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Use CDK8S To Create AWS Controllers for Kubernetes Custom Resources

Abstract

  • There is question, How does ACK relate to cdk8s?
  • Answer: All of the ACK controllers watch for specific CRs and you can generate those resources using cdk8s. The two projects complement each other. cdk8s can create the Kubernetes resources and ACK uses those resources to create the AWS infrastructure.
  • This post gives example of generating kubernetes manifest of ACK using cdk8s typescript

Table Of Contents


๐Ÿš€ Pre-requisite

๐Ÿš€ Init cdk8s-app projen

  • You can just init cdk8s project using cdk8s init typescript-app but following is used projen to mange configuration through code
  • Init cdk8s-app-ts with projen in typescript. ```

โšก $ projen new cdk8s-app-ts --projenrc-ts


- cdk8s import
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โšก $ cdk8s import --language typescript --output src/imports
Importing k8s v1.22.0...
Importing resources, this may take a few moments...
k8s


## ๐Ÿš€ **Import ACK CRDS As CDK8S API** <a name="Import-ACK-CRDS-As-CDK8S-API"></a>
- [s3-controller crds](https://github.com/aws-controllers-k8s/s3-controller/tree/main/helm/crds)
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โšก $ cdk8s import https://raw.githubusercontent.com/aws-controllers-k8s/s3-controller/main/helm/crds/s3.services.k8s.aws_buckets.yaml --output src/imports/
Importing resources, this may take a few moments...
s3.services.k8s.aws
s3.services.k8s.aws/bucket


- [rds-controller crds](https://github.com/aws-controllers-k8s/rds-controller/tree/main/helm/crds), rename file from `rds.services.k8s.aws.ts` to `rds.services.db.instance.k8s.aws.ts` after import due to that name is assigned for all CRDS with in the `rds-controller` crds
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โšก $ cdk8s import https://raw.githubusercontent.com/aws-controllers-k8s/rds-controller/main/helm/crds/rds.services.k8s.aws_dbinstances.yaml --output src/imports/
Importing resources, this may take a few moments...
rds.services.k8s.aws
rds.services.k8s.aws/dbinstance

โšก $ mv src/imports/rds.services.k8s.aws.ts src/imports/rds.services.db.instance.k8s.aws.ts


- RDS subnet group, rename file from `rds.services.k8s.aws.ts` to `rds.services.subnet.group.k8s.aws.ts`
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โšก $ cdk8s import https://raw.githubusercontent.com/aws-controllers-k8s/rds-controller/main/helm/crds/rds.services.k8s.aws_dbsubnetgroups.yaml --output src/imports/
Importing resources, this may take a few moments...
rds.services.k8s.aws
rds.services.k8s.aws/dbsubnetgroup

โšก $ mv src/imports/rds.services.k8s.aws.ts src/imports/rds.services.subnet.group.k8s.aws.ts


## ๐Ÿš€ **Get your hands dirty with code now** <a name="Get-your-hands-dirty-with-code-now"></a>
- [RDS](https://github.com/vumdao/aws-cdk8s-ack-cr/src/rds)
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rds
โ”œโ”€โ”€ constants.ts
โ”œโ”€โ”€ db-instance.ts
โ””โ”€โ”€ subnet-group.ts


  - DBInstance requires subnet group which contains private subnets in EKS VPC (`subnet-group.ts`) and secret keys to hold user credential. The k8s secret is not generated through code here.
  - `db-instance.ts` defines specs of `DbInstance`

- [S3](https://github.com/vumdao/aws-cdk8s-ack-cr/src/s3)
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s3
โ”œโ”€โ”€ constants.ts
โ””โ”€โ”€ s3.ts


## ๐Ÿš€ **Build manifest** <a name="Build-manifest"></a>
- Just run `yarn build`
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โšก $ yarn build
yarn run v1.22.15
warning ../../../package.json: No license field
$ npx projen build
๐Ÿ‘พ build ยป default | ts-node --project tsconfig.dev.json .projenrc.ts
๐Ÿ‘พ build ยป compile | tsc --build
๐Ÿ‘พ build ยป post-compile ยป synth | cdk8s synth
No manifests synthesized
๐Ÿ‘พ build ยป test | jest --passWithNoTests --all --updateSnapshot
No tests found, exiting with code 0
----------|---------|----------|---------|---------|-------------------
File | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s
----------|---------|----------|---------|---------|-------------------
All files | 0 | 0 | 0 | 0 |
----------|---------|----------|---------|---------|-------------------
๐Ÿ‘พ build ยป test ยป eslint | eslint --ext .ts,.tsx --fix --no-error-on-unmatched-pattern src test build-tools .projenrc.js
Done in 25.90s.


- Output directory
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dist
โ”œโ”€โ”€ rds
โ”‚ โ”œโ”€โ”€ rds-db-instance.yaml
โ”‚ โ””โ”€โ”€ rds-subnet-group.yaml
โ””โ”€โ”€ s3
โ””โ”€โ”€ s3-test-bucket.yaml


- We can now use the `yaml` files to create the AWS infrastructure through ACK

## ๐Ÿš€ **Conclusion** <a name="Conclusion"></a>
- Although we have to import ACK CRDS resources for cdk8s API, we can manage k8s manifests through code

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Top comments (1)

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ductnn profile image
Duc Tran

thank you :D