lago-tutorial

This repository contains the default files for creating Lago environment.

In this tutorial you will learn how to set up a custom virtual environment with Lago. The virtual environment will be used as an infrastructure for your application, so you can run tests in order to check the functionality of your application, without the overhead of setting up an infrastructure.

This tutorial will be “hands on”, and will take you through the process of creating, running and deploying the environment.

Lago environments are flexible and can be used for all different kinds of tasks. For keeping things simple I will focus on one scenario, although you will get the ability to create your own custom environment. We will use only the basic mandatory commands of Lago, for further reading please advise: Lago Hompage

Prerequisites:

Install Lago - follow this tutorial for more information

The scenario:

Create a Lago environment which will consist of three virtual machines that will host Jenkins infrastructure.

The VMs:

"vm0-server" - Junkins server
"vm1-slave" - Junkins slave
"vm2-slave" - Junkins slave

The network:

All the VMs will connect to the same virtual network .

Creating the working directory:

In order to create a working directory, clone the following repo:

https://github.com/gbenhaim/lago-tutorial

What is in the repository?

init.json.in – This is the file which describes the structure of our environment: the specification of the vms, networks, the path and name of the deployment scripts for each vm.
presets - This directory contains default configuration files for common enviornments.
templates-repo – This directory contains .json files which specify the template repository that should be used. (The templates repository is the place from which the base “qcow2” virtual disks will be copied from).
deployment-scripts – This directory contains the deployment scripts for each vm (in our case a script that will install the jenkins server)

Editing init.json.in

The init.json.in is where we need to describe our environment e.g vms and network, so Lago can create them for us.

//TODO: elaborate about the different features and values that can be specified within the file.

Creating The Environment

From within the repo run:

lago init --template-repo-path=templates-repo/template-repo.json lago-work-dir init.json.in

This directory /lago-work-dir will contain the files of our new Lago environment. This directory shouldn't exist before invoking lago init.

Deploy the VMs

cd into /lago-work-dir. From now on, each command that relates to the environment, should be run from within it.

Now, lets start the vms:

lago start

Or for a specific vm named "server":

lago start server

This command will run the deployment scripts (from within the vms) that were specified in the init.json.in file.

lago ovirt deploy

Jenkins will be installed on the server. OpenJDK will be installed on the slaves.

Getting the state of the environment

You cae get information about the state of the enviorment with:

lago status

You can write down to yourself the ip adresses of the server and slaves, as we will need them when configuring the server.

Interacting with the VMs

Lago allows you to connect to the vms via ssh. for exmaple, if we have a vm named "server" we will use the following:

lago shell server

If the deployment scripts run successfuly we don't have to connect to the machines.

Adding the Junkins slaves

Open your browser and enter to the Jenkins web UI. The address should be like: "put-your-server-ip-here:8080" In the UI do the following:

Go to Manage jenkins >> Manage nodes
Click on: New node
Enter a name for the new slave (you can pick whatever name you like) and mark "Dumb Slave", now hit OK
Enter "/jenkins" in "Remoote Root Directory" (This is were Jenkins will place his files in the slave)
Enter the slave's ip in "Host"
Near the "Credentials" label, click on "add"
Enter: Username = "root", Password = "123456" - this is the root password of the vms. for more information about configuring the root password with Lago, check out Lago's website
hit the "Save" button
Repeat the process for the other slave.

Your server is now configured with the new slaves.

Shutdown the environment

In order to send a shutdown signal to the machines we will use:

lago stop