使用ansible远程管理集群

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localmonosdceph-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osdlocal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srcdest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).

说明我们既没有密钥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,建议还是通过设置密钥来实现免密码登录,若本地还没有生成密钥文件,则先使用ssh-keygen命令生成密钥文件:

➜  ~ ssh-keygen                                                                                                                                                              [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 fgp@ceph-0
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-patternall:

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 fgp@ceph-0

ceph-3 | success | rc=0 >>
ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQCxjl++nrmghoRVQnnJALR8Ia6eD87hdewZ9XZP9Ay3ZU1eU9F5MF0A7I7UY08kY7az7+14YJeP0T+zhEl8trc6NDV47LJnMG8ONVePokCeCvFgukUa8QpAhMWXSRSyUFA3Q4LpVmRu2nat$lSrwhu0W7uazq9OA5YxSCZRV/lb6bTsrrywBT4s9Crr5DWKUeZ1uKeUVghz0KmxH/ICWyFGE3v3OsqTMvtWM/R5m6FIgb86bd3CsM4UAP4v5I4FEx4+iqsbtvww3qOkY3Qj91AGOuYq8yNhFmQVN7VZZ9OR/8Vc0iI1wOG+vylbEJjr0/pjX$pPzPrOtW0Q6PjTKZXL fgp@ceph-0

ceph-2 | success | rc=0 >>
ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQCxjl++nrmghoRVQnnJALR8Ia6eD87hdewZ9XZP9Ay3ZU1eU9F5MF0A7I7UY08kY7az7+14YJeP0T+zhEl8trc6NDV47LJnMG8ONVePokCeCvFgukUa8QpAhMWXSRSyUFA3Q4LpVmRu2nat$lSrwhu0W7uazq9OA5YxSCZRV/lb6bTsrrywBT4s9Crr5DWKUeZ1uKeUVghz0KmxH/ICWyFGE3v3OsqTMvtWM/R5m6FIgb86bd3CsM4UAP4v5I4FEx4+iqsbtvww3qOkY3Qj91AGOuYq8yNhFmQVN7VZZ9OR/8Vc0iI1wOG+vylbEJjr0/pjX$pPzPrOtW0Q6PjTKZXL fgp@ceph-0

ceph-1 | success | rc=0 >>
ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQCxjl++nrmghoRVQnnJALR8Ia6eD87hdewZ9XZP9Ay3ZU1eU9F5MF0A7I7UY08kY7az7+14YJeP0T+zhEl8trc6NDV47LJnMG8ONVePokCeCvFgukUa8QpAhMWXSRSyUFA3Q4LpVmRu2nat$lSrwhu0W7uazq9OA5YxSCZRV/lb6bTsrrywBT4s9Crr5DWKUeZ1uKeUVghz0KmxH/ICWyFGE3v3OsqTMvtWM/R5m6FIgb86bd3CsM4UAP4v5I4FEx4+iqsbtvww3qOkY3Qj91AGOuYq8yNhFmQVN7VZZ9OR/8Vc0iI1wOG+vylbEJjr0/pjX$pPzPrOtW0Q6PjTKZXL fgp@ceph-0

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'

如果没有密钥,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。

posted @ 2016-04-15 12:06  int32bit  阅读(...)  评论(... 编辑 收藏