Resource Selection

Introduction to resourceSelector

It might be cases that operator need to examine resources of distinct types simultaneously.

Let's assume we would like to eliminate all Deployment instances that are not backed-up by an Autoscaler instance. The k8s-cleaner allows this action. By employing the resourceSelector, we can select all Deployment and Autoscaler instances.

As a next step, we have to define the aggregatedSelection. AggregatedSelection will be given all instances collected by the Cleaner using the resourceSelector. In this example, all Deployment and Autoscaler instances in the foo namespace.

Example - Deployment not Backed-up by Autoscaler

---
# Find all Deployments not backed up by an Autoscaler. Those are a match.
apiVersion: apps.projectsveltos.io/v1alpha1
kind: Cleaner
metadata:
  name: cleaner-sample3
spec:
  schedule: "* 0 * * *"
  action: Delete # Delete matching resources
  resourcePolicySet:
    resourceSelectors:
    - namespace: foo
      kind: Deployment
      group: "apps"
      version: v1
    - namespace: foo
      kind: HorizontalPodAutoscaler
      group: "autoscaling"
      version: v2
    aggregatedSelection: |
      function evaluate()
        local hs = {}
        hs.valid = true
        hs.message = ""

        local deployments = {}
        local autoscalers = {}
        local deploymentWithNoAutoscaler = {}

        -- Separate deployments and services from the resources
        for _, resource in ipairs(resources) do
            local kind = resource.kind
                if kind == "Deployment" then
                    table.insert(deployments, resource)
                elseif kind == "HorizontalPodAutoscaler" then
                    table.insert(autoscalers, resource)
                end
        end

        -- Check for each deployment if there is a matching HorizontalPodAutoscaler
        for _, deployment in ipairs(deployments) do
            local deploymentName = deployment.metadata.name
            local matchingAutoscaler = false

            for _, autoscaler in ipairs(autoscalers) do
                if autoscaler.spec.scaleTargetRef.name == deployment.metadata.name then
                    matchingAutoscaler = true
                    break
                end
            end

            if not matchingAutoscaler then
                table.insert(deploymentWithNoAutoscaler, {resource = deployment})
                break
            end
        end

        if #deploymentWithNoAutoscaler > 0 then
          hs.resources = deploymentWithNoAutoscaler
        end
        return hs
      end