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Linux 服务脚本

一、Linux 开机自动启动服务

​ linux开机服务原理：

​ ①linux系统启动首先加载kernel

​ ②初始操作系统

​ ③login验证程序等待用户登陆

​ 初始化操作系统

​ kernel加载/sbin/init创建用户空间的第一个程序

​ 该程序完成操作系统的初始化：

​ /etc/inittab文件是/sbin/init程序读取的配置文件

# inittab is no longer used when using systemd.
#
# ADDING CONFIGURATION HERE WILL HAVE NO EFFECT ON YOUR SYSTEM.
#
# Ctrl-Alt-Delete is handled by /usr/lib/systemd/system/ctrl-alt-del.target
#
# systemd uses 'targets' instead of runlevels. By default, there are two main targets:
#
# multi-user.target: analogous to runlevel 3
# graphical.target: analogous to runlevel 5
#
# To view current default target, run:
# systemctl get-default
#
# To set a default target, run:
# systemctl set-default TARGET.target
#

​ 0-6,6个级别,每种级别之间的差异其实就是启动脚本的种类数量不同而已

级别	含义
0	halt(Do NOT set initdefault to this)
1	Single user mode
2	Multiuser，without NFS (The same as 3, if you do not have networking)
3	Full multiuser mode
4	unused
5	X11
6	reboot(Do NOT set initdefault to this)

​ 每个级别对应在/etc/rc.d下都有自己的目录

[root@localhost ~]# ls -l /etc/rc.d
total 4
drwxr-xr-x. 2 root root  70 May 15 23:05 init.d
drwxr-xr-x. 2 root root  45 Nov 16  2020 rc0.d
drwxr-xr-x. 2 root root  45 Nov 16  2020 rc1.d
drwxr-xr-x. 2 root root  45 Nov 16  2020 rc2.d
drwxr-xr-x. 2 root root  45 Nov 16  2020 rc3.d
drwxr-xr-x. 2 root root  45 Nov 16  2020 rc4.d
drwxr-xr-x. 2 root root  45 Nov 16  2020 rc5.d
drwxr-xr-x. 2 root root  45 Nov 16  2020 rc6.d
-rw-r--r--. 1 root root 473 Dec  7  2023 rc.local

​ /etc/rc.d目录：

​ init.d目录是所有的原始服务脚本

​ rc*.d目录中是对init.d目录中脚本的软连接

[root@localhost ~]# ls -l /etc/rc.d/rc3.d
total 0
lrwxrwxrwx. 1 root root 20 Apr 17 04:27 K50netconsole -> ../init.d/netconsole
lrwxrwxrwx. 1 root root 17 Apr 17 04:27 S10network -> ../init.d/network

二、Linux 服务管理操作

​ 不同级别中服务脚本的管理命令

​ chkconfig

​ chkconfig-updates and queries runlevelinformation for system services

​ 服务进程的管理命令

​ service

​ service -run a System V init scrip

​ chkconfig [--list] [--type type][name]

​ 显示系统服务,以及各个级别开关状态

[root@localhost ~]# chkconfig --listNote: This output shows SysV services only and does not include nativesystemd services. SysV configuration data might be overridden by nativesystemd configuration.If you want to list systemd services use 'systemctl list-unit-files'.To see services enabled on particular target use'systemctl list-dependencies [target]'.netconsole     	0:off	1:off	2:off	3:off	4:off	5:off	6:off
network        	0:off	1:off	2:on	3:on	4:on	5:on	6:off

​ chkconfig --del name

​ 去除系统启动管理服务中的服务

# 删除服务
[root@localhost ~]# chkconfig --del network# 已经被删除
[root@localhost ~]# chkconfig --list networkNote: This output shows SysV services only and does not include nativesystemd services. SysV configuration data might be overridden by nativesystemd configuration.If you want to list systemd services use 'systemctl list-unit-files'.To see services enabled on particular target use'systemctl list-dependencies [target]'.service network supports chkconfig, but is not referenced in any runlevel (run 'chkconfig --add network')

​ chkconfig --add name

​ 添加系统服务,且服务脚本要在/etc/rc.d/init.d目录下

# 添加服务
[root@localhost ~]# chkconfig --add network# 查看是否添加
[root@localhost ~]# chkconfig --list networkNote: This output shows SysV services only and does not include nativesystemd services. SysV configuration data might be overridden by nativesystemd configuration.If you want to list systemd services use 'systemctl list-unit-files'.To see services enabled on particular target use'systemctl list-dependencies [target]'.network        	0:off	1:off	2:on	3:on	4:on	5:on	6:off

