How to system test with fixed time on Fargate

How do you perform system tests with fixed time on Fargate?

I considered logging into the container using the aws ecs execute-command and changing the time using the date command, but since privileged containers aren't supported on Fargate I get the following error occurred and I was unable to change it.

date: cannot set date: Operation not permitted

However, you can adjust the system time by using libfaketime. Although the version is old, the Dockerfile verified with Keycloak 19.0.2 image　is shown below.

FROM quay.io/keycloak/keycloak:19.0.2 AS builder

USER root

RUN microdnf install -y git make gcc
RUN git clone https://github.com/wolfcw/libfaketime.git
WORKDIR /libfaketime/src
RUN make install
ENV LD_PRELOAD=/usr/local/lib/faketime/libfaketime.so.1

ENV FAKETIME="2025-04-24 10:30:00"
RUN date

WORKDIR /opt/keycloak

ENTRYPOINT [ "/opt/keycloak/bin/kc.sh" ]

If you enter the container and execute the date command as shown below, you will see that the value specified by the FAKETIME variable is fixed.

% aws ecs execute-command --cluster _clustername_ --task _taskID_ --interactive --command "/bin/bash"

The Session Manager plugin was installed successfully. Use the AWS CLI to start a session.

Starting session with SessionId: ecs-execute-command-xxxxxxxxx
[root@ip-NNN-NNN-NNN-NNN keycloak]# date
Thu Apr 24 10:30:00 UTC 2025

Please try it yourself.