notes.txt

Identation is important while writing in yml file
subnet calculation: http://www.davidc.net/sites/default/subnets/subnets.html?network=10.0.0.0&mask=19&division=1.0

[] !Join ['', [!Ref "AWS::StackName", "-VPC" ]]
!Join: glueing text strings.
first '' identifies words to be glued.
!Ref: references something defined somewhere in template
AWS::StackName: stack name. todo: importance??
-VPC: suffix name for vpc. SO it will start something with "stackname-VPC"

[] !Select [ 0, !GetAZs]
!GetAZs: returns list of all the AZ in current regions.
!Select: selects specified index from the specified list. 0 is the first AZ in the list

[] !Sub ${AWS::StackName}-Public-A
!Sub: substitute function. renders and substitute values within ${} as specified.

[] DependsOn: AttachGateway todo: ??

[] AllocationId: !GetAtt ElasticIPAddress.AllocationId
AllocationId:  Allocating Fixed IP address... i.e. and elastic IP. Which remains constant irrespective
!GetAtt: get that elastic IP


CLI:
> aws cloudformation create-stack --stack-name <name>> --template-body file://./<filename>.yml --profile <>
> aws cloudformation wait stack-create-complete --stack-name <> todo:??
> aws cloudformation update-stack --stack-name <name> --template-body file://<name>>.yml
To update stack
> aws cloudformation wait stack-update-complete --stack-name <name>
To monitor progress
> aws cloudformation delete-stack --stack-name <name>
To delete

#gotchas
- any errors encountered while creating stack, entire resource creation will be rolled back.