sudo apt-get install htop

#yaml 
- name: Install htop
  apt: name=htop

#adhoc command
anisble host -m apt -a "name=htop state=present"

35.178.45.231  ansible_ssh_user=ubuntu

mkdir Ansible
cd Ansible
vagrant init

code vagrantfile

config.vm.box = "base"

change it to:

# config.vm.box = "base"

Scroll down to the last line of vagrantfile and add following configuration codes just above   end :-

----

#   apt-get install -y apache2
# SHELL
# ---- new code ---
# Some time it will take long time to download and execute configuration code. Following line is for 
# increase boot timeout value from default 300 mseconds to 12000 msecond
 
config.vm.boot_timeout=12000
# add new hosts, vagrant boxes and give ip to machines
config.vm.define "ubuntu" do |ubuntu|
  ubuntu.vm.hostname="ubuntu"
  ubuntu.vm.box="bento/ubuntu-17.10"
  ubuntu.vm.network "private_network", ip:"192.168.33.10"
end
config.vm.define "centos" do |centos|
  centos.vm.hostname="centos"
  centos.vm.box="bento/centos-7.4"
  centos.vm.network "private_network", ip:"192.168.33.20"
end
config.vm.define "server1" do |server1|
  server1.vm.hostname="server1"
  server1.vm.box="bento/ubuntu-17.10"
  server1.vm.network "private_network", ip:"192.168.33.30"
end
config.vm.define "server2" do |server2|
  server2.vm.hostname="server2"
  server2.vm.box="bento/centos-7.4"
  server2.vm.network "private_network", ip:"192.168.33.40"
end
# end of new code

end

Save the changes into vagrantfile and run the vargrant machines

vagrant up

It may take little long time to download and deploy all four machines. After successfully execute the vagrant up with have to check whether all four machines running or not.

vagrant status

Output:-

Current machine states:

ubuntu                    running (virtualbox)
centos                    running (virtualbox)
server1                   running (virtualbox)
server2                   running (virtualbox)

This environment represents multiple VMs. The VMs are all listed
above with their current state. For more information about a specific
VM, run `vagrant status NAME`.

We can see that  all four machines are running without error.

Step 3:

In this step we will access the ubuntu and centos hosts using  vasgrant ssh command and install Ansible into them. First ubuntu host:-

vagrant@ubuntu:~$ sudo apt-get update

vagrant@ubuntu:~$ sudo apt-get install software-properties-common

vagrant@ubuntu:~$ sudo apt-add-repository ppa:ansible/ansible

vagrant@ubuntu:~$ sudo apt-get update

vagrant@ubuntu:~$ sudo apt-get install ansible

Now  logout  from ubuntu and access to centos host:-

vagrant@centos:~$ vagrant ssh centos

---------------------

vagrant@centos:~$ sudo yum -y install epel-release
vagrant@centos:~$ sudo yum -y install ansible

Ansible has installed in both ubuntu and centos hosts. this machine are now controller hosts. Using Ansible we will install or configure others machines from the controller hosts.

Step 4:

At this moment we are now in centos host. I this step we will configure default host file and generate a ssh key so that we can securely access to the other machines of the network.

At first configure the Ansible default host file:-

vagrant@centos:~$ sudo vim /etc/ansible/hosts

Go to end line of hosts file and add following hosts ip on it:-

## server1 ip
192.168.33.30
## server2 ip
192.168.33.40

Now generate ssh-keys (public/private) using following command:-

ssh-keygen

While execution of above command they asked for a passphrase, you can give one for leave it empty. I left it empty here:-

Generating public/private rsa key pair.
Enter file in which to save the key (/home/vagrant/.ssh/id_rsa): 
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in /home/vagrant/.ssh/id_rsa.
Your public key has been saved in /home/vagrant/.ssh/id_rsa.pub.
The key fingerprint is:
SHA256:BpZj9IP/Q0wfKs+8EbZKdCj4nl3Z0iA+3GEZ4MGNZbA vagrant@ubuntu
The key's randomart image is:
+---[RSA 2048]----+
|      ..+=o      |
|     . =o=.      |
|      B E o .    |
|     + + = = .   |
|    . . S % .    |
|     . * & O     |
|      . = & o    |
|     . + + =     |
|      o o .      |
+----[SHA256]-----+

We have to copy the ssh keys to target machines, other wise we are unable to access them.

copy the ssh key to server1:-

vagrant@centos:~$ ssh-copy-id 192.168.33.30

server1 will asked for password. The password is  vagrant . Hit enter and following out put will show if ssh key copied successfully:-

Number of key(s) added: 1

Now try logging into the machine, with:   "ssh '192.168.33.30'"
and check to make sure that only the key(s) you wanted were added.

copy the ssh key to server2:-

vagrant@centos:~$ ssh-copy-id 192.168.33.40

server2 will asked for password. The password is  vagrant . Hit enter and following out put will show if ssh key copied successfully:-

Number of key(s) added: 1

Now try logging into the machine, with:   "ssh '192.168.33.40'"
and check to make sure that only the key(s) you wanted were added.

