Readd memcached props and update guide

Signed-off-by: relusc <rene.schach_ext@external.mail.schwarz>

Author: relusc

README.md

@@ -375,6 +375,10 @@ Kubernetes: `^1.19.0-0`
 | ingress.​tls | list | `[]` |  |
 | memberlist.​service.​annotations | object | `{}` |  |
 | memberlist.​service.​labels | object | `{}` |  |
+| memcached-blocks | object | `{}` |  |
+| memcached-blocks-index | object | `{}` |  |
+| memcached-blocks-metadata | object | `{}` |  |
+| memcached-frontend | object | `{}` | Memcached properties External installations of memcached can be referenced here |
 | nginx.​affinity | object | `{}` |  |
 | nginx.​annotations | object | `{}` |  |
 | nginx.​autoscaling.​behavior | object | `{}` | Ref: https://kubernetes.io/docs/tasks/run-application/horizontal-pod-autoscale/#support-for-configurable-scaling-behavior |

docs/guides/configure_memcached.markdown

@@ -17,42 +17,27 @@ has_toc: false
 ---
 # Configuring memcached as the caching store
 
-Correctly configuring memcached for your needs is a very delicate  task. But courtesy of [@thobianchi](https://github.com/thobianchi) this might be a good start.
+If you want to use [memcached](https://memcached.org/) as a caching store, you first have to deploy it separately (e.g. via separate helm chart). The existing deployments can be referenced in the `values.yaml` so that they are used as caching stores.
+
+Here's how to configure the memcached's via the values:
 
 {% raw %}
 ```yaml
-index_cache:
-  backend: memcached
-  memcached:
-    addresses: 'dns+{{ include "cortex.fullname" $ }}-memcached-blocks-index:11211'
-    timeout: 300ms
-    max_idle_connections: 750
-    max_async_concurrency: 100
-    max_async_buffer_size: 10000000
-    max_get_multi_concurrency: 750
-    max_get_multi_batch_size: 1000
-    max_item_size: 16777216
-chunks_cache:
-  backend: memcached
-  memcached:
-    addresses: 'dns+{{ include "cortex.fullname" $ }}-memcached-blocks:11211'
-    timeout: 300ms
-    max_idle_connections: 750
-    max_async_concurrency: 100
-    max_async_buffer_size: 10000000
-    max_get_multi_concurrency: 750
-    max_get_multi_batch_size: 1000
-    max_item_size: 33554432
-metadata_cache:
-  backend: memcached
-  memcached:
-    addresses: 'dns+{{ include "cortex.fullname" $ }}-blocks-metadata:11211'
-    timeout: 300ms
-    max_idle_connections: 750
-    max_async_concurrency: 100
-    max_async_buffer_size: 10000000
-    max_get_multi_concurrency: 750
-    max_get_multi_batch_size: 1000
-    max_item_size: 16777216
+memcached-frontend:
+  # reference pre-existing service here
+  serviceName: cortex-memcached-frontend
+  containerPort: 11211
+
+memcached-blocks-index:
+  serviceName: cortex-memcached-blocks-index
+  containerPort: 11211
+
+memcached-blocks:
+  serviceName: cortex-memcached-blocks
+  containerPort: 11211
+
+memcached-blocks-metadata:
+  serviceName: cortex-memcached-blocks-metadata
+  containerPort: 11211
 ```
 {% endraw %}

templates/_helpers.tpl

@@ -81,6 +81,33 @@ app.kubernetes.io/name: {{ include "cortex.name" . }}
 app.kubernetes.io/instance: {{ .Release.Name }}
 {{- end }}
 
