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Catalog / DevOps Deployment Tools Cheatsheet

DevOps Deployment Tools Cheatsheet

A comprehensive cheat sheet covering essential DevOps and Cloud deployment tools, their functionalities, and usage, with practical examples.

Ansible

Core Concepts

Ansible: An open-source automation tool used for configuration management, application deployment, task automation, and IT orchestration.

Playbooks: YAML files that define the tasks to be executed on managed nodes.

Inventory: A list of managed nodes (hosts) that Ansible manages, typically defined in a file.

Modules: Reusable, standalone scripts that Ansible uses to perform tasks on managed nodes.

Roles: A way to organize and reuse Ansible playbooks. Roles group together related tasks, variables, and handlers.

Common Commands

ansible --version

Check the Ansible version.

ansible all -m ping -i inventory

Ping all hosts in the inventory file.

ansible-playbook playbook.yml -i inventory

Run an Ansible playbook against the inventory.

ansible-galaxy install role_name

Install a role from Ansible Galaxy.

ansible-vault encrypt file.yml

Encrypt a file using Ansible Vault.

Example Playbook 

--- 
- hosts: webservers
  become: true
  tasks:
    - name: Ensure Apache is installed
      apt: 
        name: apache2
        state: present
    - name: Ensure Apache is running
      service:
        name: apache2
        state: started

Terraform

Key Concepts

Terraform: An infrastructure as code (IaC) tool that enables you to define and provision infrastructure using a declarative configuration language.

Providers: Plugins that allow Terraform to interact with different infrastructure platforms (e.g., AWS, Azure, GCP).

Resources: Components of your infrastructure, such as virtual machines, networks, and databases.

Modules: Reusable and composable units of Terraform configuration, similar to functions in programming.

State: Terraform uses a state file to track the current configuration of your infrastructure.

Common Commands

terraform init

Initialize a Terraform working directory.

terraform plan

Show changes required by the current configuration.

terraform apply

Apply the changes to the infrastructure.

terraform destroy

Destroy the infrastructure managed by Terraform.

terraform show

Inspect the current Terraform state.

Example Configuration 

terraform {
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 4.0"
    }
  }
}

provider "aws" {
  region = "us-west-2"
}

resource "aws_instance" "example" {
  ami           = "ami-0c55b9479a3c8c88c" # Example AMI
  instance_type = "t2.micro"

  tags = {
    Name = "ExampleInstance"
  }
}

Kubernetes Deployments

Core Components

Deployment: Manages the desired state of your application by ensuring the specified number of replicas are running.

Pod: The smallest deployable unit in Kubernetes, representing a single instance of a running process.

Service: An abstraction that defines a logical set of Pods and a policy by which to access them.

Namespace: A way to divide cluster resources between multiple users or teams.

Ingress: Manages external access to the services in a cluster, typically via HTTP.

Common kubectl Commands

kubectl apply -f deployment.yaml

Apply a configuration file to create or update resources.

kubectl get deployments

List all deployments in the current namespace.

kubectl describe deployment <deployment-name>

Show detailed information about a deployment.

kubectl scale deployment <deployment-name> --replicas=<number>

Scale the number of replicas in a deployment.

kubectl delete deployment <deployment-name>

Delete a deployment.

Example Deployment YAML 

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
spec:
  replicas: 3
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.14.2
        ports:
        - containerPort: 80

Jenkins

Key Features

Jenkins: An open-source automation server. It helps automate the parts of software development related to building, testing, and deploying, facilitating continuous integration and continuous delivery.

Pipelines: Jenkins pipelines allow you to define your entire build, test, and deployment process as code.

Plugins: Jenkins has a wide variety of plugins available to extend its functionality, such as integrations with source control systems, build tools, and deployment platforms.

Jobs: Automated tasks or series of tasks defined within Jenkins to perform specific actions such as building or deploying applications.

Nodes/Agents: Machines or containers that Jenkins uses to execute build jobs.

Pipeline Syntax

pipeline { ... }

Defines the overall pipeline structure.

agent { ... }

Specifies where the pipeline will execute (e.g., any node, a specific label).

stages { ... }

Defines the different stages of the pipeline.

steps { ... }

Contains the actual commands to execute in each stage.

post { ... }

Defines actions to be performed after the pipeline, regardless of the outcome.

Example Jenkinsfile 

pipeline {
    agent any
    stages {
        stage('Build') {
            steps {
                echo 'Building...'
            }
        }
        stage('Test') {
            steps {
                echo 'Testing...'
            }
        }
        stage('Deploy') {
            steps {
                echo 'Deploying...'
            }
        }
    }
}
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