puppet学习与精通之－Exec资源详细介绍及案例分析

一、系统环境

1、puppet服务端

Release：RHEL6.4
HOSTNAME: puppetserver.rsyslog.org
TCP/IP: 172.16.200.100/24
Packages：
puppet-server-2.7.21-1.el6.noarch
mcollective-client-2.2.4
activemq-5.5.0
2、puppet节点
Release: RHEL5.8
HOSTNAME: agent1.rsyslog.org
TCP/IP: 172.16.200.101/24
Packages:
puppet-2.7.21-1.el5
mcollective-2.2.4-1.el5
3、puppet节点
Release: RHEL6.4
HOSTNAME: agent3.rsyslog.org
TCP/IP: 172.16.200.103/24
Packages:
puppet-2.7.21-1.el6
mcollective-2.2.4-1.el6

二、资源介绍
1、实现功能
1.1 远程执行系统命令，其实就是shell的调用
1.2 由于exec是一次性执行资源，在不同类里面exec名字可相同。
2、支持参数
2.1 command => "mkdir /tmp/rhel5/nginx ", 被执行的命令，必须为被执行命令的绝对路径。

2.2 cwd =>"/tmp/rhel5/nginx", 指定命令执行的目录。如果目录不存在，则命令执行失败。

2.3 environment => "PATH=/home/puppetfans", 为命令设定额外的环境变量。要注意的是如果你用这个来设定PATH，那么PATH的属性会被覆盖。多个环境变量应该以数组的形式来设定。

2.4 group =>  定义运行命令的用户组。在不同的平台下的运行的结果无法确定，由于不同用户运行命令的时候，变量是不变的，所以这是平台的问题，而不是Ruby或Puppet的问题。

2.5 logoutput => on_failure|true|false  是否记录输出。默认会根据exec资源的日志等级（loglevel） 来记录输出。若定义为on_failure，则仅在命令返回错误的时候记录输出。可取的值为：true，false和其他合法的日志等级。

2.6 onlyif =>"/bin/ls /usr/local/nginx/conf", 如果这个参数被设定了，则exec只会在onlyif设定的命令返回0时才执行。

2.7 path => [ "/bin/", "/sbin/" , "/usr/bin/", "/usr/sbin/" ] 命令执行的搜索路径。如果path没有被定义，命令需要使用绝对路径。路径可以以数组或以冒号分隔的形式来定义。

2.8 creates => "/tmp/rhel5/nginx", 指定命令所生成的文件。如果提供了这个参数，那么命令只会在所指定的文件不存在的情况的被执行：

2.9 refresh =>true|false 定义如何更新命令。当exec收到一个来自其他资源的事件时，默认只会重新执行一次命令。不过这个参数允许你定义更新时执行不同的命令。

2.10 refreshonly =>true|false 该属性可以使命令变成仅刷新触发的，也就是说只有在一个依赖的对象被改变时，命令才会被执行。只有同时使用subscribe或notify才有意义

2.11 returns 指定返回的代码。如果被执行的命令返回了其他的代码，一个错误（error）会被返回。默认值是0，可以定义为一个由可以接受的返回代码组成的数组或单值。

2.12 timeout => 0 命令运行的最长时间。如果命令运行的时间超过了timeout定义的时间，那么这个命令就会被终止，并作为运行失败处理。当定义为负值时就会取消运行时间的限制。timeout的值是以秒为单位的。

2.13 unless => "/bin/ls /usr/local/nginx/conf",如果这个变量被指定了，那么exec会执行，除非unless所设定的命令返回0

2.14 user => "nginx",  定义运行命令的用户。 注意如果你使用了这个参数，那么任何的错误输出不会在当下被捕捉，这是Ruby的一个bug。

三、资源示例
1、示例一
1.1 实现功能
*要求实现使用chkconfig命令将节点的iptables和ip6tables服务关闭，并记录错误日志
1.2 配置说明

class motd::exec {
        include motd::exec1
}
class motd::exec1 {
        exec {  [  "chkconfig iptables off",
                   "chkconfig ip6tables off",]:
                path  => ["/usr/bin","/usr/sbin","/bin","/sbin"],
                logoutput => on_failure,
        }
}

