Cloudformation Template

Question

So I am making cloud formation template main.yaml file and one other yaml file from which parameters can be taken so that I  can reuse it by just making changes in the value of another yaml file where only values are other but facing issue. Please guide accordingly.
Parameters:
  InstanceType:
    Description: EC2 instance type
    Type: String
    Default: t2.micro
    AllowedValues: [t2.micro, t2.small, t2.medium, m4.large]
  SecurityGroupId:
    Description: Security group ID for the EC2 instance
    Type: AWS::EC2::SecurityGroup::Id
  VpcId:
    Description: VPC ID
    Type: AWS::EC2::VPC::Id
  KeyName:
    Description: Name of the key pair to use for SSH access
    Type: AWS::EC2::KeyPair::KeyName
  SubnetId:
    Description: Subnet ID for the EC2 instance
    Type: AWS::EC2::Subnet::Id

Resources:
  EC2Instance:
    Type: AWS::EC2::Instance
    Properties:
      InstanceType: !Ref InstanceType
      SecurityGroupIds: [!Ref SecurityGroupId]
      KeyName: !Ref KeyName
      SubnetId: !Ref SubnetId
      ImageId: ami-0f8ca728008ff5af4 
      UserData: !Base64
        Fn::Sub: |
          #!/bin/bash
          sudo apt-get update
          sudo apt install apache2 -y
          sudo systemctl start apache2
          sudo systemctl enable apache2
Like we ave variables in terraform in params.yaml
How do I format and define these values or take user input
InstanceType: t2.micro
KeyName: devops
SecurityGroupIds: sg-02464c840862fddaf
SubnetId: subnet-0b2bbe1a860c1ec8f
KeyName: devops
VpcId: vpc-01491099ac5c6857a
Facing issue with formatting and defining paramsyaml file.Please guide.

Answer

Hi There

First, you need to store the parameters in a json file (you cant use YAML for the parameters file).  Example parameters.json file:

```
[
   {
        "ParameterKey": "InstanceType",
        "ParameterValue": "t2.micro"
    },
    {
        "ParameterKey": "SecurityGroupId",
        "ParameterValue": "sg-xxxxxxxx"
    }
]
```
Then, you deploy your CloudFormation stack using the `--parameter-overrides` option.

```
aws cloudformation deploy --template-file /path_to_template/template.yml --stack-name my-new-stack --parameter-overrides file://path_to_parameters/parameters.json
```

Reference: https://awscli.amazonaws.com/v2/documentation/api/latest/reference/cloudformation/deploy/index.html

Cloudformation Template

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