使用ansible远程执行命令
1.ansible简介
ansible的官方定义:“Ansible is Simple IT Automation”——简单的自动化IT工具。这个工具的目标:
- 自动化部署APP
- 自动化管理配置项
- 自动化的持续交付
- 自动化的(AWS)云服务管理。
其本质上就是在远程在多台服务器执行一系列命令和文件同步,和以前的介绍的使用并行ssh提高工作效率功能类似,他们都是使用ssh协议进行远程操作,但ansible比pssh功能更强大,比如支持主机列表分组、支持playbook模板文件等。本文仅仅介绍ansible的Ad-Hoc用法,即默认的command模块,直接在shell执行命令。
2.安装
ubuntu14.04直接使用apt-get
安装:
sudo apt-get install -y ansible
也可以使用pip命令安装:
sudo pip install ansible
为了支持输入远程主机用户密码,还需要安装sshpass
工具:
sudo apt-get install -y sshpass
安装完成后创建~/.hosts文件,内容如下:
[local]
ceph-0
[mon]
ceph-1
[osd]
ceph-2
ceph-3
以上配置文件定义了三个主机组,分别为local
、mon
、osd
,ceph-x
是主机名。ansible执行需要指定主机列表文件,默认为/etc/hosts
,用户也可以通过-i hosts_file
指定,我们修改默认文件为我们刚刚创建的新文件,创建~/.ansible.cfg
,增加以下内容:
[defaults]
hostfile=~/.hosts
3.使用ansible
ansible的简单语法为:
ansible <host-pattern> [-f forks] [-m module_name] [-a args]
其中host-pattern
指定主机组,比如上面的osd
、local
等,-f
指定并行数,默认为5
,-m
指定模块名,比如ping
表示探测远程主机是否可访问,command
表示执行shell
命令,copy
表示传输文件等,默认为command
,-a
是指定选项参数,不同的模块具有不同的参数,比如ping
不需要选项,command
需要指定执行的命令,copy
需要指定src
和dest
等。另外还有以上提到的-i
指定主机列表文件、-u
指定远程执行用户名等。
在所有的osd节点执行uptime
操作,远程主机必须有一样的用户名和密码,如果不指定用户名,则默认使用当前登录主机的用户名,否则如果和登录主机用户名不一样,必须通过-u username
指定远程主机:
ansible osd -a 'uptime'
输出:
ceph-3 | FAILED => SSH encountered an unknown error during the connection. We recommend you re-run the command using -vvvv, which will enable SSH debugging output to help diagnose the issue
ceph-2 | FAILED => SSH encountered an unknown error during the connection. We recommend you re-run the command using -vvvv, which will enable SSH debugging output to help diagnose the issue
命令执行失败,我们使用-vvvv
选项查看详细信息:
ansible -vvvv osd -a 'uptime'
输出:
ebug1: Trying private key: /home/fgp/.ssh/id_rsa
debug3: no such identity: /home/fgp/.ssh/id_rsa: No such file or directory
debug1: Trying private key: /home/fgp/.ssh/id_dsa
debug3: no such identity: /home/fgp/.ssh/id_dsa: No such file or directory
debug1: Trying private key: /home/fgp/.ssh/id_ecdsa
debug3: no such identity: /home/fgp/.ssh/id_ecdsa: No such file or directory
debug1: Trying private key: /home/fgp/.ssh/id_ed25519
debug3: no such identity: /home/fgp/.ssh/id_ed25519: No such file or directory
debug2: we did not send a packet, disable method
debug1: No more authentication methods to try.
Permission denied (publickey,password).
说明我们既没有**文件也没有输入用户密码,因此无法通过ssh认证,需要输入密码,使用-k
选项:
➜ ~ ansible osd -a 'uptime' -k
SSH password:
ceph-2 | success | rc=0 >>
11:01:17 up 1 day, 6 min, 5 users, load average: 0.02, 0.02, 0.05
ceph-3 | success | rc=0 >>
11:01:17 up 1 day, 6 min, 5 users, load average: 0.03, 0.03, 0.05
执行成功了,输入一次密码后,ansible会保存认证session,在session有效期内,不需要重复输入密码,即在执行了以上命令后,不需要再传递-k
参数:
➜ ~ ansible osd -a 'uptime'
ceph-2 | success | rc=0 >>
11:02:14 up 1 day, 7 min, 5 users, load average: 0.01, 0.02, 0.05
ceph-3 | success | rc=0 >>
11:02:14 up 1 day, 7 min, 5 users, load average: 0.01, 0.02, 0.05
有效期只有几分钟时间,为了避免每次输入密码,建议还是通过设置**来实现免密码登录,若本地还没有生成**文件,则先使用ssh-******
命令生成**文件:
➜ ~ ssh-****** [1/1877]
Generating public/private rsa key pair.
Enter file in which to save the key (/home/fgp/.ssh/id_rsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/fgp/.ssh/id_rsa.
Your public key has been saved in /home/fgp/.ssh/id_rsa.pub.
The key fingerprint is:
49:8b:d0:a0:29:69:c8:32:50:3d:fc:8a:0a:4e:c8:1d [email protected]
The key's randomart image is:
+--[ RSA 2048]----+
|...o. |
|+. o+o |
|*oo .o. . |
|oo E ..o o |
|o ..... S |
|oo... |
|+. |
|.. |
| |
+-----------------+
我们把~/.ssh/id_rsa.pub
文件拷贝到所有的主机,拷贝文件需要指定-m
模块名为copy
,指定所有的主机的host-pattern
为all
:
ansible all -m copy -a 'src=~/.ssh/id_rsa.pub dest=~' -k
ansible all -a 'ls' -k # 查看是否传输成功
接下来把公钥追加到~/.ssh/authorized_keys
中,我们需要执行cat ~/id_rsa.pub >> ~/.ssh/
命令,但默认的command
模块是不支持重定向和管道的,为了使用重定向和管道,我们使用shell
模块:
ansible all -m shell -a 'mkdir -p .ssh' # assure ~/.ssh exist!
ansible all -m shell -a 'cat ~/id_rsa.pub >> ~/.ssh/authorized_keys' -k
验证下是否工作,注意下面的命令没有指定-k
选项:
ansible all -m shell -a 'cat .ssh/authorized_keys'
输出:
➜ ~ ansible all -m shell -a 'cat .ssh/authorized_keys' [1/1839]
ceph-0 | success | rc=0 >>
ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQCxjl++nrmghoRVQnnJALR8Ia6eD87hdewZ9XZP9Ay3ZU1eU9F5MF0A7I7UY08kY7az7+14YJeP0T+zhEl8trc6NDV47LJnMG8ONVePokCeCvFgukUa8QpAhMWXSRSyUFA3Q4LpVmRu2nat$lSrwhu0W7uazq9OA5YxSCZRV/lb6bTsrrywBT4s9Crr5DWKUeZ1uKeUVghz0KmxH/ICWyFGE3v3OsqTMvtWM/R5m6FIgb86bd3CsM4UAP4v5I4FEx4+iqsbtvww3qOkY3Qj91AGOuYq8yNhFmQVN7VZZ9OR/8Vc0iI1wOG+vylbEJjr0/pjX$pPzPrOtW0Q6PjTKZXL [email protected]
ceph-3 | success | rc=0 >>
ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQCxjl++nrmghoRVQnnJALR8Ia6eD87hdewZ9XZP9Ay3ZU1eU9F5MF0A7I7UY08kY7az7+14YJeP0T+zhEl8trc6NDV47LJnMG8ONVePokCeCvFgukUa8QpAhMWXSRSyUFA3Q4LpVmRu2nat$lSrwhu0W7uazq9OA5YxSCZRV/lb6bTsrrywBT4s9Crr5DWKUeZ1uKeUVghz0KmxH/ICWyFGE3v3OsqTMvtWM/R5m6FIgb86bd3CsM4UAP4v5I4FEx4+iqsbtvww3qOkY3Qj91AGOuYq8yNhFmQVN7VZZ9OR/8Vc0iI1wOG+vylbEJjr0/pjX$pPzPrOtW0Q6PjTKZXL [email protected]
