diff --git a/gitlab-ci/docker/jessie/Dockerfile b/gitlab-ci/docker/jessie/Dockerfile
index 2a3a4b884ac3b027369be4bd20c46005f4e4897a..fe5da85bcb90bb9ef613a3a181f4359ab59befc2 100644
--- a/gitlab-ci/docker/jessie/Dockerfile
+++ b/gitlab-ci/docker/jessie/Dockerfile
@@ -1,13 +1,12 @@
 FROM debian:jessie-slim
 
-RUN apt-get update
-RUN apt-get upgrade -y
-
 # Minimal tools required by acme-dns-tiny CI
-RUN apt-get install -y --no-install-recommends \
-	python3-dnspython \
-	python3-coverage \
-	python3-pip
+RUN apt-get update \
+	&& apt-get install -y --no-install-recommends \
+		python3-dnspython \
+		python3-coverage \
+		python3-pip \
+	&& apt-get clean
 
 # Allows run python3-coverage with same command than manual install by pip
 RUN update-alternatives --install \
diff --git a/gitlab-ci/docker/stretch/Dockerfile b/gitlab-ci/docker/stretch/Dockerfile
index 34ddbe83d0cdde5917d8b9dc1d1ede4422664737..04729c890b987350a6bc35fdcad74bdfdfbcbc2b 100644
--- a/gitlab-ci/docker/stretch/Dockerfile
+++ b/gitlab-ci/docker/stretch/Dockerfile
@@ -1,14 +1,12 @@
 FROM debian:stretch-slim
 
-RUN apt-get update
-RUN apt-get upgrade -y
-
 # Minimal tools required by acme-dns-tiny CI
-RUN apt-get install -y --no-install-recommends \
-	python3-dnspython \
-	python3-coverage \
-	python3-configargparse \
-	python3-pip
+RUN apt-get update \
+	&& apt-get install -y --no-install-recommends \
+		python3-dnspython \
+		python3-coverage \
+		python3-configargparse \
+		python3-pip
 
 # Allows run python3-coverage with same command than manual install by pip
 RUN update-alternatives --install \
diff --git a/gitlab-ci/gitlab-ci.yml b/gitlab-ci/gitlab-ci.yml
index f26351d9448d5ccefbcf1ca47fb44085bbb272ef..482513bc78666cea91a639d46aaea3c0259ec5cd 100644
--- a/gitlab-ci/gitlab-ci.yml
+++ b/gitlab-ci/gitlab-ci.yml
@@ -1,5 +1,6 @@
 jessie:
-  image: adt-jessie
+  tags:
+    - jessie
   before_script:
     - pip3 install --upgrade -r tests/requirements.txt
   script:
@@ -8,7 +9,8 @@ jessie:
     - coverage html
 
 stretch:
-  image: adt-stretch
+  tags:
+    - stretch
   before_script:
     - pip3 install --upgrade -r tests/requirements.txt
   script: