Lecture: DevOps - Code Examples

This repository contains executable code that is meant to serve as examples for the DevOps lecture as part of the master's studies.

Example: Terraform

Requirements

• make
• openssh
• terraform
• r/w supporting DigitalOcean API token (./.credentials/do-api-token)

How to use

1. make init

   • generates an ssh key pair
   • initializes terraform within the project

2. make allocate

   • spins up a virtual machine

3. make connect

   • opens ssh connection to the virtual machine

4. make clean

   • destroys all allocated resources on DigitalOcean
   • removes all terraform files created during runtime

Example: Vagrant

Requirements

• make
• openssh
• vagrant
• VirtualBox (+ Extension Pack and Guest Additions)

How to use

1. make vm-prerequisites

   • installs depending vagrant plugins

2. make vm-allocate

   • spins up and prepares a local virtual machine

3. make vm-status

   • shows the current state of the local virtual machine

4. make vm-connect

   • opens ssh connection to the virtual machine

5. make vm-clean

   • destroys the local virtual machine
   • removes all vagrant files and logs created during runtime

Example: Ansible

Requirements

• make
• ansible v2.8.x
• per default the target host is the one provisioned in Example: Vagrant, so unless another host has been added in the inventory, it is required to allocate the local virtual machine first before applying the environment configuration with Ansible

Project structure

• ./environments/local/inventory contains all arguments for the local environment
• ./cm-ansible/roles contains the whole state definition and logic
• ./cm-ansible/playbooks

How to use

0. make vm (optional, if not already done)

   • spins up the local virtual machine

1. make local

   • applies configuration for the local environment

2. make test-local

   • executes all tests defined in the respective roles

Please note that the Makefile contains some more "sub-commands" (aka target) worth checking out regarding Ansible, like facts, vars or check.

Example: Jenkins

Requirements

Please refer to Example: Ansible

Project structure

See cm-ansible/roles/jenkins/README.md for mor information. Examples for pipelines can be found in ./cicd

How to use

0. Install Jenkins with the help of Ansible (see playbook main.yaml)

Add a node

1. Create a node via Jenkins UI: Manage Jenkins > Manage Nodes > New Node > Node name: agent_name (Ansible variable) + Permanent Agent > Launch method: Launch agent by connecting it to the master > Save

2. Obtain agent secret by selecting node from list & set agent_secret in Jenkins inventory file accordingly

3. Apply changes via Ansible