diff --git a/ansible/roles/postgresql_server/tasks/main.yml b/ansible/roles/postgresql_server/tasks/main.yml
index d5a1c1d..bcea0d8 100644
--- a/ansible/roles/postgresql_server/tasks/main.yml
+++ b/ansible/roles/postgresql_server/tasks/main.yml
@@ -56,7 +56,7 @@
   - postgresql
 
 - name: Set kernel shared memory max to a larger value
-  sysctl: name=kernel.shmmax value={{ kernel_shmmax }}
+  sysctl: name=kernel.shmmax value="{{ kernel_shmmax }}"
   when: kernel_shmmax is defined
   notify:
   - restart postgresql