]# ls /etc/systemd/system/multi-user.target.wants/crond.service
ls: 无法访问/etc/systemd/system/multi-user.target.wants/crond.service: 没有那个文件或目录
[root@hyc-01-01 ~]# systemctl enable crond
Created symlink from /etc/systemd/system/multi-user.target.wants/crond.service to /usr/lib/systemd/system/crond.service.
[root@hyc-01-01 ~]# ls /etc/systemd/system/multi-user.target.wants/crond.service
/etc/systemd/system/multi-user.target.wants/crond.service
10.26 unit介绍
10.27 target介绍