1.3 客户端agent3测试

[root@agent3 ~]# puppet agent --test
info: Retrieving plugin
info: Loading facts in /var/lib/puppet/lib/facter/backup_date.rb
info: Loading facts in /var/lib/puppet/lib/facter/my_apply1.rb
info: Loading facts in /var/lib/puppet/lib/facter/my_apply3.rb
info: Loading facts in /var/lib/puppet/lib/facter/my_apply2.rb
info: Caching catalog for agent3.rsyslog.org
info: Applying configuration version '1378284783'
notice: /Stage[main]/Motd::Exec1/Exec[chkconfig iptables off]/returns: executed successfully
notice: /Stage[main]/Motd::Exec1/Exec[chkconfig ip6tables off]/returns: executed successfully
notice: Finished catalog run in 0.17 seconds

2、示例二
2.1 实现功能
*要求节点上创建用户和组nginx，UID和GID都为1000
*要求从服务器下载nginx-0.8.42.tar.gz源码包到节点/tmp/rhel5/nginx目录下
*要求解压源码包，并编译安装到指定目录下
2.2 配置说明

class source {
    include source::file1,source::exec1,source::exec2,source::exec3,source::user
    notify { "nstallation nginx package through the source code nginx-0.8.42.tar.gz":
           withpath => true,
        }
}
class source::user{
    group { "nginx":   #建立组nginx
            ensure => present,
            gid => 1000
}
    user { "nginx":   #建立用户nginx
            ensure => present,
            uid => 1000,
                gid => 1000,
            groups => ["nginx"],
#           membership => minimum,
            shell => "/sbin/nologin",
            require => Group["nginx"]
    }
}
class source::file1{  #远程下载nginx源码包
    file{ "nginx":
        name => "/tmp/rhel5/nginx/nginx-0.8.42.tar.gz",
        owner => "root",
                group => "root",
                mode => 0700,
                source => "puppet://$puppetserver/modules/source/nginx-0.8.42.tar.gz",
                backup => 'main',
                require => Class["source::exec1"],
        }
}
class source::exec1{
    exec {"create nginx_pag":
        command => "mkdir /tmp/rhel5/nginx ",
        path => ["/usr/bin","/usr/sbin","/bin","/sbin"],
        creates => "/tmp/rhel5/nginx", #目录或文件不存在的情况下执行command
    }
}
class source::exec2{
    exec { "install nginx":
        cwd =>"/tmp/rhel5/nginx",  #目录存在的情况下执行command
            command =>"tar -zxvf nginx-0.8.42.tar.gz && cd nginx-0.8.42 &&./configure --user=nginx --group=nginx --prefix=/usr/local/nginx --without-http-cache && make&&make install",
        path => ["/usr/bin","/usr/sbin","/bin","/sbin"],
        logoutput => on_failure,
        unless => "/bin/ls /usr/local/nginx/conf",  #命令返回值不为0的情况下执行commond
        require => Class[source::file1,source::user]
        notify => Class["source::exec3"],
    }
}
class source::exec3{
    exec { "updatedb":
        command => "updatedb",
        path => ["/usr/bin","/usr/sbin","/bin","/sbin"],
        refreshonly => true,  #触发更新的时候执行command
        subscribe => Class["source::exec2"],
    }
}
[root@puppetserver manifests]#

2.3 客户端agent3测试

第一次执行：

测试前：

[root@agent3 rhel5]# cat /etc/passwd | grep nginx
[root@agent3 rhel5]# cat /etc/group | grep nginx
[root@agent3 rhel5]# ll /tmp/rhel5/
total 0
[root@agent3 rhel5]# ll /usr/local/ |  grep nginx

