gm-operator

README

Grey Matter Operator (Proof of Concept)

Grey Matter Operator is a Kubernetes operator that watches for greymatter.io/v1.Mesh CR (Custom Resource) objects in a Kubernetes cluster and installs the core Grey Matter services into the same namespace where the Mesh CR exists. Grey Matter Operator also spawns a process that will call the Control API to configure routing for each installed core service.

Quickstart

This assumes you have at least Go 1.15, K3d, and kubectl installed.

1. Download Go dependencies: go mod vendor
2. Build the Docker image: make docker-build
3. Make a K3d cluster: make k3d
4. Import the Docker image into K3d: make k3d-import

Prior to deploying, store your Grey Matter LDAP credentials in the environment variables NEXUS_USER and NEXUS_PASSWORD. These will be used to create a secret for pulling Docker images.

To deploy:

1. Deploy to the K3d cluster: make deploy.
2. Create a Mesh CR: make sample
3. Check the Mesh CR: kubectl get mesh sample-mesh -o yaml

The mesh will then be available via localhost:30000.

To clean up:

1. make remove-sample
2. make undeploy
3. make destroy

Development

Scaffolding

Grey Matter Operator makes use of a tool called controller-gen for scaffolding the Mesh CRD (Custom Resource Definition) in code as well as the code that registers it. It is used in this project via two commands:

• make generate: Generates code used to implement a Kubernetes object. This enables Mesh CR objects to be managed entities in the Kubernetes API.
• make manifests: Generates configuration used to deploy Grey Matter Operator and the Mesh CRD into a Kubernetes cluster.

NOTE: As this project matures, make manifests should be replaced by a versioned CLI that programmatically applies all of the configurations to the Kubernetes cluster.

Important Files

• pkg/api/v1/mesh_types.go: Used to generate the Mesh CRD. Every time this is updated, run make generate and make manifests.
• manifests/crd/bases/greymatter.io_meshes.yaml: The Mesh CRD generated by make manifests.
• pkg/controllers/mesh_controller.go: Logic for what to do when a Mesh CR is created/updated (i.e. deploy and configure the mesh).
• pkg/controllers/reconciler.go: A custom interface with methods for reconciling Kubernetes resources based on configuration passed in from a Mesh CR. See the reconcilers directory for how this interface is implemented for each Kubernetes resource.
• pkg/gmcore/gmcore.go: This package defines configuration for each version of Grey Matter. At runtime, configurations will be applied starting with base.go and then continuing with either version_1_3.go or version_1_6.go as patches. base.go contains configuration that should apply to all versions, while the others allow for specifying version-specific configurations.
• pkg/meshobjects/objects.go: This package provides a client with methods for scaffolding mesh objects (i.e. Cluster, Listener, Domain, Proxy, etc.). It is based loosely on this gm-catalog internal package.

Resources

• Kubebuilder
• Controller Runtime Client API
• Operator Framework: Go Operator Tutorial
• Operator SDK Installation
• Operator Manager Overview