diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 45332347fd56d1f809fef2079af45fea318b47b5..4b5dddb04e2f7033220009f783b91e5c4a5052ca 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -1,4 +1,4 @@
-image: golang:1.21.9-alpine3.19
+image: golang:1.21.9-alpine3.19@sha256:ed8ce6c22dd111631c062218989d17ab4b46b503cbe9a9cfce1517836e65298a
 
 before_script:
   - echo ':before_script'
@@ -21,8 +21,8 @@ include:
 test:
   stage: test
   services:
-    - docker:dind
-    - postgres:14.1
+    - docker:dind@sha256:3ab005a2e4872f0b10fb9c00d4230334043f1281f29299bd3de94a8f14a05e69
+    - postgres:14.1@sha256:3162a6ead070474b27289f09eac4c865e75f93847a2d7098f718ee5a721637c4
   variables:
     # Improve performance with overlayfs.
     DOCKER_DRIVER: overlay2