Merge #182

182: Run meilisearch as non-root user with readOnlyRootFilesystem r=alallema a=legal90

# Pull Request

## Related issue
- meilisearch/meilisearch#2051  (it's just a relevant issue raised on the meilisearch image level)

This PR was created in the continuation to our discussion here: #176 (comment)

## What does this PR do?

That PR changes the default behaviour of the chart so it runs meilisearch under a non-root user, following the principal of least permissions and improve the security posture:

- Enable `securityContext.readOnlyRootFilesystem: true` by default and mount required writable points:
  - `/tmp` as `emptyDir: {}` [1]
  - `/meili_data` as `emptyDir: {}` by default, or as a PVC if `persistence.enabled: true`

- Default values `fsGroup: 1000` and `fsGroupChangePolicy: OnRootMismatch` allow to keep backward compatibility with existing installations. If the data volume already has files previously created and owned by root (e.q. `persistence.enabled: true`), then k8s will automatically change the group ownership of these files to 1000, so they will still be writable by the non-privileged user in this new chart version. That happens automatically - no user action is needed. [2]

- **Small chance of backward incompatibility for some users:**  those users who already have `/tmp` mount configured via `volumes` and `volumeMounts` values, might get a failure in upgrade to this new version, because this volume is now declared in the template by default. The fix is simple - just remove the definition of /tmp from your custom values.

Due to that I'm bumping the minor version of the chart to 0.2.0. Please let me know if you think we should update it differently.

## Links 
[1] https://kubernetes.io/docs/concepts/storage/volumes/#emptydir
[2] https://kubernetes.io/docs/tasks/configure-pod-container/security-context/#configure-volume-permission-and-ownership-change-policy-for-pods

## PR checklist
Please check if your PR fulfills the following requirements:
- [x] Does this PR fix an existing issue, or have you listed the changes applied in the PR description (and why they are needed)?
- [x] Have you read the contributing guidelines?
- [x] Have you made sure that the title is accurate and descriptive of the changes?



Co-authored-by: Mikhail Zholobov <legal90@gmail.com>
Co-authored-by: Amélie <alallema@users.noreply.github.com>

charts/meilisearch/Chart.yaml

@@ -2,7 +2,7 @@ apiVersion: v1
 appVersion: "v1.2.0"
 description: A Helm chart for the Meilisearch search engine
 name: meilisearch
-version: 0.1.59
+version: 0.2.0
 icon: https://res.cloudinary.com/meilisearch/image/upload/v1597822872/Logo/logo_img.svg
 home: https://github.com/meilisearch/meilisearch-kubernetes/tree/main/charts/meilisearch
 maintainers:

charts/meilisearch/README.md

@@ -2,7 +2,7 @@
 
 A Helm chart for the Meilisearch search engine
 
-![Version: 0.1.58](https://img.shields.io/badge/Version-0.1.58-informational?style=flat-square) ![AppVersion: v1.2.0](https://img.shields.io/badge/AppVersion-v1.2.0-informational?style=flat-square)
+![Version: 0.2.0](https://img.shields.io/badge/Version-0.2.0-informational?style=flat-square) ![AppVersion: v1.2.0](https://img.shields.io/badge/AppVersion-v1.2.0-informational?style=flat-square)
 
 Helm works as a package manager to run pre-configured Kubernetes resources.
 
@@ -88,13 +88,18 @@ You can also use `auth.existingMasterKeySecret` to use an existing secret that h
 | persistence.volume.name | string | `"data"` |  |
 | podAnnotations | object | `{}` |  |
 | podLabels | object | `{}` | Additional labels to add to the pod(s) only |
-| podSecurityContext | object | `{}` |  |
+| podSecurityContext.fsGroup | int | `1000` |  |
+| podSecurityContext.fsGroupChangePolicy | string | `"OnRootMismatch"` |  |
+| podSecurityContext.runAsGroup | int | `1000` |  |
+| podSecurityContext.runAsNonRoot | bool | `true` |  |
+| podSecurityContext.runAsUser | int | `1000` |  |
 | readinessProbe.InitialDelaySeconds | int | `0` |  |
 | readinessProbe.periodSeconds | int | `10` |  |
 | replicaCount | int | `1` | Number of Meilisearch pods to run |
 | resources | object | `{}` | Resources allocation (Requests and Limits) |
 | securityContext.allowPrivilegeEscalation | bool | `false` |  |
 | securityContext.capabilities.drop[0] | string | `"ALL"` |  |
+| securityContext.readOnlyRootFilesystem | bool | `true` |  |
 | service | object | `{"annotations":{},"port":7700,"type":"ClusterIP"}` | Service HTTP port |
 | service.annotations | object | `{}` | Additional annotations for service |
 | service.type | string | `"ClusterIP"` | Kubernetes Service type |

