Introduction To Ad-Hoc Commands:

Introduction To Ad-Hoc Commands:

在下面的例子中,我们将演示如何使用 /usr/bin/ansible 运行 ad hoc 任务.


所谓ad-hoc 命令是什么呢？

(这其实是一个概念性的名字,是相对于写Ansible playbook 来说的.类似于在命令行敲入shell命令和

写shell scripts两者之间的关系)


如果我们敲入一些命令比较快的完成一些事情,而不需要将这些执行的命令特别保存下来,这样的命令就叫做ad-hoc命令:


Ansible提供两种方式去完成任务,一是ad-hoc命令,一是写Andisble playbook前者可以解决一些简单的任务,

后者解决较复杂的任务。


Parallelism and Shell Commands

并行和shell命令:

这里我们要使用Ansible的命令行工具来重启Atlanta组中所有的web服务器,每次重启10个:

  -u REMOTE_USER, --user=REMOTE_USER
                        connect as this user (default=root)


[root@node01 ~]# ansible webservers -a hostname
192.168.137.3 | SUCCESS | rc=0 >>
node2

[root@node01 ~]# ansible webservers -a hostname -u root
192.168.137.3 | SUCCESS | rc=0 >>
node2

[root@node01 ~]# ansible webservers -a hostname -u mqm
192.168.137.3 | UNREACHABLE! => {
    "changed": false, 
    "msg": "Failed to connect to the host via ssh: Permission denied (publickey,gssapi-keyex,gssapi-with-mic,password).
", 
    "unreachable": true
}


在前面写出的命令中, -f 10 选项表示使用10个并行的进程。这个选项可以在 Ansible的配置文件 中

设置,在配置文件中指定的话,就不用在命令行中写出了。


ansible 有许多模块默认是'command',也就是命令模块,我们可以通过-m选项来指定不同的模块。


在前面所示的例子中,因为我们是要在Atlanta组下的服务器中执行reboot命令



command 模块不支持shell变量,也不支持管道等shell相关的东西。如果你想使用shell相关的这些东西,

请使用'shell'模块,两个模块之前的差别请参考


Fiel Transfer:

这是/usr/bin/ansible的另一种用法,Ansible能够以并行的方式同时SCP大量的文件到多台机器

$ ansible atlanta -m copy -a "src=/etc/hosts dest=/tmp/hosts"


[root@node01 ~]# ansible webservers -m copy -a "src=/etc/hosts dest=/tmp/hosts"
192.168.137.3 | SUCCESS => {
    "changed": true, 
    "checksum": "a3d4bc64e2b269bffe14ec2e19308541b1d8d183", 
    "dest": "/tmp/hosts", 
    "failed": false, 
    "gid": 0, 
    "group": "root", 
    "md5sum": "b269d2b01e6746e5310b7f7d5e699735", 
    "mode": "0644", 
    "owner": "root", 
    "size": 181, 
    "src": "/root/.ansible/tmp/ansible-tmp-1510552624.24-224464626846698/source", 
    "state": "file", 
    "uid": 0
}

此时的权限为root:root:


node2:/root#ls -ltr /tmp/
total 16
drwx------ 3 root root 4096 Oct  9 01:15 par-726f6f74
lrwxrwxrwx 1 root root   24 Nov 13 00:39 mysql.sock -> /data01/mysql/mysql.sock
-rw-r--r-- 1 root root   11 Dec  4 00:18 hello.world
drwx------ 2 root root 4096 Dec  6 05:51 pip-EHe6bt-unpack
-rw-r--r-- 1 root root  181 Dec  9 18:35 hosts



使用file 模块可以做到修改文件的属主和权限(在这里是可替换为copy模块,是等效的):


[root@node01 ~]# ansible webservers -m file -a "src=/etc/hosts dest=/tmp/hosts mode=600"
192.168.137.3 | SUCCESS => {
    "changed": true, 
    "failed": false, 
    "gid": 0, 
    "group": "root", 
    "mode": "0600", 
    "owner": "root", 
    "path": "/tmp/hosts", 
    "size": 181, 
    "state": "file", 
    "uid": 0
}


node2:/root#ls -ltr /tmp/
total 16
drwx------ 3 root root 4096 Oct  9 01:15 par-726f6f74
lrwxrwxrwx 1 root root   24 Nov 13 00:39 mysql.sock -> /data01/mysql/mysql.sock
-rw-r--r-- 1 root root   11 Dec  4 00:18 hello.world
drwx------ 2 root root 4096 Dec  6 05:51 pip-EHe6bt-unpack
-rw------- 1 root root  181 Dec  9 18:35 hosts
You have mail in /var/spool/mail/root

[root@node01 ~]# ansible webservers -m file -a "src=/etc/hosts dest=/tmp/hosts mode=700 owner=mqm group=mqm"
192.168.137.3 | SUCCESS => {
    "changed": true, 
    "failed": false, 
    "gid": 500, 
    "group": "mqm", 
    "mode": "0700", 
    "owner": "mqm", 
    "path": "/tmp/hosts", 
    "size": 181, 
    "state": "file", 
    "uid": 500
}

使用file模块也可以创建目录,于执行mkdir -p 效果类似:

$ ansible webservers -m file -a "dest=/tmp/tlcb mode=755 owner=mqm group=mqm state=directory"

[root@node01 ~]# ansible webservers -m file -a "dest=/tmp/tlcb mode=755 owner=mqm group=mqm state=directory"
192.168.137.3 | SUCCESS => {
    "changed": true, 
    "failed": false, 
    "gid": 500, 
    "group": "mqm", 
    "mode": "0755", 
    "owner": "mqm", 
    "path": "/tmp/tlcb", 
    "size": 4096, 
    "state": "directory", 
    "uid": 500
}


管理包:

确认一个软件包已经安装,但不去升级它:

[root@node01 ~]# ansible webservers -m yum -a "name=acme state=present"
192.168.137.3 | FAILED! => {
    "changed": false, 
    "failed": true, 
    "msg": "python2 bindings for rpm are needed for this module. python2 yum module is needed for this  module"
}

[root@node01 ~]# ansible webservers -m yum -a "name=acme state=absent"
192.168.137.3 | FAILED! => {
    "changed": false, 
    "failed": true, 
    "msg": "python2 bindings for rpm are needed for this module. python2 yum module is needed for this  module"
}
115.236.19.4 | SUCCESS => {
    "changed": false, 
    "failed": false, 
    "msg": "", 
    "rc": 0, 
    "results": [
        "acme is not installed"
    ]
}