docs: add ClickHouse cluster documentation

README.md

@@ -316,6 +316,44 @@ populated with random value to ensure uniqueness.
 
 In order for SSL to work without warnings the CA certificate needs to be mounted in the relevant pods. This is not yet implemented as due to an [outstanding issue in tutor](https://github.com/overhangio/tutor/issues/791) that had not yet been completed at the time of writing.
 
+### ClickHouse Cluster
+
+ClickHouse is needed for running Aspects, however for medium/large instances one single ClickHouse node can be
+a bottleneck for Aspects and the default ClickHouse deployment in Aspects can take down other services running on the
+same node as the ClickHouse pod. In case you are interested on running a ClickHouse cluster, you can enable the
+Altinity ClickHouse Operator and follow the templates available on `charts/examples/clickhouse` to setup a ClickHouseKeeper
+quorum (needed for replication) and a ClickHouse cluster based on your needs.
+
+Once your cluster is created and working on Kubernetes, you need to update your installation settings:
+
+```yaml
+# See the clickhouse-installation.yml template for more details
+CLICKHOUSE_ADMIN_USER: default
+CLICKHOUSE_ADMIN_PASSWORD: change_me
+CLICKHOUSE_CLUSTER_NAME: openedx-demo
+# Set the first ClickHouse node as the DDL node.
+CLICKHOUSE_CLUSTER_DDL_NODE_HOST: chi-clickhouse-{{CLICKHOUSE_CLUSTER_NAME}}-0-0.{{namespace}}
+CLICKHOUSE_HOST: clickhouse-clickhouse.{{namespace}}
+CLICKHOUSE_SECURE_CONNECTION: false
+RUN_CLICKHOUSE: false
+```
+
+For multitenancy you have two options, either have multiple ClickHouse clusters or use different databases and users:
+
+*Using different users and databases*: Make sure to update the users and databases on your config:
+
+```yaml
+ASPECTS_CLICKHOUSE_CMS_USER: openedx_demo_ch_cms
+ASPECTS_CLICKHOUSE_LRS_USER: openedx_demo_ch_lrs
+ASPECTS_CLICKHOUSE_REPORT_USER: openedx_demo_ch_report
+ASPECTS_CLICKHOUSE_VECTOR_USER: openedx_demo_ch_vector
+ASPECTS_XAPI_DATABASE: openedx_demo_xapi
+ASPECTS_EVENT_SINK_DATABASE: openedx_demo_event_sink
+ASPECTS_VECTOR_DATABASE: openedx_demo_openedx
+DBT_PROFILE_TARGET_DATABASE: openedx_demo_reporting
+```
+
+
 ## Extended Documentation
 
 ### How to uninstall this chart

charts/examples/clickhouse/clickhouse-installation.yml

@@ -0,0 +1,76 @@
+---
+apiVersion: "clickhouse.altinity.com/v1"
+kind: "ClickHouseInstallation"
+metadata:
+  name: "clickhouse"
+spec:
+  configuration:
+    clusters:
+      - name: "openedx-demo"
+        layout:
+          shardsCount: 1 # Shards have not been tested with Aspects and we don't recommend it.
+          replicasCount: 2 # Scale as you need/can
+        templates:
+          podTemplate: server
+          volumeClaimTemplate: storage
+    users:
+      test/networks/ip:
+        - "::/0"
+      test/profile: default
+      test/password: change_me
+      test/quota: default
+      # Default permissions needed for user creation
+      test/access_management: 1
+      test/named_collection_control: 1
+      test/show_named_collections: 1
+      test/show_named_collections_secrets: 1
+    zookeeper:
+      nodes:
+        - host: clickhouse-keeper-0.clickhouse-keeper-headless
+        - host: clickhouse-keeper-1.clickhouse-keeper-headless
+        - host: clickhouse-keeper-2.clickhouse-keeper-headless
+    files:
+      # Enable user replication
+      users-replication.xml: |
+        <clickhouse>
+          <user_directories replace="replace">
+            <users_xml>
+              <path>/etc/clickhouse-server/users.xml</path>
+            </users_xml>
+            <replicated>
+              <zookeeper_path>/clickhouse/access/</zookeeper_path>
+            </replicated>
+          </user_directories>
+        </clickhouse>
+      # Enable function replication
+      functions-replication.xml: |
+        <clickhouse>
+            <user_defined_zookeeper_path>/udf</user_defined_zookeeper_path>
+        </clickhouse>
+  templates:
+    podTemplates:
+      - name: server
+        spec:
+          containers:
+            - name: clickhouse
+              image: clickhouse/clickhouse-server:24.8
+          # If you are running a dedicated node group for ClickHouse (and you should)
+          # make sure to add it tolerations.
+          tolerations:
+          - key: "clickhouseInstance"
+            operator: "Exists"
+            effect: "NoSchedule"
+          # Optional: set the nodegroup name
+          nodeSelector:
+            eks.amazonaws.com/nodegroup: clickhouse_worker
+    volumeClaimTemplates:
+      - name: storage
+        # Do not delete PV if installation is deleted. If a new ClickHouseInstallation is created
+        # data will be re-used, allowing recovery of data
+        reclaimPolicy: Retain
+        spec:
+          accessModes:
+            - ReadWriteOnce
+          resources:
+            requests:
+              storage: 50Gi