​ chkconfig [--level levels] [--type type] name <on|off|reset|resetpriorities>

​ 调整系统启动管理服务中的服务级别

# 将network在启动级别为1设置不启动
[root@localhost ~]# chkconfig --level 1 network on# 查看是否关闭
[root@localhost ~]# chkconfig --listNote: This output shows SysV services only and does not include nativesystemd services. SysV configuration data might be overridden by nativesystemd configuration.If you want to list systemd services use 'systemctl list-unit-files'.To see services enabled on particular target use'systemctl list-dependencies [target]'.netconsole     	0:off	1:off	2:off	3:off	4:off	5:off	6:off
network        	0:off	1:on	2:on	3:on	4:on	5:on	6:off

​ service SCRIPT COMMAND

​ SCRIPT：系统服务脚本名称,在/etc/rc.d/init.d或软连接的目录/etc/init.d目录中

​ COMMAND:脚本不同,但是基本包含{start|stop|status|restart|reload}

​ service --status-all

​ service network restart

# 查看network服务状态
[root@localhost ~]# service network status
Configured devices:
lo ens33
Currently active devices:
lo ens33

​ Linux系统服务脚本：

​ vi /etc/init.d/network

​ 脚本中必须包含以下两行

​ # chkconfig: 2345 10 90

​ 被注释的,表示调用chkconfig操作add时默认的各级别开启

​ 10:表示启动级别:先启动后关闭,最大值99

​ 90:表示停止级别:先启动后关闭,最大值99

​ # description: Activates/Deactivates all network interfaces configured to \

​ # start at boot time.

#! /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
# Provides: $network
# Should-Start: iptables ip6tables NetworkManager-wait-online NetworkManager $network-pre
# Short-Description: Bring up/down networking
# Description: Bring up/down networking
### END INIT INFO# Source function library.
. /etc/init.d/functions
……

​ 可以看到相应级别目录中的脚本名称前面包含K或S和一个数值

​ K：关闭服务，后面的数值是关闭优先级

​ S：启动服务，后面的数值是启动优先级

[root@localhost ~]# ls -l /etc/rc.d/rc3.d/
total 0
lrwxrwxrwx. 1 root root 20 Apr 17 04:27 K50netconsole -> ../init.d/netconsole
lrwxrwxrwx. 1 root root 17 Oct 16 08:26 S10network -> ../init.d/network

三、tomcat服务脚本

​ 安装java

# 下载java1.8
[root@localhost ~]# yum -y install java-1.8.0*# 验证是否安装成功
[root@localhost ~]# java -version
openjdk version "1.8.0_412"
OpenJDK Runtime Environment (build 1.8.0_412-b08)
OpenJDK 64-Bit Server VM (build 25.412-b08, mixed mode)

​ bash以交互方式启动时会加载/etc/profile文件,所以在这里定义的环境变量能被用户交互时用到,用户交互启动程序所依赖•

​ 但是系统服务脚本优先在用户登陆前启动,且不会读取/etc/profile

# 下载tomcat9.0
[root@localhost ~]# wget https://dlcdn.apache.org/tomcat/tomcat-9/v9.0.96/bin/apache-tomcat-9.0.96.tar.gz# 解压文件
[root@localhost ~]# tar -xzvf apache-tomcat-9.0.96.tar.gz # 进入tomcat/bin
[root@localhost ~]# cd apache-tomcat-9.0.96/bin# 启动服务
[root@localhost bin]# ./startup.sh
Using CATALINA_BASE:   /root/apache-tomcat-9.0.96
Using CATALINA_HOME:   /root/apache-tomcat-9.0.96
Using CATALINA_TMPDIR: /root/apache-tomcat-9.0.96/temp
Using JRE_HOME:        /usr
Using CLASSPATH:       /root/apache-tomcat-9.0.96/bin/bootstrap.jar:/root/apache-tomcat-9.0.96/bin/tomcat-juli.jar
Using CATALINA_OPTS:   
Tomcat started.# 查看运行进程
[root@localhost bin]# ps -ef | grep java
root       1648      1 25 11:07 pts/0    00:00:03 /usr/bin/java -Djava.util.logging.config.file=/root/apache-tomcat-9.0.96/conf/logging.properties -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager -Djdk.tls.ephemeralDHKeySize=2048 -Djava.protocol.handler.pkgs=org.apache.catalina.webresources -Dorg.apache.catalina.security.SecurityListener.UMASK=0027 -Dignore.endorsed.dirs= -classpath /root/apache-tomcat-9.0.96/bin/bootstrap.jar:/root/apache-tomcat-9.0.96/bin/tomcat-juli.jar -Dcatalina.base=/root/apache-tomcat-9.0.96 -Dcatalina.home=/root/apache-tomcat-9.0.96 -Djava.io.tmpdir=/root/apache-tomcat-9.0.96/temp org.apache.catalina.startup.Bootstrap start
root       1676   1371  0 11:08 pts/0    00:00:00 grep --color=auto java# 关闭防火墙
[root@localhost bin]# systemctl stop firewalld
[root@localhost bin]# setenforce 0# 浏览器访问http://your_ip:8080# 停止服务
[root@localhost bin]# ./shutdown.sh