Now both server1 and server2 are ready for access. we can access the servers using following command:-

vagrant@centos:~$ ssh 192.168.33.30
Welcome to Ubuntu 17.10 (GNU/Linux 4.13.0-21-generic x86_64)

 * Documentation:  https://help.ubuntu.com
 * Management:     https://landscape.canonical.com
 * Support:        https://ubuntu.com/advantage

 * Ubuntu's Kubernetes 1.14 distributions can bypass Docker and use containerd
   directly, see https://bit.ly/ubuntu-containerd or try it now with

     snap install microk8s --classic

41 packages can be updated.
27 updates are security updates.


Last login: Sun May  5 04:40:54 2019 from 192.168.33.20
vagrant@server1:~$ logout

vagrant@centos:~$ ssh 192.168.33.40
Last login: Sun May  5 04:40:54 2019 from 192.168.33.20
[vagrant@server2 ~]$ logout

Step 5:

Here we will see few Ansible command for software installation and configuration. Earlier of this article I told you that in this tutorial I only show Ansible command line  configuration not play-book implementation.

Command for checking all hosts status:-

Include both server1 and server2 under a host group named servers:-

sudo vim /etc/ansible/hosts

# Group name servers
[servers]
## server1 ip
192.168.33.30
## server2 ip
192.168.33.40

vagrant@centos:~$ ansible servers -m ping
192.168.33.30 | SUCCESS => {
    "changed": false, 
    "ping": "pong"
}
192.168.33.40 | SUCCESS => {
    "changed": false, 
    "ping": "pong"
}

Here both servers ping using one Ansible command. Boths servers are ping and returned pong. That mean they are running ok.

Using -a argument:-

ansible servers -a "df -h"

From output we can see the disk and file system informations:-

92.168.33.30 | SUCCESS | rc=0 >>
Filesystem                    Size  Used Avail Use% Mounted on
udev                          479M     0  479M   0% /dev
tmpfs                          99M  7.4M   92M   8% /run
/dev/mapper/vagrant--vg-root   62G  1.4G   58G   3% /
tmpfs                         495M     0  495M   0% /dev/shm
tmpfs                         5.0M     0  5.0M   0% /run/lock
tmpfs                         495M     0  495M   0% /sys/fs/cgroup
vagrant                       234G  216G   18G  93% /vagrant
tmpfs                          99M     0   99M   0% /run/user/1000

192.168.33.40 | SUCCESS | rc=0 >>
Filesystem               Size  Used Avail Use% Mounted on
/dev/mapper/centos-root   41G  1.1G   40G   3% /
devtmpfs                 486M     0  486M   0% /dev
tmpfs                    497M     0  497M   0% /dev/shm
tmpfs                    497M  6.6M  490M   2% /run
tmpfs                    497M     0  497M   0% /sys/fs/cgroup
/dev/sda1               1014M  153M  862M  16% /boot
/dev/mapper/centos-home   20G   33M   20G   1% /home
vagrant                  234G  216G   18G  93% /vagrant
tmpfs                    100M     0  100M   0% /run/user/1000

seeing servers date time:-

vagrant@centos:~$ ansible servers -a "date"
192.168.33.30 | SUCCESS | rc=0 >>
Mon May  6 10:32:54 UTC 2019

192.168.33.40 | SUCCESS | rc=0 >>
Mon May  6 10:32:55 UTC 2019

Installing software packages on both servers:-

Since Centos and Ubuntu use different package manager, in this case we have to  execute Ansible command individually in each servers.

For server1-UbuntuOS- apt package manager:-

vagrant@centos:~$ ansible 192.168.33.30 -b -m apt -a "name=vim state=present"

output:

192.168.33.30 | SUCCESS => {
    "cache_update_time": 1557031056, 
    "cache_updated": true, 
    "changed": true
}

 

For server2-CentOS- yum package manager:-

 ansible 192.168.33.40 -b -m yum -a "name=vim state=present"

Output:

192.168.33.40 | SUCCESS => {
    "changed": true, 
    "msg": "", 
    "rc": 0, 
    "results": [
        "2:vim-enhanced-7.4.160-5.el7.x86_64 providing vim installed"
    ]
}

So that all for today. I hope this tutorial will help you to understand the Ansible concepts in a practical approach. In future I’ll write on more Ansible concept like yaml, Ansible-playbook, Roles, provision of different architectures using Ansible, collaboration of Ansible with other DevOps tools and so on. Stay Tuned in www.99coding.club. Bye till then.