sys-engineering-automation-1

Multiple instance manipulation using Ansible

Table of contents:

• Installations
  • Ansible
  • Packer
  • Terraform
  • Summary
• Environments and Networks
  • General
    • Setup
    • SSH key generation
• Ansible
  • Configuration
  • Naming nodes
  • Commands
  • Grouping nodes

Sub-Directories

• Ansible
  • About
  • Training Sample
    • First Configuration
• Packer
  • AWS
    • Configuration
    • Execution results
  • VirtualBox
    • Configuration
      • Transferred Files
    • Execution results

Installations

First things first! let's update our repositories and see what packages we have!

apt-get update;

Step 1: Installing Ansible

Using apt

Install for all users

sudo apt-get install -y ansible;

or
Install for single user

sudo apt install -y ansible;

Using source
use this method, if above one fails

sudo apt-get install -y git;
git clone git://github.com/ansible/ansible.git && cd ./ansible;
source ./hacking/env-setup;

Note: you will have access to ansible commands only from terminal tabs/windows, that are sourcing ansible's hacking/env-setup
Check Ansible installation

if command -v ansible &> /dev/null; then echo "ansible successfully installed"; else echo "failed to install ansible"; fi

Step 2: Installing Packer

Using apt

Install for all users

sudo apt-get install -y packer
curl -fsSL https://apt.releases.hashicorp.com/gpg | sudo apt-key add -
sudo apt-add-repository "deb [arch=amd64] https://apt.releases.hashicorp.com $(lsb_release -cs) main"
sudo apt-get update && sudo apt-get install Packer

or
Install for single user

sudo apt install -y packer

Using repo
use this if above installation fails

Emergency instllation for all users*

sudo apt-get install -y curl;
curl -fsSL https://apt.releases.hashicorp.com/gpg | sudo apt-key add -;
sudo apt-add-repository "deb [arch=amd64] https://apt.releases.hashicorp.com $(lsb_release -cs) main";
sudo apt-get update && sudo apt-get install packer;

Emergency instllation for current user*

sudo apt install -y curl;
curl -fsSL https://apt.releases.hashicorp.com/gpg | sudo apt-key add -;
sudo apt-add-repository "deb [arch=amd64] https://apt.releases.hashicorp.com $(lsb_release -cs) main";
sudo apt-get update && sudo apt install packer;

Check Packer installation

if command -v packer &> /dev/null; then echo "packer successfully installed"; else echo "failed to install packer"; fi

Step 3: Installing Terraform

sudo apt-get install -y unzip;
wget https://releases.hashicorp.com/terraform/0.15.0/terraform_0.15.0_linux_amd64.zip;
unzip terraform*.zip;
sudo mv terraform /usr/local/bin;
rm terraform*.zip; 

Note: Version of Terraform might be different! look for correct version here

Check Terraform installation

if command -v terraform &> /dev/null; then echo "terraform successfully installed"; else echo "failed to install terraform"; fi

Summary

All steps from Installations are wrapped up in provision-master.sh file in current repository

Environment & Connections

General

Setup

in current state, we have few VirtualBox instances
1 Master and few Slave.
username of Slave devices should be SAME!
on slave devices, we need to install and setup openssh-server. see provision-slave.sh script.
On VirtualBox we have shared network that we created from virtual box's settings

FIle -> Host Network Manager settings Add network mode Host to all virtual box instances so they will be on same, shared network.

In my case, VirualBox's network is 192.168.56.100.
It means that each device i add, will be adding up at the end like: 192.168.56.101, 192.168.56.102, 192.168.56.103 and so on.

In this example, 192.168.56.101 is Master device when 192.168.56.102 and 192.168.56.103 are slave devices.

note: if you don't know exact ip address of your slave devices run ip a command and look for something like 192.168.***.*** where * can be any number. or look for ip address under enp0s*, where * is any number, after running ip a

Generate ssh-keys for connection

Run following command only on Master device:

ssh-keygen

and keep clicking enter on all prompts.

