<strong>2. Types of Terraform variable - String </strong>
provider "aws" {
  region     = "us-west-2"
  access_key = "xxxxxxxxxxxx"
  secret_key = "xxxxxxxxxxxxxxx"
}

resource "aws_instance" "first-ec2" {
  ami           = "ami-03d5c68bab01f3496" # us-west-2
  instance_type = "t2.micro"
  
  tags = {
    Name = "anitha"
  }
}

<strong>3. Types of Terraform variable – List</strong> 
terraform {
  required_providers {
    aws = {
      source  = ""hashicorp/aws"
      version = "~> 3.0"
    }
  }
}

# Configure the AWS Provider
provider "aws" {
  region = "us-west-2"
  access_key = "xxxxxxxxxxxxx"
  secret_key = "xxxxxxxxxx"
}


variable "users" {
    type    = list
    default = ["devopsschool11", "devopsschool2", "devopsschool3"]
    description = "This is for demo of list variable"
}

resource "aws_instance" "anitha" {
  ami           = "ami-03d5c68bab01f3496"
  instance_type = "t2.micro"
  tags = {
    Name = "${var.users[0]}"
  } 
 


}

<strong>4. Types of Terraform variable – Map</strong>
provider “aws” {
region = “us-west-2”
access_key = “xxxxxxxxx”
secret_key = “xxxxxxxxxxxx”
}

resource “aws_instance” “first-ec2” {
ami = “ami-03d5c68bab01f3496” # us-west-2
instance_type = “t2.micro”

tags = {
Name = “anitha”
}
}

variable “amis” {
type = “map”
default = {
“us-east-1” = “ami-b374d5a5”
“us-west-2” = “ami-4b32be2b”
}
}

resource “aws_instance” “example” {
ami = var.amis[var.region]
instance_type = “t2.micro”
}

Terraform Ansible D

Write a terraform script where you create a linux ec2 instance with Security group and key defined so you should be able to use key to login to ec2 instance.

  
provider "aws" {

source = "terraform"{
version = "~> 2.8"
 }
}

resource provider "linux_security_group " allow key to login to ec2 instance"{

description = " allow key to login ec2 instance" 
}

region = "us-west-2" {
    access_key = "AKIAYIMEDZZZKEPKRNEM"
    secret_key = "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"

resource " aws_instance""first-ec2"{

ani = "ani-03d5c68bab01f3496" 
instance type = "t2.micro"
tags = {
   Name = "Anitha"
  }
}
}

“What is jenkins”?

Jenkins is a free and open source automation server. It helps automate the parts of software development related to building,trsting,and deploying,facilitating continuous integration and continuous delivery. It is a server-based system that runs in servlet containers such as Apache Tomcat

Advantages of Jenkins include:

• It is an open-source tool with great community support.
• It is easy to install.
• It has 1000+ plugins to ease your work. If a plugin does not exist, you can code it and share it with the community.
• It is free of cost.
• It is built with Java and hence, it is portable to all the major platforms.

Top 10 Jenkins plugins

1.Kubernetes

 The Kubernetes plugin is great for automating build agents on a Kubernetes cluster.

2.Swarm 

 It helps make life easier by allowing you to add worker nodes to a Jenkins master node effectively creating a cluster

3.Amazon elastic container service 

A plugin that deploys build agents to an existing Amazon ECS cluster. These builds run within separate Docker containers that are removed upon completion of the build.

4.Azure container service 

Azure Container Services is being deprecated by Microsoft, but this plugin still supports it as well as Azure Kubernetes Service

5.Jira

Jira is an open source plugin that does exactly what it says. Once installed, you can integrate your Jenkins instance with Atlassian Jira Software.

6.Pipeline

The “View Job Filters” plugin lets you choose from a wide range of filters to help manage lots of jobs. Basically, this lets you see only the jobs you want to see within a view.

7.Metrics 

 The Metrics plugin uses the Dropwizard Metrics API to conduct standard health checks and gather standard metrics on plugins installed on your Jenkins instance.

8.Jira

“Jira” is an open source plugin that does exactly what it says. Once installed, you can integrate your Jenkins instance with Atlassian Jira Software.

9.Git 

 The Git plugin allows jobs to connect to remote repositories and run git operations against them.

10.Scm API

Multijob” is a free plugin that is useful for cleaning up messes with chain definitions from upstream and downstream jobs

Prometheus is an open-source systems monitoring and alerting toolkit.

Time Series Database

Time series data is the sequence of data points collected at a regular intervals over a period of time (metrics). For eg:- device data, weather data, etc. The data require aggregation and analysis.

How prometheus is good for time series metrix?

