diff --git a/testenv/docker/krb5kdc-latest/Dockerfile b/testenv/docker/krb5kdc-latest/Dockerfile
index 80b6537..8d24bfc 100644
--- a/testenv/docker/krb5kdc-latest/Dockerfile
+++ b/testenv/docker/krb5kdc-latest/Dockerfile
@@ -1,4 +1,4 @@
-FROM centos:latest
+FROM centos:7
 
 EXPOSE 88
 
diff --git a/testenv/docker/krb5kdc-older/Dockerfile b/testenv/docker/krb5kdc-older/Dockerfile
index 0bbb3b7..f7e311d 100644
--- a/testenv/docker/krb5kdc-older/Dockerfile
+++ b/testenv/docker/krb5kdc-older/Dockerfile
@@ -1,4 +1,4 @@
-FROM centos:latest
+FROM centos:7
 
 EXPOSE 88
 
diff --git a/testenv/docker/krb5kdc-res/Dockerfile b/testenv/docker/krb5kdc-res/Dockerfile
index f25f53a..45c3132 100644
--- a/testenv/docker/krb5kdc-res/Dockerfile
+++ b/testenv/docker/krb5kdc-res/Dockerfile
@@ -1,4 +1,4 @@
-FROM centos:latest
+FROM centos:7
 
 EXPOSE 88
 ENTRYPOINT ["/usr/sbin/krb5kdc", "-n"]
diff --git a/testenv/docker/krb5kdc-shorttickets/Dockerfile b/testenv/docker/krb5kdc-shorttickets/Dockerfile
index 4d121a4..eed5a28 100644
--- a/testenv/docker/krb5kdc-shorttickets/Dockerfile
+++ b/testenv/docker/krb5kdc-shorttickets/Dockerfile
@@ -1,4 +1,4 @@
-FROM centos:latest
+FROM centos:7
 
 EXPOSE 88
 EXPOSE 464
diff --git a/testenv/docker/krb5kdc-sub/Dockerfile b/testenv/docker/krb5kdc-sub/Dockerfile
index cb7d4c8..e6aa9ca 100644
--- a/testenv/docker/krb5kdc-sub/Dockerfile
+++ b/testenv/docker/krb5kdc-sub/Dockerfile
@@ -1,4 +1,4 @@
-FROM centos:latest
+FROM centos:7
 
 EXPOSE 88
 ENTRYPOINT ["/usr/sbin/krb5kdc", "-n"]
diff --git a/testenv/docker/krb5kdc/Dockerfile b/testenv/docker/krb5kdc/Dockerfile
index 4d121a4..eed5a28 100644
--- a/testenv/docker/krb5kdc/Dockerfile
+++ b/testenv/docker/krb5kdc/Dockerfile
@@ -1,4 +1,4 @@
-FROM centos:latest
+FROM centos:7
 
 EXPOSE 88
 EXPOSE 464