Using the CDK is it possible to get an existing CfnDBCluster to make modifications to?
I have an AWS::RDS::DBCluster in CloudFormation whose TimeoutAction I want to change (CloudFormation doesn't support it and I don't want to use the AWS cli).
CDK doesn't natively support importing existing resources for modification.
https://medium.com/#visya/how-to-import-existing-aws-resources-into-cdk-stack-f1cea491e9
This article describes using CDK to generate the template, then use the AWS Management Console to import the resource into the stack.
Here is an issue to track the support within CDK itself: https://github.com/aws/aws-cdk-rfcs/issues/52
In your case, specifically since DB Clusters support this, you could create snapshot of the database then delete it. Then reference the snapshot id when creating recreating the cluster with CDK. Obviously it would require downtime though.
https://docs.aws.amazon.com/cdk/api/latest/docs/#aws-cdk_aws-rds.DatabaseClusterFromSnapshot.html
Related
I am required to modify pre-existing resources using cdk. I understand that there are methods to call upon that allows you to import a given resource, but how can I go about modifying that resource? For example, I have an RDS that was manually created and I want to change the instance type after creation. How do I go about doing that using cdk/cloue formation?
If you'd like to 'take ownership' of a resource in AWS with CloudFormation you can follow the steps outline here. In short:
Create a CloudFormation template that only has the one RDS resource you'd like to take ownership of. Have the template match the resource as much as possible. You should use the CDK to do this, just make sure your CDK code ONLY includes those resources you want to import. That can sometimes be tricky since L2 constructs often create more than just one CloudFormation resource. Trim back the synthesized CloudFormation template as much as needed to get just the one RDS resource you want to import.
Create a new Stack using the 'import' option. It's important that the only resources in the template are resources you are trying to import and 'take ownership of'.
Run Drift Detection and correct anything that is out of sync by updating your template and then running additional Update Stack steps.
You can, of course, have the CDK generate this template. Same rules apply, though. You need to make sure you have only the RDS instance.
Please refer to this post as I go into more detail there.
Additionally, there is a command link option, cdk import which can help do this (not detailed here or in the blog, though).
Once you have the resource imported into a stack you can continue making future changes using the CDK.
I'm new to Cloud Formation. I want to update the settings of already created a lot of RDS instances using Cloud Formation. I don't have the info about either those resources were created through CF or manually. Is it possible to update such resources with CF?
I can think of another way like I can use AWS SDK (boto3) but doing it with CF is perefrable.
The only way to do this from CloudFormation (CF) is to develop your own CF custom resource. This will be a lambda function which will use AWS SDK to query the state of your RDS databases, and perform any actions you want.
Since its fully custom, you can program any logic which satisfies your requirements.
If the resources were created manually, you can also import them to CF, and then update using CF.
I'm fairly new to AWS CDK, and I just created an architecture with an Aurora cluster inside of it. Is there a way to initialize a database schema inside of my CDK files? It seems a bit annoying to create the instance and then have to connect through other means in order to set up a schema. My impression of CDK is that you can do everything relating to setting up the services, so I was curious if this is a possibility.
If this isn't possible, can I use a lambda that fires off after the CDK deployment? Or maybe have a snapshot inside of s3? I'm just trying to find the best solution!
You can do this, although it requires you to execute it as a custom resource within the CDK.
You would need to create a Lambda function the performs the SQL DDL tasks for you. This would then return a successful flag back to the execution runtime to say that this "resource" was successfully created.
I've got a big-ass Serverless project and I wonder if matching the cloud formation template schema with CDK would do the trick, or is there something extra to the process.
It is possible to deploy a CDK app to an existing CloudFormation stack, although it would be very difficult to achieve for non-trivial stacks since CDK apps usually involve many resources.
The cdk diff command will be your best friend. You can name your stack in the CDK app using the same name as the existing stack:
MyExistingStack(app, 'my-existing-stack')
Then you can iteratively add/remove resources and run cdk diff to check your success in matching the current deployment. CDK will additionally create metadata resources that will be added to the stack in addition to the currently existing resources.
Matching resource names can be difficult. CDK automatically names many of the resources in a way that will not match you existing stack. Following the instructions on CDK Escape Hatches, you can access lower level CFN Resources directly and modify the name.
If a Construct is missing a feature or you are trying to work around an issue, you can modify the CFN Resource that is encapsulated by the Construct.
All Constructs contain within them the corresponding CFN Resource. For example, the high-level Bucket construct wraps the low-level CfnBucket construct. Because the CfnBucket corresponds directly to the AWS CloudFormation resource, it exposes all features that are available through AWS CloudFormation.
The basic approach to get access to the CFN Resource class is to use construct.node.defaultChild (Python: default_child), cast it to the right type (if necessary), and modify its properties.
I´m using AWS CLI and CloudFormation, and I could not find any reference in the documentation.
Does anybody know if it´s possible to create a CloudFormation template from a current configuration.
Let´s say that I want to get a CloudFormation template from my current security group configuration.
Any idea if it´s possible to export that configuration as a template using CLI?
Based on our experience we found 3 possible ways to translate existing manually deployed (from Web Console UI) AWS infra to Cloudformation (CF).
Using a new CloudFormation native introduced feature (since Nov 2019) that allows you to Import existing resources into a CloudFormation stack
Using aws cli execute $aws service_name_here describe for each element that make up your stack eg for RDS Database Stack:
RDS Instance -> Type: AWS::RDS::DBInstance,
RDS (EC2) SG -> Type: AWS::EC2::SecurityGroup,
RDS Subnet Group -> Type: AWS::RDS::DBSubnetGroup and
RDS DB Param Group -> Type: AWS::RDS::DBParameterGroup
And manually translate to CF based on the outputs obtained from the aws cli for each of the components. This approach usually requires more experience in both AWS and CF but the templates that you are creating can be structured and designed under good practices, fully parameterized (Sub, Ref, Join, Fn::GetAtt:, Fn::ImportValue), modular, applying conditions and in a 1st iteration the result would probably be close to the final state of the templates (interesting reference examples: https://github.com/widdix/aws-cf-templates/).
Extra points! :)
Some other new alternatives to export your current deployed AWS infra to Cloudformation / Terraform code:
https://former2.com
https://modules.tf
https://www.brainboard.co/
Related Article: https://medium.com/#exequiel.barrirero/aws-export-configuration-as-code-cloudformation-terraform-b1bca8949bca
It's not possible using the AWS CLI but you can use the CloudFormer [1] tool to create a CloudFormation template from existing resources. I've had decent success with it. The templates aren't as "pretty" as hand-made templates but they provide a good starting point.
[1] http://aws.amazon.com/developertools/6460180344805680
In addition to CloudFormer, you might want to take a look at Bellerophon: https://github.com/arminhammer/bellerophon.
I had some problems getting the tradidtional tools - mentioned above - working in our environment; we have a complicated API Gateway. Former2 didnt' find it at all (although seemed ideal for other resources)
I found another tool, "Terraformer" which extracts AWS into Terraform, which can then be turned into CloudFormation -or used directly as IaC.
https://github.com/GoogleCloudPlatform/terraformer#installation
Maybe that will work for others if the above tools don't.