diff --git a/agent/extra/testflinger-testenv/Dockerfile b/agent/extra/testflinger-testenv/Dockerfile
index d8012fccd..3a3e53d93 100644
--- a/agent/extra/testflinger-testenv/Dockerfile
+++ b/agent/extra/testflinger-testenv/Dockerfile
@@ -1,8 +1,8 @@
 ARG BASE_IMAGE=ubuntu:20.04
 FROM ${BASE_IMAGE}
-ENV container docker
+ENV container=docker
 RUN apt-get update && DEBIAN_FRONTEND=noninteractive apt-get install -y software-properties-common expect sudo openssh-client virtualenv curl wget build-essential python3-setuptools python3-dev python3-pip python3-requests python3-psutil git
-RUN adduser -u 1000 --disabled-password ubuntu
+RUN adduser -u 1000 --disabled-password ubuntu | /bin/true
 RUN echo "ubuntu ALL=(root) NOPASSWD:ALL" > /etc/sudoers.d/ubuntu && \
     chmod 0440 /etc/sudoers.d/ubuntu
 #Avoid sudo rlimit error