I have read the AWS doc that CDK diff Compares the specified stack and its dependencies with the deployed stacks or a local CloudFormation template, I can see that my local CFN template are generated under cdk.out folder but where is the "deployed stacks" it compares with to show me the diff? Does it actually read from cloud to get that or it also somewhere has a local copy of latest deployed CFN?

if it reads from the cloud to do the diff, does it mean if I change anything manually through aws console, then the diff will be differently each time?

Thanks

CodePudding user response：

As per command documentation cdk diff can either compare your cdk.out with the actual CloudFormation stack or with another template stored locally.

Does it actually read from cloud to get that or it also somewhere has a local copy of latest deployed CFN?

If you are running cdk diff against actual CloudFormation stack, then yes command will fetch template from the cloud (AWS CloudFormation) and compare two templates.

If you are running cdk diff against locally stored template (for example, if you did a backup of previous cdk.out result), then it won't fetch anything from the cloud and will do a local comparison only.

if it reads from the cloud to do the diff, does it mean if I change anything manually through aws console, then the diff will be differently each time?

Depends on what you mean by manual changes. If you make manual changes to the CloudFormation template, then cdk diff will see that and adjust difference accordingly. If, however, you make manual change to the actual AWS resource (ex: S3 bucket), then cdk diff won't see that because your actual CloudFormation template will not change. To find differences between CloudFormation template and actual AWS resources you can use CloudFormation drift detection feature

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