thanos: add query-frontend in-memory cache

roles/prometheus/defaults/main.yml

@@ -19,3 +19,5 @@ alert_playbook_url: "https://playbooks"
 
 # Custom blackbox probes.
 prometheus_custom_blackbox_probes: {}
+
+thanos_query_frontend_cache_size: '50MB'

roles/prometheus/handlers/main.yml

@@ -32,3 +32,9 @@
     name: docker-prometheus-karma.service
     state: restarted
   listen: "reload karma"
+
+- name: restart thanos
+  systemd:
+    name: docker-prometheus-thanos.service
+    state: restarted
+  listen: "reload thanos"

roles/prometheus/tasks/prometheus.yml

@@ -70,3 +70,9 @@
     src: karma.yml.j2
     dest: "/etc/karma/float.yml"
   notify: "reload karma"
+
+- name: Install Thanos query-frontend cache configuration
+  template:
+    src: query-frontend-cache.yml.j2
+    dest: "/etc/thanos/query-frontend-cache.yml"
+  notify: "reload thanos"

roles/prometheus/templates/query-frontend-cache.yml.j2

+type: IN-MEMORY
+config:
+  max_size: "{{ thanos_query_frontend_cache_size }}"

services.yml.default

@@ -149,7 +149,7 @@ prometheus:
       env:
         QUERY_FLAGS: "--query.replica-label=monitor {% for h in groups['prometheus']|sort %} --store={{ h }}.prometheus.{{ domain }}:10901{% endfor %}"
         SIDECAR_FLAGS: ""
-        QUERY_FRONTEND_FLAGS: ""
+        QUERY_FRONTEND_FLAGS: "--query-range.response-cache-config-file=/etc/thanos/query-frontend-cache.yml"
       volumes:
         - /etc/thanos: /etc/thanos
     - name: karma

services.yml.no-elasticsearch

@@ -96,7 +96,7 @@ prometheus:
       env:
         QUERY_FLAGS: "--query.replica-label=monitor {% for h in groups['prometheus']|sort %} --store={{ h }}.prometheus.{{ domain }}:10901{% endfor %}"
         SIDECAR_FLAGS: ""
-        QUERY_FRONTEND_FLAGS: ""
+        QUERY_FRONTEND_FLAGS: "--query-range.response-cache-config-file=/etc/thanos/query-frontend-cache.yml"
       volumes:
         - /etc/thanos: /etc/thanos
     - name: karma