Example - ConfigMap

Introduction

There are many Kubernetes installations either as a manifest or a Helm chart that after undeployment leave ConfigMap behind.

The below Cleaner instance finds all the ConfigMaps instances in all the namespaces which are orphaned (namespaces starting with kube are excluded)

Orphaned ConfigMap

By orphaned we refer to a ConfigMap that is not used by:

• Pod through volumes (pod.spec.volumes)
• Pod through environment variables (pod.spec.containers.env and pod.spec.containers.envFrom)

Example - Cleaner Instance

---
apiVersion: apps.projectsveltos.io/v1alpha1
kind: Cleaner
metadata:
  name: unused-configmaps
spec:
  schedule: "* 0 * * *"
  action: Delete
  resourcePolicySet:
    resourceSelectors:
    - kind: Pod
      group: ""
      version: v1
    - kind: ConfigMap
      group: ""
      version: v1   
    aggregatedSelection: |
      function skipNamespace(namespace)
        return string.match(namespace, '^kube')
      end

      function getKey(namespace, name)
        return namespace .. ":" .. name
      end 

      function configMapsUsedByPods(pods)
        local podConfigMaps = {}

        for _, pod in ipairs(pods) do
          if pod.spec.containers ~= nil then
            for _, container in ipairs(pod.spec.containers) do

              if container.env ~= nil then
                for _, env in ipairs(container.env) do
                  if env.valueFrom ~= nil and env.valueFrom.configMapKeyRef ~= nil then
                    key = getKey(pod.metadata.namespace, env.valueFrom.configMapKeyRef.name)
                    podConfigMaps[key] = true
                  end
                end
              end

              if container.envFrom ~= nil then
                for _, envFrom in ipairs(container.envFrom) do
                  if envFrom.configMapRef ~= nil then
                    key = getKey(pod.metadata.namespace, envFrom.configMapRef.name)
                    podConfigMaps[key] = true
                  end
                end
              end  
            end
          end

          if pod.spec.initContainers ~= nil then
            for _, initContainer in ipairs(pod.spec.initContainers) do

              if initContainer.env ~= nil then
                for _, env in ipairs(initContainer.env) do
                  if env.valueFrom ~= nil and env.valueFrom.configMapKeyRef ~= nil then
                    key = getKey(pod.metadata.namespace, env.valueFrom.configMapKeyRef.name)
                    podConfigMaps[key] = true
                  end
                end
              end

              if initContainer.envFrom ~= nil then
                for _, envFrom in ipairs(initContainer.envFrom) do
                  if envFrom.configMapRef ~= nil then
                    key = getKey(pod.metadata.namespace,envFrom.configMapRef.name)
                    podConfigMaps[key] = true
                  end
                end
              end  

            end
          end    

          if pod.spec.volumes ~= nil then  
            for _, volume in ipairs(pod.spec.volumes) do
              if volume.configMap ~= nil then
                key = getKey(pod.metadata.namespace,volume.configMap.name)
                podConfigMaps[key] = true
              end

              if volume.projected ~= nil and volume.projected.sources ~= nil then
                for _, projectedResource in ipairs(volume.projected.sources) do
                  if projectedResource.configMap ~= nil then
                    key = getKey(pod.metadata.namespace,projectedResource.configMap.name)
                    podConfigMaps[key] = true
                  end
                end
              end
            end
          end
        end  

        return podConfigMaps
      end

      function evaluate()
        local hs = {}
        hs.message = ""

        local pods = {}
        local configMaps = {}
        local unusedConfigMaps = {}

        -- Separate configMaps and podsfrom the resources
        for _, resource in ipairs(resources) do
            local kind = resource.kind
            if kind == "ConfigMap" and not skipNamespace(resource.metadata.namespace) then
              table.insert(configMaps, resource)
            elseif kind == "Pod" then
              table.insert(pods, resource)
            end
        end

        podConfigMaps = configMapsUsedByPods(pods)

        for _, configMap in ipairs(configMaps) do
          key = getKey(configMap.metadata.namespace,configMap.metadata.name)
          if not podConfigMaps[key] then
            table.insert(unusedConfigMaps, {resource = configMap})
          end
        end

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