​ 但是这种运行方式需要用户干预,我们更希望的是服务器启动后能将tomcat作为系统服务启动

​ 我们自己实现一个tomcat的系统服务脚本

​ 对于service调取脚本可以传递给脚本的参数应该包含：

​ start

​ stop

​ restart

​ status

​ 作为服务脚本必须实现的内容：

​ # chkconfig: 123456 2079

​ # description: This is a Tomcat Server shell scripts

​ 另外,系统还有一个通用的工具脚本,其中包含了一些方便我们服务脚本开发的函数

​ . /etc/rc.d/init.d/functions

# 创建tomcat
[root@localhost bin]# touch /etc/init.d/tomcat# 添加执行权
[root@localhost bin]# chmod +x /etc/init.d/tomcat[root@localhost bin]# vi /etc/init.d/tomcat
#!/bin/bash
#
# chkconfig: 123456 2079
# description: This is a Tomcat Server shell scripts
. /etc/rc.d/init.d/functions

​ etc/rc.d/init.d/functions脚本介绍：

​ functions这个脚本是给/etc/init.d里边的文件使用的,提供了一些基础的功能

​ 重要函数：

​ checkpid:检查是否已存在pid，如果有一个存在，返回0（通过查看/proc目录）

​ daemon:启动某个服务。/etc/init.d目录部分脚本的start使用到这个

​ killproc:杀死某个进程。/etc/init.d目录部分脚本的stop使用到这个

​ status:返回一个服务的状态

​ 我们可以在自己的脚本中通过source或.的方式导入

​ tomcat有自己的服务管理脚本

​ 在系统服务脚本中判断服务进程状态

​ 最直接的方式是用进程的PID

​ 观察：bin/startup.sh

​ 发现最终调用catalina.sh脚本

​ 并传参start

​ 所以查找catalina.sh

​ 查找到这行：

​ elif [ "$1" = "start" ] ; then

​ 向下寻找到分支结束前，添加：

​ echo "CATALINA_PID:$!

# 打印pid
[root@localhost bin]# vi startup.sh
# 第519行，添加
echo "CATALINA_PID:$!"# 返回编写tomcat
[root@localhost bin]# vi /etc/init.d/tomcat
#!/bin/bash
#
# chkconfig: 123456 2079
# description: This is a Tomcat Server shell scripts
. /etc/rc.d/init.d/functions
tom_home=/root/apache-tomcat-9.0.96/bin
# tomcat启动后将进程ID存在这个文件中
tom_lock_file=/var/lock/subsys/tom.lock
tom_status(){if [ -f $tom_lock_file ]; thenlock_pid=`cat $tom_lock_file`if [ ! -z $lock_pid ];then# 调用函数来检测PID对应的进程是否存在if checkpid `cat $tom_lock_file`; thenecho "tomcat is running( $lock_pid )..." && return 0elseecho "tomcat ( $lock_pid )is not running but lock_fileexist" && return 1fififiecho "tomcat is not running ......"  && return 2
}
tom_start(){if ! tom_status >& /dev/null ; then# 这里启动tomcat,并获取pid存到锁文件中$tom_home/startup.sh |& grep "CATALINA_PID:" | sed 's/CATALINA_PID:\(.*\)/\1/' > $tom_lock_fileecho "tomcat started ..."fitom_status
}
tom_stop(){tom_status$tom_home/shutdown.sh >& /dev/nullecho "tomcat stoped..."echo '' > $tom_lock_file
}
tom_restart()
{tom_stopsleep 1tom_start
}
case $1 instatus)tom_status;;start)tom_start;;stop)tom_stop;;restart)tom_restart;;*)echo $"Usage: $0 {start|stop|status|restart}";;
esac

​ 设置开机自启动

[root@localhost bin]# chkconfig --level 3 tomcat on