function-describe-nodegroups

A Crossplane Composition Function which reads EKS nodegroup information and uses that to create MachinePool anbd AWSManagedMachinePool objects.

In order to use this function as part of the Composition, the composition must be written to use pipeline mode. See the documentation on Composition functions to better understand how this is integrated

Composition integration

This function is placed in the pipeline with a reference to the cluster object for that composition.

This should be specified in your composition as follows, setting clusterRef as appropriate for your composition.

    - step: describe-nodegroups
      functionRef:
        name: function-describe-nodegroups
      input:
        apiVersion: describenodegroups.fn.giantswarm.io
        kind: Nodegroups
        metadata:
          namespace: crossplane
        spec:
          clusterRef: eks-cluster

How it works

AWS provider

This function performs a lookup against the AWS API for Nodegroups linked to the clustername referenced in clusterRef. It then iterates over that information and populates additional information from secondary lookups to the EC2 API and Autoscaling API as appropriate.

Once all information is retrieved, this is then populated into a cluster-api provider-aws AwsManagedMachinePool object, wrapped inside a crossplane-contrib/provider-kubernetes object and returned as a desired resource to be reconciled and created by crossplane.

If the nodegroup was created with a LaunchTemplate then the function will attempt to use that to build the specification for Cluster API. If no launch template is found then the function tries to provide all required information to Cluster Api so that it can formulate the nodepool(s).

To better understand what the function is doing, the following callgraph highlights the general flow the function follows to obtain the relevant information for building the CAPI objects.

Azure provider

TBD

GCP Provider

TBD

Building

# Run code generation - see input/generate.go
$ go generate ./...

# Lint the code
$ docker run --rm -v $(pwd):/app -v ~/.cache/golangci-lint/v1.54.2:/root/.cache -w /app golangci/golangci-lint:v1.54.2 golangci-lint run

# testing
$ go test ./... -coverprofile=cover.out && go tool cover -html=cover.out
?       github.com/giantswarm/crossplane-fn-describe-nodegroups/pkg/composite/v1beta1   [no test files]
?       github.com/giantswarm/crossplane-fn-describe-nodegroups/pkg/input/v1beta1       [no test files]
ok      github.com/giantswarm/crossplane-fn-describe-nodegroups 0.028s  coverage: 74.9% of statements

$ docker buildx build .

giantswarm/crossplane-fn-describe-nodegroups