gateway: fix crash on ipv4 only systems (#11722)

**What this PR does / why we need it**: Loki Gateway pod crashes on
systems that only have IPv4 enabled since PR
#9510

**Which issue(s) this PR fixes**:
Fixes #9681

**Special notes for your reviewer**:

**Checklist**
- [x] Reviewed the
[`CONTRIBUTING.md`](https://github.com/grafana/loki/blob/main/CONTRIBUTING.md)
guide (**required**)
- [x] Documentation added
- [ ] Tests updated
- [x] `CHANGELOG.md` updated
- [x] If the change is worth mentioning in the release notes, add
`add-to-release-notes` label
- [x] Changes that require user attention or interaction to upgrade are
documented in `docs/sources/setup/upgrade/_index.md`
- [x] For Helm chart changes bump the Helm chart version in
`production/helm/loki/Chart.yaml` and update
`production/helm/loki/CHANGELOG.md` and
`production/helm/loki/README.md`. [Example
PR](d10549e)
- [x] If the change is deprecating or removing a configuration option,
update the `deprecated-config.yaml` and `deleted-config.yaml` files
respectively in the `tools/deprecated-config-checker` directory.
[Example
PR](0d4416a)

---------

Signed-off-by: Pieter van der Giessen <[email protected]>
Co-authored-by: Michel Hollands <[email protected]>

docs/sources/setup/install/helm/reference.md

@@ -1242,6 +1242,15 @@ null
 			<td><pre lang="json">
 null
 </pre>
+</td>
+		</tr>
+		<tr>
+			<td>gateway.nginxConfig.enableIPv6</td>
+			<td>bool</td>
+			<td>Enable listener for IPv6, disable on IPv4-only systems</td>
+			<td><pre lang="json">
+true
+</pre>
 </td>
 		</tr>
 		<tr>

production/helm/loki/CHANGELOG.md

@@ -14,6 +14,10 @@ Entries should include a reference to the pull request that introduced the chang
 [//]: # (<AUTOMATED_UPDATES_LOCATOR> : do not remove this line. This locator is used by the CI pipeline to automatically create a changelog entry for each new Loki release. Add other chart versions and respective changelog entries bellow this line.)
 
 
+## 5.41.8
+
+- [BUGFIX] Fix gateway: add possibility to disable listening on ipv6 to prevent crash on ipv4-only system.
+
 ## 5.41.7
 
 - [FEATURE] Add support to disable specific alert rules

production/helm/loki/Chart.yaml

@@ -3,7 +3,7 @@ name: loki
 description: Helm chart for Grafana Loki in simple, scalable mode
 type: application
 appVersion: 2.9.3
-version: 5.41.7
+version: 5.41.8
 home: https://grafana.github.io/helm-charts
 sources:
   - https://github.com/grafana/loki

production/helm/loki/README.md

@@ -1,6 +1,6 @@
 # loki
 
-![Version: 5.41.7](https://img.shields.io/badge/Version-5.41.7-informational?style=flat-square) ![Type: application](https://img.shields.io/badge/Type-application-informational?style=flat-square) ![AppVersion: 2.9.3](https://img.shields.io/badge/AppVersion-2.9.3-informational?style=flat-square)
+![Version: 5.41.8](https://img.shields.io/badge/Version-5.41.8-informational?style=flat-square) ![Type: application](https://img.shields.io/badge/Type-application-informational?style=flat-square) ![AppVersion: 2.9.3](https://img.shields.io/badge/AppVersion-2.9.3-informational?style=flat-square)
 
 Helm chart for Grafana Loki in simple, scalable mode
 

production/helm/loki/templates/_helpers.tpl

@@ -695,7 +695,9 @@ http {
 
   server {
     listen             8080;
+    {{- if .Values.gateway.nginxConfig.enableIPv6 }}
     listen             [::]:8080;
+    {{- end }}
 
     {{- if .Values.gateway.basicAuth.enabled }}
     auth_basic           "Loki";

production/helm/loki/values.yaml

@@ -1448,6 +1448,8 @@ gateway:
     initialDelaySeconds: 15
     timeoutSeconds: 1
   nginxConfig:
+    # -- Enable listener for IPv6, disable on IPv4-only systems
+    enableIPv6: true
     # -- NGINX log format
     logFormat: |-
       main '$remote_addr - $remote_user [$time_local]  $status '