ceph-2 | success | rc=0 >>
ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQCxjl++nrmghoRVQnnJALR8Ia6eD87hdewZ9XZP9Ay3ZU1eU9F5MF0A7I7UY08kY7az7+14YJeP0T+zhEl8trc6NDV47LJnMG8ONVePokCeCvFgukUa8QpAhMWXSRSyUFA3Q4LpVmRu2nat$lSrwhu0W7uazq9OA5YxSCZRV/lb6bTsrrywBT4s9Crr5DWKUeZ1uKeUVghz0KmxH/ICWyFGE3v3OsqTMvtWM/R5m6FIgb86bd3CsM4UAP4v5I4FEx4+iqsbtvww3qOkY3Qj91AGOuYq8yNhFmQVN7VZZ9OR/8Vc0iI1wOG+vylbEJjr0/pjX$pPzPrOtW0Q6PjTKZXL [email protected]
ceph-1 | success | rc=0 >>
ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQCxjl++nrmghoRVQnnJALR8Ia6eD87hdewZ9XZP9Ay3ZU1eU9F5MF0A7I7UY08kY7az7+14YJeP0T+zhEl8trc6NDV47LJnMG8ONVePokCeCvFgukUa8QpAhMWXSRSyUFA3Q4LpVmRu2nat$lSrwhu0W7uazq9OA5YxSCZRV/lb6bTsrrywBT4s9Crr5DWKUeZ1uKeUVghz0KmxH/ICWyFGE3v3OsqTMvtWM/R5m6FIgb86bd3CsM4UAP4v5I4FEx4+iqsbtvww3qOkY3Qj91AGOuYq8yNhFmQVN7VZZ9OR/8Vc0iI1wOG+vylbEJjr0/pjX$pPzPrOtW0Q6PjTKZXL [email protected]
可见我们免密码执行远程命令,并且验证了公钥已经追加到~/.ssh/authorized_keys
中。
下面我们执行一下更新操作,命令为apt-get update -y
:
ansible all -m shell -a 'apt-get update -y'
输出结果:
ceph-1 | FAILED | rc=100 >>
E: Could not open lock file /var/lib/apt/lists/lock - open (13: Permission denied)
E: Unable to lock directory /var/lib/apt/lists/
E: Could not open lock file /var/lib/dpkg/lock - open (13: Permission denied)
E: Unable to lock the administration directory (/var/lib/dpkg/), are you root?
ceph-2 | FAILED | rc=100 >>
E: Could not open lock file /var/lib/apt/lists/lock - open (13: Permission denied)
E: Unable to lock directory /var/lib/apt/lists/
E: Could not open lock file /var/lib/dpkg/lock - open (13: Permission denied)
E: Unable to lock the administration directory (/var/lib/dpkg/), are you root?
ceph-3 | FAILED | rc=100 >>
E: Could not open lock file /var/lib/apt/lists/lock - open (13: Permission denied)
E: Unable to lock directory /var/lib/apt/lists/
E: Could not open lock file /var/lib/dpkg/lock - open (13: Permission denied)
E: Unable to lock the administration directory (/var/lib/dpkg/), are you root?
执行失败了,显然是由于没有root权限,需要使用sudo执行命令,需要`--sudo``选项:
ansible all --sudo -m shell -a 'apt-get update -y'
如果没有**,需要输入sudo密码,需要指定-K
选项(大写的K)。
4.总结
ansible的功能非常强大,以上只介绍了如何在命令行远程执行命令,ansible还有更强大的playbook功能,playbook通过yaml文件定义,类似puppet的模板文件,具体可以参考官方文档。