diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index f568e196ea45d238163083f4c0940837abcde3ab..d0d6c0433df01c2a1bbb2094511c892734035890 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -34,7 +34,7 @@ generate-reference-api:
     - grid5000-docker
    image: debian:stretch
    script:
-    - apt-get update && apt-get -y install ruby rake ruby-hashdiff git
+    - apt-get update && apt-get -y install ruby rake ruby-hashdiff git ruby-ipaddress
     - gem install hash_validator
     - export TZ=Europe/Paris
     - rake reference-api