charts/meilisearch/templates/statefulset.yaml

@@ -32,33 +32,34 @@ spec:
       securityContext:
         {{- toYaml .Values.podSecurityContext | nindent 8 }}
       {{- end }}
-      {{- if or .Values.persistence.enabled .Values.volumes }}
       volumes:
+        - name: tmp
+          emptyDir: {}
         {{- if .Values.persistence.enabled }}
         - name: {{ .Values.persistence.volume.name }}
           persistentVolumeClaim:
             claimName: {{ if .Values.persistence.existingClaim }}{{ .Values.persistence.existingClaim }}{{- else }}{{ include "meilisearch.fullname" . }}{{- end }}
+        {{- else }}
+        - name: {{ .Values.persistence.volume.name }}
+          emptyDir: {}
         {{- end }}
         {{- if .Values.volumes }}
 {{ toYaml .Values.volumes | indent 8 }}
         {{- end }}
-      {{- end }}
       containers:
         - name: {{ .Chart.Name }}
           image: "{{ .Values.image.repository }}:{{ .Values.image.tag }}"
           imagePullPolicy: {{ .Values.image.pullPolicy }}
           securityContext:
 {{ toYaml .Values.securityContext | indent 12 }}
-          {{- if or .Values.persistence.enabled .Values.volumeMounts }}
           volumeMounts:
-            {{- if .Values.persistence.enabled }}
+            - name: tmp
+              mountPath: /tmp
             - name: {{ .Values.persistence.volume.name }}
               mountPath: {{ .Values.persistence.volume.mountPath }}
-            {{- end }}
             {{- if .Values.volumeMounts }}
 {{ toYaml .Values.volumeMounts | indent 12 }}
             {{- end }}
-          {{- end }}
           envFrom:
           - configMapRef:
               name: {{ template "meilisearch.fullname" . }}-environment

charts/meilisearch/values.yaml

@@ -81,14 +81,19 @@ service:
 container:
   containerPort: 7700
 
-podSecurityContext: {}
+podSecurityContext:
+  runAsNonRoot: true
+  runAsUser: 1000
+  runAsGroup: 1000
+  fsGroup: 1000
+  fsGroupChangePolicy: OnRootMismatch
 
 securityContext:
   capabilities:
     drop:
       - ALL
   allowPrivilegeEscalation: false
-  # readOnlyRootFilesystem: true
+  readOnlyRootFilesystem: true
 
 ingress:
   # -- Enable ingress controller resource

manifests/meilisearch.yaml

@@ -75,9 +75,20 @@ spec:
         app.kubernetes.io/component: search-engine
         app.kubernetes.io/part-of: meilisearch
       annotations:
-        checksum/config: ae9884187319e63ffb542daf76a83b035abbfb6fe306768ab983e82d34048dca
+        checksum/config: 2feedcfe9e2a9425200a2c547238c64e882bd9160bf3a521e1dbab0e83ee246f
     spec:
       serviceAccountName: meilisearch
+      securityContext:
+        fsGroup: 1000
+        fsGroupChangePolicy: OnRootMismatch
+        runAsGroup: 1000
+        runAsNonRoot: true
+        runAsUser: 1000
+      volumes:
+        - name: tmp
+          emptyDir: {}
+        - name: data
+          emptyDir: {}
       containers:
         - name: meilisearch
           image: "getmeili/meilisearch:v1.2.0"
@@ -87,6 +98,12 @@ spec:
             capabilities:
               drop:
               - ALL
+            readOnlyRootFilesystem: true
+          volumeMounts:
+            - name: tmp
+              mountPath: /tmp
+            - name: data
+              mountPath: /meili_data
           envFrom:
           - configMapRef:
               name: meilisearch-environment