+{{/*
+Create configuration parameters for memcached configuration
+*/}}
+{{- define "cortex.memcached" -}}
+{{- if index .Values "memcached-blocks-index" "serviceName" }}
+- "-blocks-storage.bucket-store.index-cache.backend=memcached"
+- "-blocks-storage.bucket-store.index-cache.memcached.addresses=dns+{{ .memcached-blocks-index.serviceName }}.{{ .Release.Namespace }}.svc.{{ .Values.clusterDomain }}:{{ memcached-blocks-index.containerPort }}"
+{{- end -}}
+{{- if index .Values "memcached-blocks" "serviceName" }}
+- "-blocks-storage.bucket-store.chunks-cache.backend=memcached"
+- "-blocks-storage.bucket-store.chunks-cache.memcached.addresses=dns+{{ .memcached-blocks.serviceName }}.{{ .Release.Namespace }}.svc.{{ .Values.clusterDomain }}:{{ memcached-blocks.containerPort }}"
+{{- end -}}
+{{- if index .Values "memcached-blocks-metadata" "serviceName" }}
+- "-blocks-storage.bucket-store.metadata-cache.backend=memcached"
+- "-blocks-storage.bucket-store.metadata-cache.memcached.addresses=dns+{{ .memcached-blocks-metadata.serviceName }}.{{ .Release.Namespace }}.svc.{{ .Values.clusterDomain }}:{{ memcached-blocks-metadata.containerPort }}"
+{{- end -}}
+{{- end -}}
+
+{{/*
+Create configuration for frontend memcached configuration
+*/}}
+{{- define "cortex.frontend-memcached" -}}
+{{- if index .Values "memcached-frontend" "serviceName" }}
+- "-frontend.memcached.addresses=dns+{{ .memcached-frontend.serviceName }}.{{ .Release.Namespace }}.svc.{{ .Values.clusterDomain }}:{{ memcached-frontend.containerPort }}"
+{{- end -}}
+{{- end -}}
+
 {{/*
 Determine the policy api version
 */}}

templates/compactor/compactor-statefulset.yaml

@@ -107,6 +107,7 @@ spec:
           args:
             - "-target=compactor"
             - "-config.file=/etc/cortex/cortex.yaml"
+            {{- include "cortex.memcached" . | nindent 12}}
             {{- range $key, $value := .Values.compactor.extraArgs }}
             - "-{{ $key }}={{ $value }}"
             {{- end }}

templates/ingester/ingester-dep.yaml

@@ -54,6 +54,7 @@ spec:
           args:
             - "-target=ingester"
             - "-config.file=/etc/cortex/cortex.yaml"
+            {{- include "cortex.memcached" . | nindent 12}}
             {{- range $key, $value := .Values.ingester.extraArgs }}
             - "-{{ $key }}={{ $value }}"
             {{- end }}

templates/ingester/ingester-statefulset.yaml

@@ -110,6 +110,7 @@ spec:
           args:
             - "-target=ingester"
             - "-config.file=/etc/cortex/cortex.yaml"
+            {{- include "cortex.memcached" . | nindent 12}}
             {{- range $key, $value := .Values.ingester.extraArgs }}
             - "-{{ $key }}={{ $value }}"
             {{- end }}

templates/querier/querier-dep.yaml

@@ -58,6 +58,7 @@ spec:
           {{- if and .Values.query_frontend.enabled (not .Values.query_scheduler.enabled) }}
             - "-querier.frontend-address={{ template "cortex.queryFrontendFullname" . }}-headless.{{ .Release.Namespace }}.svc.{{ .Values.clusterDomain }}:{{ .Values.config.server.grpc_listen_port }}"
           {{- end }}
+          {{- include "cortex.memcached" . | nindent 12}}
           {{- range $key, $value := .Values.querier.extraArgs }}
             - "-{{ $key }}={{ $value }}"
           {{- end }}

templates/query-frontend/query-frontend-dep.yaml

@@ -50,6 +50,7 @@ spec:
           args:
             - "-target=query-frontend"
             - "-config.file=/etc/cortex/cortex.yaml"
+            {{- include "cortex.frontend-memcached" . | nindent 12 }}
           {{- if .Values.query_scheduler.enabled }}
             - "-frontend.scheduler-address={{ template "cortex.querySchedulerFullname" . }}-headless.{{ .Release.Namespace }}.svc.{{ .Values.clusterDomain }}:{{ .Values.config.server.grpc_listen_port }}"
           {{- end }}

templates/ruler/ruler-dep.yaml

@@ -112,6 +112,7 @@ spec:
             - "-ruler.alertmanager-url=http://{{ template "cortex.alertmanagerFullname" . }}.{{ .Release.Namespace }}.svc.{{ .Values.clusterDomain }}:{{ .Values.config.server.http_listen_port }}/api/prom/alertmanager/"
               {{- end }}
             {{- end }}
+            {{- include "cortex.memcached" . | nindent 12}}
           {{- range $key, $value := .Values.ruler.extraArgs }}
             - "-{{ $key }}={{ $value }}"
           {{- end }}

templates/store-gateway/store-gateway-statefulset.yaml

@@ -110,6 +110,7 @@ spec:
           args:
             - "-target=store-gateway"
             - "-config.file=/etc/cortex/cortex.yaml"
+            {{- include "cortex.memcached" . | nindent 12}}
             {{- range $key, $value := .Values.store_gateway.extraArgs }}
             - "-{{ $key }}={{ $value }}"
             {{- end }}