How to work with Ansible (Automation tool) on CentOS 7
Ansible is free tool to automation tool for Linux hosts. Its useful for the environment where you have lots of linux hosts/servers to manage and maintain. Lets get started with it,
I have tested the below mentioned steps on CentOS 7:
First of all, we are going to need epel on CentOS to install ansible:
[root@vm2 ~]# uname -r
3.10.0-123.el7.x86_64
[root@vm2 ~]# cat /etc/redhat-release
CentOS Linux release 7.0.1406 (Core)
[root@vm2 ~]# yum install epel-release
Now after installing epel, lets install ansible:
[root@vm2 ~]# yum install ansible
After installation is done, test it out:
[root@vm2 ~]# ansible --version
ansible 2.0.2.0
config file = /etc/ansible/ansible.cfg
configured module search path = Default w/o overrides
Now, ansible works on ssh keys. So just generate one if you don't have it.
[root@vm2 ~]# ssh-keygen
<You can have a secure password, or just keep it blank also should work>
Your identification has been saved in /root/.ssh/id_rsa.
Your public key has been saved in /root/.ssh/id_rsa.pub.
Now Copy the ssh key to remote hosts:
[root@vm2 ~]# ssh-copy-id 192.168.0.81
[root@vm2 ~]# ssh-copy-id 192.168.1.222
Now Add your hosts/servers in the below mentioned ansible file:
[root@vm2 ~]# vim /etc/ansible/hosts
[servers]
192.168.0.81
192.168.1.222
Now, Save & Exit.
Its time to test ansible with ping module:
[root@vm2 ~]# ansible -m ping 'servers'
192.168.0.81 | SUCCESS => {
"changed": false,
"ping": "pong"
}
192.168.1.222 | SUCCESS => {
"changed": false,
"ping": "pong"
}
Looks good.
Lets try some other command:
[root@vm2 ~]# ansible -m command -a 'rpm -qa kernel' 'servers'
192.168.0.81 | SUCCESS | rc=0 >>
kernel-3.10.0-327.18.2.el7.x86_64
kernel-3.10.0-327.10.1.el7.x86_64
kernel-3.10.0-327.el7.x86_64
kernel-3.10.0-327.13.1.el7.x86_64
192.168.1.222 | SUCCESS | rc=0 >>
kernel-2.6.32-504.el6.x86_64
kernel-2.6.32-573.7.1.el6.x86_64
Yeah, So Now you are able to fetch these information in single command.
[root@vm2 ~]# ansible -m command -a 'grep CPU /proc/cpuinfo' 'test-servers'
192.168.0.81 | SUCCESS | rc=0 >>
model name : Intel(R) Core(TM) i3-4130 CPU @ 3.40GHz
model name : Intel(R) Core(TM) i3-4130 CPU @ 3.40GHz
model name : Intel(R) Core(TM) i3-4130 CPU @ 3.40GHz
model name : Intel(R) Core(TM) i3-4130 CPU @ 3.40GHz
192.168.1.222 | SUCCESS | rc=0 >>
model name : Intel(R) Core(TM) i3-3240 CPU @ 3.40GHz
model name : Intel(R) Core(TM) i3-3240 CPU @ 3.40GHz
model name : Intel(R) Core(TM) i3-3240 CPU @ 3.40GHz
model name : Intel(R) Core(TM) i3-3240 CPU @ 3.40GHz
[root@vm2 ~]# ansible -m command -a 'free -m' 'test-servers'
192.168.1.222 | SUCCESS | rc=0 >>
total used free shared buffers cached
Mem: 7693 5845 1847 187 7 449
-/+ buffers/cache: 5388 2304
Swap: 7999 684 7315
192.168.0.81 | SUCCESS | rc=0 >>
total used free shared buff/cache available
Mem: 11726 6426 390 393 4909 4568
Swap: 16383 130 16253
[root@vm2 ~]# ansible -m command -a 'fdisk -l /dev/sda' 'test-servers'
192.168.0.81 | SUCCESS | rc=0 >>
Disk /dev/sda: 500.1 GB, 500107862016 bytes, 976773168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x0000f988
Device Boot Start End Blocks Id System
/dev/sda1 * 2048 1230847 614400 83 Linux
/dev/sda2 1230848 525518847 262144000 83 Linux
/dev/sda3 525518848 559073279 16777216 82 Linux swap / Solaris
/dev/sda4 559073280 976773167 208849944 5 Extended
/dev/sda5 559075328 976773167 208848920 83 Linux
192.168.1.222 | SUCCESS | rc=0 >>
Disk /dev/sda: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xa34fa34f
Device Boot Start End Blocks Id System
/dev/sda1 * 1 32 256000 83 Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2 32 7681 61440000 83 Linux
/dev/sda3 7681 8701 8192000 82 Linux swap / Solaris
/dev/sda4 8701 60802 418497560 5 Extended
/dev/sda5 8701 60802 418496512 83 Linux
Awesome. You can Also Create/Delete user accounts:
[root@vm2 ~]# ansible -m command -a "useradd spiderman" 'test-servers'
192.168.1.222 | SUCCESS | rc=0 >>
192.168.0.81 | SUCCESS | rc=0 >>
[root@vm2 ~]# ansible -m command -a "grep spiderman /etc/passwd " 'test-servers'
192.168.0.81 | SUCCESS | rc=0 >>
spiderman:x:1002:1002::/home/spiderman:/bin/bash
192.168.1.222 | SUCCESS | rc=0 >>
spiderman:x:505:506::/home/spiderman:/bin/bash
[root@vm2 ~]# ansible -m command -a "userdel -r spiderman" 'test-servers'
192.168.0.81 | SUCCESS | rc=0 >>
192.168.1.222 | SUCCESS | rc=0 >>
Hope this helped you.
Thanks ^_^
