/transite-gateway

transite-gateway

transit-gateway

Without Transit Gateway

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With Transit Gateway

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Routing Sample:

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Here we are doing the setup of Transite gateway on same aws account across three diffrent VPC's.

Demo Setup:

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Steps:

  1. Create 3 VPC's and public and private subnets using below cloud formation tempalates.

     aws cloudformation --region us-east-2 create-stack --stack-name vpc1 --template-body file://vpc1_cfn.yaml
 aws cloudformation --region us-east-2 create-stack --stack-name vpc2 --template-body file://vpc2_cfn.yaml
 aws cloudformation --region us-east-2 create-stack --stack-name vpc3 --template-body file://vpc3_cfn.yaml

  2. Now create EC2 instance in each VPC's private subnet.

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  1. Now will create transit gateway in default VPC

Uder VPC --> Transit Gateways --> create transit gateway

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Keep all default options as it is.

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  1. Create transit gateway attachment to all 3 vpc's

Goto VPC --> TRANSIT GATEWAYS --> Transit gateway attachments --> Create transit gateway attachment

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Select private subnet.

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Follow the same process for remaining two VPC's.

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  1. Now will add Route Table entry for all 3 vpc Transit Gateway in respective VPC's private subnet route table.

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For now we have added route from VPC1 to VPC2 and in VPC2 to VPC1

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Now connect to private EC2 instance in VPC1 using session manager and try to do ssh. In the initial check I have not added route so it was giving timeout, later I added route then its started working.

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Currently we dont have route from VPC2 to VPC3 so if we try to do ssh from vpc2 to vpc3 EC2 instance we should get error.

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Now add the routes as below for all VPC's.

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