Prometheus is a very good tool for processing and monitoring time series data. This versatile tool can be used with Graphana, a statistics visualization, and anomaly observation tool. This tool can collect data from highly loaded servers, various IoT devices, complex data processing systems, and many more.

What are components of prometheus?

1.Exporters : Exporters enable you to collect data from services and components that you cannot add direct instrumentation to because you do not have code access—for example, databases, OS kernels, routers, or cloud resources

2.Service discovery : Prometheus enables us to both statically configure metrics targets and to locate targets dynamically through service-discovery mechanisms.

3.Scraping : In Prometheus, scraping is the actual process of collecting metrics from endpoints. This is accomplished when Prometheus’ data retrieval worker sends a scrape request via HTTP.

4.Storage : Prometheus includes persistent storage on a local, on-disk time-series database. You can also integrate it with remote storage via remote read/write APIs.

How Prometheus works?

Prometheus scrapes metrics from instrumented jobs, either directly or via an intermediary push gateway for short-lived jobs. It stores all scraped samples locally and runs rules over this data to either aggregate and record new time series from existing data or generate alerts.

 tasks:
  - name: create group
    group:
      name: deploy
      state: present
  

2.Write a Ansible Playbook to create a user called “deploy-user” which is part of group called “deploy” and with /bin/bash shell.

 $ ansible name=deploy-user group=deploy shell=/bin/bash state=present

3.Write a Ansible Playbook to install package named “httpd” in RHEL/centos

Install Apache name=httpd

4.Write a Ansible Playbook to start and enable the service named “httpd”

 tasks:
  - name: start service
    service:
      name: httpd

      state: started

5.Write a Ansible Playbook to create a file called “index.html” in /var/www/html with some dummy html contents.

$ ansible Create a file dest=/var/www/html/index.html mode=600 state=touch

6.Write a Ansible Playbook to reboot a self machine.

 tasks:
  - name: copy a file
    copy:
      src: index.html

      dest: /var/www/html/second.html

7.Write a Ansible Playbook to reboot a self machine.

$ ansible Install git, wget packages name=git,wget state=present

8.Write a Ansible Playbook to clone git repo. thttps://github.com/scmgalaxy/ansible-role-template

$ ansible Clone the repo using url repo=https://github.com/scmgalaxy/ansible-role-template clone=yes dest=/tmp/test

Program 1 – Write a Ansible Adhoc Commands to create a group called “deployProgram

create group deploy name=deploy

2 – Write a Ansible Adhoc Commands to create a user called “deploy-user” which is part of group called “deploy” and with /bin/bash shell

create user deploy-user name=deploy-user shell=/bin/bashcreate group deploy name=deploy

Program 3 – Write a Ansible Adhoc commands install package named “httpd” in RHEL/centos.

yum install https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm

Program 4 – Write a Ansible Adhoc commands to start and enable the service named “httpd”

ansible locallhost -m yum -a”name=httpd state=present”

Program 5 – Write a Ansible commands to create a file called “index.html” in /var/www/html with some dummy html contents.

ansable localhost-m copy-a”src=index.html dest=/var/www/html/index.html”

Program 6 – Write a Ansible commands to copy a file called “second.html” in /var/www/html/second.html with some dummy html contents.

create file index.html dest=/var/www/html/index.html mode=755 state=touch owner=root

Program 7 – Write a Ansible commands to install a package called “git”, “wget”.

install git and wget name=git,wget state=present

Program 8 – Write a Ansible Adhoc commands to clone git repo. https://github.com/scmgalaxy/ansible-role-template.

lone to git repo=https://github.com/scmgalaxy/ansible-role-template clone=yes dest=/tmp/test

Program 9 – Write a Ansible commands to reboot a self machine.

reboots the machine msg=”rebooting now…”

Types Of Services In Kubernetes:

ClusterIP – This helps in restricting the service within the cluster it expose the service within the defined kubernetes cluster

NodePort – exposes a services via static port on the deployed node. A ClusterIP service ,to which NodePort service will route automatically created.This service can be accessed from outside the cluster using NodeIP:nodePort

LoadBalancer – it use cloud provides lod balancer. NodePort and ClusterIP services are created automatically to which the external load balancer will route.

ExternalName – Maps a service to a predefined externalName field 

Use Of Service named Kubernetes in default Namespace

Kubernetes service in the default namespace is used to forward the request to the Kubernetes master which is basically the API Server. So all the requests to the Kubernetes default service from the cluster will be routed to the configured Endpoint IP.

How does services work in Kubernetes?

A Service is a type of kubernetes resources that causes a proxy to be configured to forward request to set of pods. The set Pods that will receive traffic is determined by the selector, which match labels assigned to the pods when they were created.