测试中：

[root@agent3 ~]# puppet agent --test
info: Retrieving plugin
info: Loading facts in /var/lib/puppet/lib/facter/backup_date.rb
info: Loading facts in /var/lib/puppet/lib/facter/my_apply1.rb
info: Loading facts in /var/lib/puppet/lib/facter/my_apply3.rb
info: Loading facts in /var/lib/puppet/lib/facter/my_apply2.rb
info: Caching catalog for agent3.rsyslog.org
info: Applying configuration version '1378366520'
notice: /Stage[main]/Source::Exec1/Exec[create nginx_pag]/returns: executed successfully
notice: /Stage[main]/Source/Notify[nstallation nginx package through the source code nginx-0.8.42.tar.gz]/message: nstallation nginx package through the source code nginx-0.8.42.tar.gz
notice: /Stage[main]/Source/Notify[nstallation nginx package through the source code nginx-0.8.42.tar.gz]/message: defined 'message' as 'nstallation nginx package through the source code nginx-0.8.42.tar.gz'
notice: /Stage[main]/Source::File1/File[nginx]/ensure: defined content as '{md5}2818e8b03512b239f1238d702703bcf3'
notice: /Stage[main]/Source::User/Group[nginx]/ensure: created
notice: /Stage[main]/Source::User/User[nginx]/ensure: created
notice: /Stage[main]/Source::Exec2/Exec[install nginx]/returns: executed successfully
info: /Stage[main]/Source::Exec2/Exec[install nginx]: Scheduling refresh of Class[Source::Exec3]
info: Class[Source::Exec2]: Scheduling refresh of Exec[updatedb]
info: Class[Source::Exec3]: Scheduling refresh of Exec[updatedb]
notice: /Stage[main]/Source::Exec3/Exec[updatedb]: Triggered 'refresh' from 2 events
notice: Finished catalog run in 18.83 seconds

测试后：

[root@agent3 rhel5]# cat /etc/passwd | grep nginx
nginx:x:1000:1000::/home/nginx:/sbin/nologin
[root@agent3 rhel5]# cat /etc/group | grep nginx
nginx:x:1000:nginx
[root@agent3 rhel5]# ll /tmp/rhel5/nginx/
total 632
drwxr-xr-x. 8 nginx nginx   4096 Sep  5 14:29 nginx-0.8.42
-rwx------. 1 root  root  642593 Sep  5 14:29 nginx-0.8.42.tar.gz
[root@agent3 rhel5]# ll /usr/local/nginx/
total 16
drwxr-xr-x. 2 root root 4096 Sep  5 14:30 conf
drwxr-xr-x. 2 root root 4096 Sep  5 14:30 html
drwxr-xr-x. 2 root root 4096 Sep  5 14:30 logs
drwxr-xr-x. 2 root root 4096 Sep  5 14:30 sbin

第二次执行：

由于设置了 unless => "/bin/ls /usr/local/nginx/conf", 当命令返回结果为0的时候，exec是不会执行的。其次设置了refreshonly => true,配合notify和subscrive只有在更改的情况下才会触发更新

[root@agent3 ~]# puppet agent --test
info: Retrieving plugin
info: Loading facts in /var/lib/puppet/lib/facter/backup_date.rb
info: Loading facts in /var/lib/puppet/lib/facter/my_apply1.rb
info: Loading facts in /var/lib/puppet/lib/facter/my_apply3.rb
info: Loading facts in /var/lib/puppet/lib/facter/my_apply2.rb
info: Caching catalog for agent3.rsyslog.org
info: Applying configuration version '1378366520'
notice: /Stage[main]/Source/Notify[nstallation nginx package through the source code nginx-0.8.42.tar.gz]/message: nstallation nginx package through the source code nginx-0.8.42.tar.gz
notice: /Stage[main]/Source/Notify[nstallation nginx package through the source code nginx-0.8.42.tar.gz]/message: defined 'message' as 'nstallation nginx package through the source code nginx-0.8.42.tar.gz'
notice: Finished catalog run in 0.32 seconds