charts/examples/clickhouse/clickhouse-keeper.yml

@@ -0,0 +1,86 @@
+apiVersion: "clickhouse-keeper.altinity.com/v1"
+kind: "ClickHouseKeeperInstallation"
+metadata:
+  name: clickhouse-keeper
+spec:
+  configuration:
+    clusters:
+      - name: "openedx-demo"
+        layout:
+          # ClickHouseKeeper needs at least tree pods to form a Quorum for high
+          # availability.
+          replicasCount: 3
+    settings:
+      logger/level: "trace"
+      logger/console: "true"
+      listen_host: "0.0.0.0"
+      keeper_server/storage_path: /var/lib/clickhouse-keeper
+      keeper_server/tcp_port: "2181"
+      keeper_server/four_letter_word_white_list: "*"
+      keeper_server/coordination_settings/raft_logs_level: "information"
+      keeper_server/raft_configuration/server/port: "9444"
+      prometheus/endpoint: "/metrics"
+      prometheus/port: "7000"
+      prometheus/metrics: "true"
+      prometheus/events: "true"
+      prometheus/asynchronous_metrics: "true"
+      prometheus/status_info: "false"
+  templates:
+    podTemplates:
+      - name: default
+        spec:
+          # affinity removed to allow use in single node test environment
+          affinity:
+            podAntiAffinity:
+              requiredDuringSchedulingIgnoredDuringExecution:
+                - labelSelector:
+                    matchExpressions:
+                      - key: "app"
+                        operator: In
+                        values:
+                          - clickhouse-keeper
+                  topologyKey: "kubernetes.io/hostname"
+          containers:
+            - name: clickhouse-keeper
+              imagePullPolicy: IfNotPresent
+              # Make sure to keep this up to date with the ClickHouse compatible version
+              image: "clickhouse/clickhouse-keeper:24.8-alpine"
+              resources:
+                requests:
+                  memory: "256M"
+                  cpu: "0.25"
+                limits:
+                  memory: "1Gi"
+                  cpu: "1"
+          priorityClassName: clickhouse-priority
+    volumeClaimTemplates:
+      - name: default
+        spec:
+          accessModes:
+            - ReadWriteOnce
+          resources:
+            requests:
+              storage: 10Gi
+      - name: snapshot-storage-path
+        spec:
+          accessModes:
+            - ReadWriteOnce
+          resources:
+            requests:
+              storage: 10Gi
+      - name: log-storage-path
+        spec:
+          accessModes:
+            - ReadWriteOnce
+          resources:
+            requests:
+              storage: 10Gi
+
+---
+apiVersion: scheduling.k8s.io/v1
+kind: PriorityClass
+metadata:
+  name: clickhouse-priority
+value: 1000000
+globalDefault: false
+description: "This priority class should be used for ClickHouse service pods only."

charts/harmony-chart/values.yaml

@@ -374,3 +374,4 @@ clickhouse-operator:
   secret:
     username: "change_me"
     password: "change_me"
+  fullnameOverride: "clickhouse-operator"