diff --git a/ansible/roles/prometheus/tasks/config.yml b/ansible/roles/prometheus/tasks/config.yml
index df8b030bec..0754d714dd 100644
--- a/ansible/roles/prometheus/tasks/config.yml
+++ b/ansible/roles/prometheus/tasks/config.yml
@@ -71,8 +71,8 @@
   become: true
   vars:
     service: "{{ prometheus_services['prometheus-server'] }}"
-    common_overrides: "{{ prometheus_common_config_overrides_result.files | map(attribute='path') | list }}"
-    host_overrides: "{{ prometheus_host_config_overrides_result.files | map(attribute='path') | list }}"
+    common_overrides: "{{ prometheus_common_config_overrides_result.files | map(attribute='path') | list | sort }}"
+    host_overrides: "{{ prometheus_host_config_overrides_result.files | map(attribute='path') | list | sort }}"
   merge_yaml:
     sources: "{{ [item] + common_overrides + host_overrides }}"
     dest: "{{ node_config_directory }}/prometheus-server/prometheus.yml"
diff --git a/releasenotes/notes/bug-2126635-794d6e351dc6fc2c.yaml b/releasenotes/notes/bug-2126635-794d6e351dc6fc2c.yaml
new file mode 100644
index 0000000000..344266a214
--- /dev/null
+++ b/releasenotes/notes/bug-2126635-794d6e351dc6fc2c.yaml
@@ -0,0 +1,11 @@
+---
+fixes:
+  - |
+    Make generation of prometheus.yml consistent when using custom override
+    files.
+
+    Previous behaviour would lead to changes in prometheus.yml on every run
+    when custom override files were used, as the find result was not sorted.
+    This could lead to unnecessary restarts and unreadable diffs of the
+    prometheus service.
+    `LP#2126635 <https://launchpad.net/bugs/2126635>`__