diff --git a/roles/container-engine/docker/tasks/set_facts_dns.yml b/roles/container-engine/docker/tasks/set_facts_dns.yml
index 42a2c64bc..673811972 100644
--- a/roles/container-engine/docker/tasks/set_facts_dns.yml
+++ b/roles/container-engine/docker/tasks/set_facts_dns.yml
@@ -38,12 +38,12 @@
 - name: Add system nameservers to docker options
   set_fact:
     docker_dns_servers: "{{ docker_dns_servers | union(system_nameservers.stdout_lines) | unique }}"
-  when: system_nameservers.stdout
+  when: system_nameservers.stdout != ""
 
 - name: Add system search domains to docker options
   set_fact:
     docker_dns_search_domains: "{{ docker_dns_search_domains | union(system_search_domains.stdout.split() | default([])) | unique }}"
-  when: system_search_domains.stdout
+  when: system_search_domains.stdout != ""
 
 - name: Check number of nameservers
   fail: