Ansible Kickstart

Ansible Kickstart

##What's 'Ansible' ?

Ansible is configuration management tool like SaltStack, Puppet but it works through SSH, no need to install agent on managed nodes.

##Why's Ansible ?
As my point, i love ansible for:
- No need to install agent on agent nodes

##How's Ansible?
### Install Ansible on master node

#####Red Hat/CentOS/Fedora
```
rpm -Uvh http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm
yum install ansible -y
```

#####Ubuntu/Debian
```
apt-get install python-software-properties
apt-add-repository ppa:ansible/ansible
apt-get update
apt-get install ansible
```

#####Setup ansible

All nodes (server) managed throush file  `/etc/ansible/hosts`

#####My ansible lab for 2 nodes:

**OS :**| Ubuntu 14.04
---|-----
**eth0:**| 192.168.1.73
**SSH Port:**| 2246
**SSH Pass:**| Ubuntu121

**OS:**| CentOS 6.5
---|-----
**eth0:**| 192.168.1.74
**SSH Port:**| 5918
**SSH Pass:**| Centos313

File `/etc/ansible/hosts`
```
[ansibleLab]
192.168.1.73 ansible_ssh_port=2246 ansible_ssh_user=ansible ansible_ssh_pass=Ubuntu121
192.168.1.74 ansible_ssh_port=5918 ansible_ssh_user=root ansible_ssh_pass=Centos313
```

#####Check if it works
```
ansible ansibleLab -m ping
```
```
192.168.1.73 | success >> {
    "changed": false, 
    "ping": "pong"
}

192.168.1.74 | success >> {
    "changed": false, 
    "ping": "pong"
}
```

#####Get distro information
```
ansible ansibleLab -m setup -a 'filter=ansible_distribution'`
```

```
192.168.1.74 | success >> {
    "ansible_facts": {
        "ansible_distribution": "CentOS"
    }, 
    "changed": false
}

192.168.1.73 | success >> {
    "ansible_facts": {
        "ansible_distribution": "Ubuntu"
    }, 
    "changed": false
}
```

###Ansible playbook

Ansible playbook is configuration for a node (packages installed, service, cron...)

Below is a playbook install apache on managed nodes.

`vim /srv/playbook.yml`
```
---
- hosts: ansibleLab
  gather_facts: yes
  tasks:
  - name: Install apache Ubuntu
    apt: name=apache2 state=present
    when: ansible_os_family == "Debian"
    
  - name: Install apache CentOS
    yum: name=httpd state=present
    when: ansible_os_family == "RedHat"
    
  - name: Start apache2
    service: name=apache2 state=started enabled=yes
    when: ansible_os_family == "Debian"
    
  - name: Start httpd
    service: name=httpd state=started enabled=yes
    when: ansible_os_family == "RedHat"
    
```
##### Execute playbook
```
ansible-playbook /srv/playbook.yml -v
```

```
PLAY RECAP ******************************************************************** 
192.168.1.73               : ok=3    changed=1    unreachable=0    failed=0   
192.168.1.74               : ok=3    changed=2    unreachable=0    failed=0 
```
Để ý trường `failed=0` là okie. Lần lượt vào 2 host để kiểm tra bằng lệnh `netstat -nltp`

##TroubleShooting
```
192.168.5.119 | FAILED => Using a SSH password instead of a key is not possible because Host Key checking is enabled and sshpass does not support this.  Please add this host's fingerprint to your known_hosts file to manage this host.
192.168.5.149 | FAILED => Using a SSH password instead of a key is not possible because Host Key checking is enabled and sshpass does not support this.  Please add this host's fingerprint to your known_hosts file to manage this host.
```

Sửa file `/etc/ansible/ansible.cfg`
```
[defaults]
host_key_checking = False
```

Trên đây chỉ là 1 số thông tin rất cơ bản về ansible, các bạn có thể vào link http://docs.ansible.com/ tìm hiểu thêm về ansible để phát triển theo ý muốn.

#References
https://valdhaus.co/writings/ansible-post-install/