diff --git a/coreos-config/runner-pre.yaml b/coreos-config/runner-pre.yaml
index 23d8253..9af7f65 100644
--- a/coreos-config/runner-pre.yaml
+++ b/coreos-config/runner-pre.yaml
@@ -11,6 +11,7 @@
         path: /etc/hosts
         regexp: "^{{ item }}\\s"
         line: "{{ hostvars[item]['wg_addr'] | mandatory }} {{ item }}"
+        unsafe_writes: true # Docker does not allow atomic updates here.
         state: present
       loop: "{{ groups['all'] }}"