Support nested path in confd configmap

[clamoriniere]

What does this PR do?

Support nested confd path to allow multi configuration files for a check type

• Add Items []corev1.KeyToPath in ConfigDirSpec which allow to map a configmap key to a specific path.

type ConfigDirSpec struct {
	// ConfigMapName name of a ConfigMap used to mount a directory.
	ConfigMapName string `json:"configMapName,omitempty"`
	// items mapping between configMap data key and file path mount.
	Items []corev1.KeyToPath `json:"items,omitempty"`
}

• Fix conflict between "kuberenetesStateCore" config and clusterAgent.conf.confd.

Motivation

Some checks that can be schedule by the cluster-agent can require to have
several instances.

Additional Notes

N/A

Describe your test plan

Two 2 examples are present in the /examples/datadogagent/ folder:

• datadog-agent-ksm-core-custom-conf.yaml -> mount 3 differents configuration in /etc/datadog-agent/kubernetes_state_core.d/
• datadog-agent-cluster-agent-confd.yaml -> mount a nested file in /etc/datadog-agent/conf.d/test.d/test.yaml

another extra test can be to enable "kuberenetesStateCore" with a custom config + a clusterAgent.conf.confd config.

apiVersion: datadoghq.com/v1alpha1
kind: DatadogAgent
metadata:
  name: datadog
spec:
  ClusterName: ced-test
  credentials:
    apiKey: <DATADOG_API_KEY>
    appKey: <DATADOG_APP_KEY>
  features:
    orchestratorExplorer:
      enabled: true
    kubeStateMetricsCore:
      enabled: true
      conf:
        configMap:
          name: cluster-agent-ksm-conf
  agent:
    image:
      name: "gcr.io/datadoghq/agent:latest"
  clusterAgent:
    image:
      name: "gcr.io/datadoghq/cluster-agent:latest"
    config:
      confd:
        configMapName: cluster-agent-confd
        items:
        - key: test
          path: test.d/test.yaml
      clusterChecksEnabled: true
  clusterChecksRunner:
    image:
      name: "gcr.io/datadoghq/agent:latest"
---
apiVersion: v1
kind: ConfigMap
metadata:
  name: cluster-agent-confd
data:
  test: |-
    init_config:
    instances:
---
apiVersion: v1
kind: ConfigMap
metadata:
  name: cluster-agent-ksm-core-conf
data:
  pods.yaml: |-
    cluster_check: true
    init_config:
    instances:
      - collectors:
        - pods
  nodes.yaml: |-
    cluster_check: true
    init_config:
    instances:
      - collectors:
        - nodes
  others.yaml: |-
    cluster_check: true
    init_config:
    instances:
      - collectors:
        - secrets
        - services
        - resourcequotas
        - replicationcontrollers
        - limitranges
        - persistentvolumeclaims
        - persistentvolumes
        - namespaces
        - endpoints
        - daemonsets
        - deployments
        - replicasets
        - statefulsets
        - cronjobs
        - jobs
        - horizontalpodautoscalers
        - poddisruptionbudgets
        - storageclasses
        - volumeattachments

[codecov-commenter]

Codecov Report

Merging #335 (62e8d3e) into main (17299c9) will increase coverage by 0.04%.
The diff coverage is 64.36%.

@@            Coverage Diff             @@
##             main     #335      +/-   ##
==========================================
+ Coverage   63.44%   63.49%   +0.04%     
==========================================
  Files          60       61       +1     
  Lines        6614     6686      +72     
==========================================
+ Hits         4196     4245      +49     
- Misses       2116     2134      +18     
- Partials      302      307       +5     

Flag	Coverage Δ
unittests	63.49% <64.36%> (+0.04%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
api/v1alpha1/datadogagent_types.go	100.00% <ø> (ø)
controllers/datadogagent/kubestatemetrics.go	85.39% <ø> (ø)
controllers/datadogagent/utils.go	83.41% <37.50%> (-0.40%)	⬇️
controllers/datadogagent/builder.go	66.10% <66.10%> (ø)
controllers/datadogagent/clusteragent.go	70.45% <70.00%> (+0.65%)	⬆️

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[ahmed-mez]

thank you @clamoriniere !