From 6cdf15e7b9236bb264829f79ae626f8bf36b92ed Mon Sep 17 00:00:00 2001
From: "loki-gh-app[bot]" <160051081+loki-gh-app[bot]@users.noreply.github.com>
Date: Wed, 13 Nov 2024 14:14:47 +0000
Subject: [PATCH] chore: add flag to disable pod constraints to querier configs
 (backport k228) (#14895)

Co-authored-by: Poyzan <31743851+poyzannur@users.noreply.github.com>
---
 production/ksonnet/loki/config.libsonnet  | 4 ++++
 production/ksonnet/loki/querier.libsonnet | 5 ++++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/production/ksonnet/loki/config.libsonnet b/production/ksonnet/loki/config.libsonnet
index bd7a52e53d8ea..b4e7f1d2abe57 100644
--- a/production/ksonnet/loki/config.libsonnet
+++ b/production/ksonnet/loki/config.libsonnet
@@ -52,6 +52,10 @@
       // cores and will result in scheduling delays.
       concurrency: 4,
 
+      // use_no_constraints is false by default allowing either TopologySpreadConstraints or pod antiAffinity to be configured.
+      // If no_schedule_constraints is set to true, neither of the pod constraints will be applied.
+      no_schedule_constraints: false,
+
       // If use_topology_spread is true, queriers can run on nodes already running queriers but will be
       // spread through the available nodes using a TopologySpreadConstraints with a max skew
       // of topology_spread_max_skew.
diff --git a/production/ksonnet/loki/querier.libsonnet b/production/ksonnet/loki/querier.libsonnet
index 8cc965d777d6a..c6afbe3e85b4c 100644
--- a/production/ksonnet/loki/querier.libsonnet
+++ b/production/ksonnet/loki/querier.libsonnet
@@ -29,6 +29,7 @@ local k = import 'ksonnet-util/kausal.libsonnet';
   local topologySpreadConstraints = k.core.v1.topologySpreadConstraint,
 
   querier_deployment: if !$._config.stateful_queriers then
+    assert !($._config.querier.no_schedule_constraints && $._config.querier.use_topology_spread) : 'Must configure either no_schedule_constraints or TopologySpreadConstraints, but not both';
     deployment.new('querier', 3, [$.querier_container]) +
     $.config_hash_mixin +
     k.util.configVolumeMount('loki', '/etc/loki/config') +
@@ -38,7 +39,8 @@ local k = import 'ksonnet-util/kausal.libsonnet';
     ) +
     deployment.mixin.spec.strategy.rollingUpdate.withMaxSurge('15%') +
     deployment.mixin.spec.strategy.rollingUpdate.withMaxUnavailable('15%') +
-    if $._config.querier.use_topology_spread then
+    if $._config.querier.no_schedule_constraints then {}
+    else if $._config.querier.use_topology_spread then
       deployment.spec.template.spec.withTopologySpreadConstraints(
         // Evenly spread queriers among available nodes.
         topologySpreadConstraints.labelSelector.withMatchLabels({ name: 'querier' }) +
@@ -50,6 +52,7 @@ local k = import 'ksonnet-util/kausal.libsonnet';
       k.util.antiAffinity
   else {},
 
+
   // PVC for queriers when running as statefulsets
   querier_data_pvc:: if $._config.stateful_queriers then
     pvc.new('querier-data') +