VIRTUAL PRIVATE CLOUD(VPC) USING AWS

Creating a Virtual Private Cloud(VPC) using AWS

Problem statement

In AWS if you have ec2 instances  created across different availability zones of a region, there will not be connectivity across instances with in AWS network . by default we have to use public IP connect from one instance of one availability zone to another instance of another availability zone .there are couple of disadvantages with this approach

1. Traffic is routed through pubic network which is not a safe option
2. Since public internet is used there is a bandwidth cost associated
3. Slow network connection
4. Unless you use elastic IP your public IP change every time the instance is restarted 

As a solution to above mention disadvantages AWS provides virtual private network service-virtual private cloud(VPC). We can create a virtual private network and use VPC peering to bring all instances across all availability zones in same region under one network

Different services that required as part of VPC creation are :

•  VPC
•  Subnets
•    Routing table
• Internet gateway
• vpc
• Security groups
• Ec2 instance
• putty

     brief introduction about above mentioned services:

1. What is a vpc?

• VPC is a virtual private cloud which helps us to connect multiple instances or servers ate a time in region VPC is mostly used for internal communications it does not use public IP

      2. What are subnets?

• Subnets can be simply said as range of IP addresses
• /8 - 225.0.0.0
• /9 - 255.128.0.0
• /10 - 255.192.0.0
• /16 - 255.255.0.0
• /24 - 255.255.255.0      

      3. What is a routing table?

• Routing tables consists set of rules which allows network traffic from subnets or gateway is desired once

     4. What is internet gateway?

• Internet gateway is used to provide access point for routing table which allows internet and perform network address translation (NAT)
• IPv4 - it is a 32-bit number which consists less range than IPv6
• IPv6 - it is a 128-bit  and it is bigger that it can many no of IP ranges which will never end or the user doesn’t require that many

Process of creating a VPC and communication between two servers

creating a vpc(Virtual Private Cloud)

1. we need to create a VPC under network and content delivery

Mention name and IP range and enable DNS hostnames it assigns name for the server for that right click ok AWS in edit DNS hostnames enable and save 

2. Now go to subnets and create a subnet

Name as shown above and create 

Again create a another subnet to expand our VPC subnet naming as above and availability zone as (ap-southeast-1b) and IPv4 as 10.1.2.0/24

create a subnet shown above by this our VPC is expanded to 3 availability zones

For brief explanation IP ranges are

10.1.1.0/24 – 10.1.1.0 to 10.1.1.255

10.1.1.0 – network ID

10.1.1.255 – Broadcast ID

10.1.1.1,2,3 – used by AWS for gateways

Instances will run from 10.1.1.4 to 10.1.1.254

Enable auto assign for all the subnets by right click

3. Now create a internet gateway and attach to VPC

Create a gateway naming as above after that the gateway will be in the detached mode we need to attach to our VPC

Attach the created VPC 

4. Create a routing table and assign IGW and subnets to it

Routing table helps to communicate servers with IGW using routing table

Go to subnet associations and add 2 subnets in routing table and leave dbserver for communication between servers

Create another routing table for db server

Add dbserver

Go to edit Routes in routing table and route under destination as 0.0.0.0/0-which can access any IP

Do same for second routing table

5. Create a security group and allow traffic

Create a security group as shown above and edit inbound rules and allow all traffic and save rules

6. Now create a keypair

Now go to the EC2 instance and go to key pairs

Create key pair as AWS_VPC or your wish it should be in ppk 

Save the file to the desired location 

7. Deploy a Instance(VM) and access using putty

Now launch instance in EC2 and select amazon linux2 and instance type as t2.micro

Select network as created VPC and subnets as AWS-webservers and primary IP as 10.1.1.111

Under configure security group select existing security group and select AWS-allow-all and launch the instance

Select existing key pair which was created above

Above private IP is used for internal communication and public IP is used by the user

Now open putty

Copy this and past in putty as ec2-user@ ec2-13-250-97-44.ap-southeast-1.compute.amazonAWS.com

Go to Auth under SSH and place your security key and click on open 

Now your connected to your ec2 instance

Now type as sudo su – it will go to root access 

Now create a another instance and add dbserver in configuration 

We are trying to communicate between server1 and server2

Now follow the same steps involved in putty for server 1

It shows same for server2 as shown in the server1

Now ping server1 from server2 using IPaddress of server1

Use command as ping and IP address of server1 that is 10.1.1.111 so that we can see the servers are communicating with each other

Now do the same process but it should be from server1 to server 2

By this process we know that servers are communicate with each other from one availability zone to another one in the same region