From 1eefbe0c7b5515b45e2dc71cd543ed2c0a83c476 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Paolo=20Chil=C3=A0?= <paolo.chila@elastic.co>
Date: Tue, 18 Feb 2025 17:08:17 +0100
Subject: [PATCH] Add statePersistence value to helm chart presets (#6803)

* Add statePersistence value to helm chart presets
---
 .../examples/eck/rendered/manifest.yaml       |  5 +-
 .../netflow-service/rendered/manifest.yaml    |  4 +-
 .../rendered/manifest.yaml                    |  4 +-
 .../user-cluster-role/rendered/manifest.yaml  |  4 +-
 .../templates/agent/_helpers.tpl              | 69 +++++++++++++++++++
 .../templates/agent/eck/_pod_template.yaml    |  9 +--
 .../templates/agent/k8s/_pod_template.yaml    | 39 ++---------
 deploy/helm/elastic-agent/values.schema.json  |  9 +++
 deploy/helm/elastic-agent/values.yaml         |  8 +--
 9 files changed, 98 insertions(+), 53 deletions(-)

diff --git a/deploy/helm/elastic-agent/examples/eck/rendered/manifest.yaml b/deploy/helm/elastic-agent/examples/eck/rendered/manifest.yaml
index d033d5fb094..d753d27c45c 100644
--- a/deploy/helm/elastic-agent/examples/eck/rendered/manifest.yaml
+++ b/deploy/helm/elastic-agent/examples/eck/rendered/manifest.yaml
@@ -1033,6 +1033,10 @@ spec:
         - hostPath:
             path: /var/log
           name: varlog
+        - hostPath:
+            path: /etc/elastic-agent/default/agent-pernode-example/state
+            type: DirectoryOrCreate
+          name: agent-data
 ---
 # Source: elastic-agent/templates/agent/eck/deployment.yaml
 apiVersion: agent.k8s.elastic.co/v1alpha1
@@ -1093,7 +1097,6 @@ spec:
             privileged: false
             runAsGroup: 1000
             runAsUser: 1000
-          volumeMounts: null
         dnsPolicy: ClusterFirstWithHostNet
         nodeSelector:
           kubernetes.io/os: linux
diff --git a/deploy/helm/elastic-agent/examples/netflow-service/rendered/manifest.yaml b/deploy/helm/elastic-agent/examples/netflow-service/rendered/manifest.yaml
index d324b371dae..8ed9f874e48 100644
--- a/deploy/helm/elastic-agent/examples/netflow-service/rendered/manifest.yaml
+++ b/deploy/helm/elastic-agent/examples/netflow-service/rendered/manifest.yaml
@@ -158,9 +158,7 @@ spec:
           subPath: agent.yml
       dnsPolicy: ClusterFirstWithHostNet
       volumes:
-      - hostPath:
-          path: /etc/elastic-agent/default/agent-netflow-example/state
-          type: DirectoryOrCreate
+      - emptyDir: {}
         name: agent-data
       - name: config
         secret:
diff --git a/deploy/helm/elastic-agent/examples/nginx-custom-integration/rendered/manifest.yaml b/deploy/helm/elastic-agent/examples/nginx-custom-integration/rendered/manifest.yaml
index 5c445c5e5be..88a00759d5e 100644
--- a/deploy/helm/elastic-agent/examples/nginx-custom-integration/rendered/manifest.yaml
+++ b/deploy/helm/elastic-agent/examples/nginx-custom-integration/rendered/manifest.yaml
@@ -107,9 +107,7 @@ spec:
           subPath: agent.yml
       dnsPolicy: ClusterFirstWithHostNet
       volumes:
-      - hostPath:
-          path: /etc/elastic-agent/default/agent-nginx-example/state
-          type: DirectoryOrCreate
+      - emptyDir: {}
         name: agent-data
       - name: config
         secret:
diff --git a/deploy/helm/elastic-agent/examples/user-cluster-role/rendered/manifest.yaml b/deploy/helm/elastic-agent/examples/user-cluster-role/rendered/manifest.yaml
index 6aef8be15d9..e559b52b54a 100644
--- a/deploy/helm/elastic-agent/examples/user-cluster-role/rendered/manifest.yaml
+++ b/deploy/helm/elastic-agent/examples/user-cluster-role/rendered/manifest.yaml
@@ -147,9 +147,7 @@ spec:
       dnsPolicy: ClusterFirstWithHostNet
       serviceAccountName: agent-nginx-example
       volumes:
-      - hostPath:
-          path: /etc/elastic-agent/default/agent-nginx-example/state
-          type: DirectoryOrCreate
+      - emptyDir: {}
         name: agent-data
       - name: config
         secret:
diff --git a/deploy/helm/elastic-agent/templates/agent/_helpers.tpl b/deploy/helm/elastic-agent/templates/agent/_helpers.tpl
index 563664f8866..c45971475c1 100644
--- a/deploy/helm/elastic-agent/templates/agent/_helpers.tpl
+++ b/deploy/helm/elastic-agent/templates/agent/_helpers.tpl
@@ -120,6 +120,18 @@ Validate and initialise the defined agent presets
 {{/* merge the default leader election with the leader election from the preset giving priority to the one from the preset */}}
 {{- $presetLeaderElection := mergeOverwrite dict $defaultLeaderElection ($presetProviders).kubernetes_leaderelection -}}
 {{- $_ := set $presetProviders "kubernetes_leaderelection" $presetLeaderElection -}}
+{{/* set a sensible default to preset.statePersistence if no value is already present in the preset */}}
+{{- if empty ($presetVal).statePersistence -}}
+{{- if eq ($presetMode) "daemonset" -}}
+{{- $_ := set $presetVal "statePersistence" "HostPath" -}}
+{{- else if eq ($presetMode) "deployment" -}}
+{{- $_ := set $presetVal "statePersistence" "EmptyDir" -}}
+{{- else if eq ($presetMode) "statefulset" -}}
+{{- $_ := set $presetVal "statePersistence" "EmptyDir" -}}
+{{- else -}}
+fail printf "Unsupported mode %v for preset %v" ($presetMode) $($presetName)
+{{- end -}}
+{{- end -}}
 {{- end -}}
 {{- end -}}
 
@@ -323,3 +335,60 @@ app.kubernetes.io/version: {{ .Values.agent.version}}
 {{- end -}}
 {{- $_ := set $preset "outputs" $presetOutputs -}}
 {{- end -}}
+
+{{/*
+Render a yaml with volumes and volumeMounts keys, rendering state volumes and extra volumes and their respective mounts
+*/}}
+{{- define "elasticagent.preset.render.volumes" -}}
+{{- $ := index . 0 -}}
+{{- $presetVal := index . 1 -}}
+{{- $agentName := index . 2 -}}
+volumes:
+{{- $definedAgentStateVolume := false -}}
+  {{- with ($presetVal).extraVolumes }}
+  {{- . | toYaml | nindent 2 }}
+  {{- range $idx, $volume := . -}}
+  {{- if eq $definedAgentStateVolume false -}}
+  {{- if eq ($volume).name "agent-data" -}}
+  {{- $definedAgentStateVolume = true}}
+  {{- end -}}
+  {{- end -}}
+  {{- end -}}
+  {{- end }}
+  {{- if ne ($presetVal).statePersistence "None" }}
+  {{- if eq $definedAgentStateVolume false }}
+  - name: agent-data
+    {{- if eq ($presetVal).statePersistence "HostPath" }}
+    hostPath:
+      {{- if eq $.Values.agent.fleet.enabled true }}
+      {{/* different state hostPath for managed agents */}}
+      path: /etc/elastic-agent/{{$.Release.Namespace}}/{{$agentName}}-managed/state
+      {{- else }}
+      {{/* different state hostPath for standalone agents */}}
+      path: /etc/elastic-agent/{{$.Release.Namespace}}/{{$agentName}}/state
+      {{- end }}
+      type: DirectoryOrCreate
+    {{- else if eq ($presetVal).statePersistence "EmptyDir" }}
+    emptyDir: {}
+    {{- end }}
+  {{- end }}
+  {{- end }}
+volumeMounts:
+  {{- $definedAgentStateVolumeMount := false -}}
+  {{- with ($presetVal).extraVolumeMounts }}
+  {{- . | toYaml | nindent 2}}
+  {{- range $idx, $volumeMount := . -}}
+  {{- if eq $definedAgentStateVolumeMount false -}}
+  {{- if eq ($volumeMount).name "agent-data" -}}
+  {{- $definedAgentStateVolumeMount = true}}
+  {{- end -}}
+  {{- end -}}
+  {{- end -}}
+  {{- end }}
+  {{- if ne ($presetVal).statePersistence "None" }}
+  {{- if eq $definedAgentStateVolumeMount false }}
+  - name: agent-data
+    mountPath: /usr/share/elastic-agent/state
+  {{- end }}
+  {{- end }}
+{{- end -}}
\ No newline at end of file
diff --git a/deploy/helm/elastic-agent/templates/agent/eck/_pod_template.yaml b/deploy/helm/elastic-agent/templates/agent/eck/_pod_template.yaml
index 4b7e4b8b295..0848686f059 100644
--- a/deploy/helm/elastic-agent/templates/agent/eck/_pod_template.yaml
+++ b/deploy/helm/elastic-agent/templates/agent/eck/_pod_template.yaml
@@ -2,6 +2,7 @@
 {{- $ := index . 0 -}}
 {{- $presetVal := index . 1 -}}
 {{- $agentName := index . 2 }}
+{{- $agentVolumes := (include "elasticagent.preset.render.volumes"  (list $ $presetVal $agentName) | fromYaml) -}}
 apiVersion: v1
 kind: PodTemplate
 template:
@@ -39,10 +40,10 @@ template:
     topologySpreadConstraints:
       {{- . | toYaml | nindent 6 }}
     {{- end }}
+    {{- with ($agentVolumes).volumes }}
     volumes:
-      {{- with ($presetVal).extraVolumes }}
       {{- . | toYaml | nindent 6 }}
-      {{- end }}
+    {{- end }}
     {{- with ($presetVal).initContainers }}
     initContainers:
       {{- . | toYaml | nindent 6 }}
@@ -90,10 +91,10 @@ template:
           {{- end }}
         {{- end }}
         {{- end }}
+        {{- with ($presetVal).extraVolumeMounts }}
         volumeMounts:
-          {{- with ($presetVal).extraVolumeMounts }}
           {{- . | toYaml | nindent 10 }}
-          {{- end }}
+        {{- end }}
         env:
           - name: NODE_NAME
             valueFrom:
diff --git a/deploy/helm/elastic-agent/templates/agent/k8s/_pod_template.yaml b/deploy/helm/elastic-agent/templates/agent/k8s/_pod_template.yaml
index afc8c5ab05d..6b74e6323a2 100644
--- a/deploy/helm/elastic-agent/templates/agent/k8s/_pod_template.yaml
+++ b/deploy/helm/elastic-agent/templates/agent/k8s/_pod_template.yaml
@@ -2,6 +2,7 @@
 {{- $ := index . 0 -}}
 {{- $presetVal := index . 1 -}}
 {{- $agentName := index . 2 }}
+{{- $agentVolumes := (include "elasticagent.preset.render.volumes"  (list $ $presetVal $agentName) | fromYaml) -}}
 apiVersion: v1
 kind: PodTemplate
 template:
@@ -40,28 +41,8 @@ template:
       {{- . | toYaml | nindent 6 }}
     {{- end }}
     volumes:
-      {{- $definedAgentStateVolume := false -}}
-      {{- with ($presetVal).extraVolumes }}
+      {{- with ($agentVolumes).volumes }}
       {{- . | toYaml | nindent 6 }}
-      {{- range $idx, $volume := . -}}
-      {{- if eq $definedAgentStateVolume false -}}
-      {{- if eq ($volume).name "agent-data" -}}
-      {{- $definedAgentStateVolume = true}}
-      {{- end -}}
-      {{- end -}}
-      {{- end -}}
-      {{- end }}
-      {{- if eq $definedAgentStateVolume false }}
-      - name: agent-data
-        hostPath:
-          {{- if eq $.Values.agent.fleet.enabled true }}
-          {{/* different state hostPath for managed agents */}}
-          path: /etc/elastic-agent/{{$.Release.Namespace}}/{{$agentName}}-managed/state
-          {{- else }}
-          {{/* different state hostPath for standalone agents */}}
-          path: /etc/elastic-agent/{{$.Release.Namespace}}/{{$agentName}}/state
-          {{- end }}
-          type: DirectoryOrCreate
       {{- end }}
       {{/* standalone mode so config is static */}}
       - name: config
@@ -117,20 +98,8 @@ template:
         {{- end }}
         {{- end }}
         volumeMounts:
-          {{- $definedAgentStateVolumeMount := false -}}
-          {{- with ($presetVal).extraVolumeMounts }}
-          {{- . | toYaml | nindent 10}}
-          {{- range $idx, $volumeMount := . -}}
-          {{- if eq $definedAgentStateVolumeMount false -}}
-          {{- if eq ($volumeMount).name "agent-data" -}}
-          {{- $definedAgentStateVolumeMount = true}}
-          {{- end -}}
-          {{- end -}}
-          {{- end -}}
-          {{- end }}
-          {{- if eq $definedAgentStateVolumeMount false }}
-          - name: agent-data
-            mountPath: /usr/share/elastic-agent/state
+          {{- with ($agentVolumes).volumeMounts }}
+          {{- . | toYaml | nindent 10 }}
           {{- end }}
           - name: config
             mountPath: /etc/elastic-agent/agent.yml
diff --git a/deploy/helm/elastic-agent/values.schema.json b/deploy/helm/elastic-agent/values.schema.json
index 509f2812227..a55a699bfe0 100644
--- a/deploy/helm/elastic-agent/values.schema.json
+++ b/deploy/helm/elastic-agent/values.schema.json
@@ -1356,6 +1356,15 @@
                         ]
                     ]
                 },
+                "statePersistence": {
+                    "type": "string",
+                    "enum": [
+                        "HostPath",
+                        "EmptyDir",
+                        "None"
+                    ],
+                    "description": "Volume type used for Agent state persistence."
+                },
                 "extraVolumes": {
                     "type": "array",
                     "items": {
diff --git a/deploy/helm/elastic-agent/values.yaml b/deploy/helm/elastic-agent/values.yaml
index dbe837d9bc9..fd4576aa84c 100644
--- a/deploy/helm/elastic-agent/values.yaml
+++ b/deploy/helm/elastic-agent/values.yaml
@@ -396,6 +396,7 @@ agent:
     #    tolerations: []
     #    topologySpreadConstraints: []
     #    extraEnv: []
+    #    statePersistence: [HostPath, EmptyDir, None]
     #    extraVolumes: []
     #    extraVolumeMounts: []
     #    https://github.com/elastic/elastic-agent/blob/main/_meta/elastic-agent.yml
@@ -418,10 +419,8 @@ agent:
           memory: 400Mi
       nodeSelector:
         kubernetes.io/os: linux
-      extraVolumes:
-        # override the default agent-data volume and make it an emptyDir
-        - name: agent-data
-          emptyDir: {}
+      statePersistence: EmptyDir
+      extraVolumes: []
       extraEnvs:
         - name: ELASTIC_NETINFO
           value: "false"
@@ -454,6 +453,7 @@ agent:
           memory: 400Mi
       nodeSelector:
         kubernetes.io/os: linux
+      statePersistence: HostPath
       extraEnvs:
         - name: ELASTIC_NETINFO
           value: "false"