View source for Ansible: Setup and Install ansible on Centos 7

== Basic Setup == 
** 4 Nodes on vScaler each with Centos 7 image (1 system with floating IP access / all nodes on internal private network)
** SSH keys setup between hosts for both users: centos/root
** SSH in to all nodes to prevent prompt about host authticity
** /etc/hosts setup on all nodes

== Install and Configure Ansible ==
* Install ansible on the server (not needed on clients) 
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# Install the RPMs
yum -y install epel-release 
yum -y install ansible 
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* Setup hosts for ansible
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# in the file: /etc/ansible/hosts
# this assumes all servers are part of the same group: servers
[servers]
#at1 ansible_ssh_host=192.168.1.27 (this is our server and does not need to be in there) 
at2 ansible_ssh_host=192.168.1.28
at3 ansible_ssh_host=192.168.1.30
at4 ansible_ssh_host=192.168.1.29
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* Check and make sure ansible can talk to all the hosts
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[root@ansible-test-1 ~]# ansible -m ping all 
at2 | SUCCESS => {
    "changed": false, 
    "ping": "pong"
}
at4 | SUCCESS => {
    "changed": false, 
    "ping": "pong"
}
at3 | SUCCESS => {
    "changed": false, 
    "ping": "pong"
}
</syntaxhighlight>

* Some examples of ansible commands
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# Ping a group of hosts
[root@ansible-test-1 ~]# ansible -m ping servers
at3 | SUCCESS => {
    "changed": false, 
    "ping": "pong"
}
at2 | SUCCESS => {
    "changed": false, 
    "ping": "pong"
}
at4 | SUCCESS => {
    "changed": false, 
    "ping": "pong"
}

# ping a single host
[root@ansible-test-1 ~]# ansible -m ping at2
at2 | SUCCESS => {
    "changed": false, 
    "ping": "pong"
}

# Ping a range of hosts
[root@ansible-test-1 ~]# ansible -m ping at2:at4
at2 | SUCCESS => {
    "changed": false, 
    "ping": "pong"
}
at4 | SUCCESS => {
    "changed": false, 
    "ping": "pong"
}

# Run a shell command on a node
[root@ansible-test-1 ~]# ansible -m shell -a 'free -m' at2
at2 | SUCCESS | rc=0 >>
              total        used        free      shared  buff/cache   available
Mem:           3791          95        3428          16         266        3478
Swap:             0           0           0

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