Copy ssh public key for passwordless connection

Run following command on Master device:

ssh-copy-id slave@192.168.56.102

Note: provide password when asked

/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed
/usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys
slave@192.168.56.102's password: 

Number of key(s) added: 1

Now try logging into the machine, with:   "ssh 'slave@192.168.56.102'"
and check to make sure that only the key(s) you wanted were added.

Important: Repeat this process (ssh-copy-id) for each slave device!

Note: for all non-master ip's that we are going to control

Ansible

Configuration

Now that everything is set up, you can go in /etc/ansible/hosts file as root and add your slave device ip addresses

note: you can use sudo nano /etc/ansible/hosts

After appending slave ip addresses, your /etc/ansible/hosts should look like this

Note: it may be different, based on where you have added ip addresses. In this case, we ate adding them at the top

192.168.56.102 
192.168.56.104 
# more ip adresses


# This is the default ansible 'hosts' file.
#
# It should live in /etc/ansible/hosts
#
#   - Comments begin with the '#' character
...

Note: remember that ip adresses can be different in your case

naming slave nodes

Again, in /etc/ansible/hosts we should change our configuration to following

slave1 ansible_ssh_host=192.168.56.102 ansible_ssh_user=slave
slave2 ansible_ssh_host=192.168.56.104 ansible_ssh_user=slave
# more configurations


# This is the default ansible 'hosts' file.
#
# It should live in /etc/ansible/hosts
#
#   - Comments begin with the '#' character
...

where slave1 and slave2 are names of nodes. you can name them anything!
ansible_ssh_host is variable that stores ip address of node as value.
ansible_ssh_user is variable that stores username of target node.

now we can execute all command by replacing all to slave-name, for example

ansible -m shell -a 'uname -a' slave1

note: you can find more modules and commands below

Commands

Make sure that you configured your configuration file correctly.
Now let's send command to all devices together!

Run following command:

ansible -u slave -m ping all

This will check if everything is configured correctly
Note: after -u tag, you can inout username of your slave devices, instead of slave.
Note: if you used additional configuration with usernames, you do not need to use -u tag

If you get green output, it means everything went Great! if you see red output, it means something went wrong for that particular device.
Make sure that device is running with sshd service and ssh ports are enabled on device.

when that command succeds, you can use other modules of ansible like:

Command: shell - Execute a command on slave devices

ansible -m shell -a 'uname -a' all

you can use command you want instead of 'uname -a', after -a argument

Command: copy - Copy file from slave devices

ansible -m copy -a 'src=/etc/motd dest=/tmp/' slave1

Comand: setup - Described information about slave device

ansible -m setup slave2

Grouping devices

Create new file wherever you want. This file will be used for additional ansible configuration.
In our case, we are creating file in /etc/ansible and naming it host-config

In /etc/ansible/host-config we should add ip adresses we want to group (in one in separate groups) and add group tag at the top

[ubuntu]
slave1 ansible_ssh_host=192.168.56.102 ansible_ssh_user=slave
slave2 ansible_ssh_host=192.168.56.104 ansible_ssh_user=slave

# [mint]
# my mint devices here

# [mygroup]
# my device configurations here


[linux]
ubuntu
# all other group names

In the configuration above, you can see that we grouped slave1 and slave2 in group ubuntu, because they are ubuntu based devices.
You can name groups whatever you want, so it could be mygroup if we wanted.
Afterwards, we added our ubuntu group in parent, linux group.

This type of configuration, gives us adventage of manipulating devices by their type, or by service they provide.
After grouping devices, we can use this names in commands like this:

ansible -i /etc/ansible/host-config -m ping linux;
ansible -i /etc/ansible/host-config -m ping ubuntu;
ansible -i /etc/ansible/host-config -m ping slave1;

Note: you would see that we added -i tag ther refferes to configuration file

Now we can use group names instead of device names.
So we can use linux to refer to all ubuntu devices or we can use ubuntu to refer all slave1 and slave2 devices.