问题
The blog post Query for the latest Amazon Linux AMI IDs using AWS Systems Manager Parameter Store | AWS Compute Blog describes how to always reference the latest version of an distribution in a CloudFormation template.
# Use public Systems Manager Parameter
Parameters:
LatestAmiId:
Type: 'AWS::SSM::Parameter::Value<AWS::EC2::Image::Id>'
Default: '/aws/service/ami-amazon-linux-latest/amzn2-ami-hvm-x86_64-gp2'
Resources:
Instance:
Type: 'AWS::EC2::Instance'
Properties:
ImageId: !Ref LatestAmiId
How would that work for other distributions like RedHat and CentOS? What would be the parameter store path to use?
回答1:
As @John Rotenstein said, SSM seems to only have Amazon Linux AMIs. But you can still get others with DescribeImages. You can then create a custom resource to query it for you and use the result as the AMI value.
Resources:
DescribeImagesRole:
Type: AWS::IAM::Role
Properties:
AssumeRolePolicyDocument:
Version: '2012-10-17'
Statement:
- Action: sts:AssumeRole
Effect: Allow
Principal:
Service: lambda.amazonaws.com
ManagedPolicyArns:
- arn:aws:iam::aws:policy/service-role/AWSLambdaBasicExecutionRole
Policies:
- PolicyName: DescribeImages
PolicyDocument:
Version: '2012-10-17'
Statement:
- Action: ec2:DescribeImages
Effect: Allow
Resource: "*"
GetLatestAMI:
Type: AWS::Lambda::Function
Properties:
Runtime: python3.6
Handler: index.handler
Role: !Sub ${DescribeImagesRole.Arn}
Timeout: 60
Code:
ZipFile: |
import boto3
import cfnresponse
import json
import traceback
def handler(event, context):
try:
response = boto3.client('ec2').describe_images(
Owners=[event['ResourceProperties']['Owner']],
Filters=[
{'Name': 'name', 'Values': [event['ResourceProperties']['Name']]},
{'Name': 'architecture', 'Values': [event['ResourceProperties']['Architecture']]},
{'Name': 'root-device-type', 'Values': ['ebs']},
],
)
amis = sorted(response['Images'],
key=lambda x: x['CreationDate'],
reverse=True)
id = amis[0]['ImageId']
cfnresponse.send(event, context, cfnresponse.SUCCESS, {}, id)
except:
traceback.print_last()
cfnresponse.send(event, context, cfnresponse.FAIL, {}, "ok")
CentOSAmi:
Type: Custom::FindAMI
Properties:
ServiceToken: !Sub ${GetLatestAMI.Arn}
Owner: "679593333241"
Name: "CentOS Linux 7 x86_64 HVM EBS *"
Architecture: "x86_64"
You would update the values in CentOSAmi
so you can find the right AMI and then use the output with:
ImageId: !Ref CentOSAmi
回答2:
Those parameter store AMI values appear to be hand-managed by AWS. I've only found references to:
- Amazon Linux
- Windows
- ECS
来源:https://stackoverflow.com/questions/55479945/cloudformation-always-use-latest-ami