RT Container Test Framework

The RT Container Test Framework is designed to validate runtime stability and deterministic execution behavior of containers running on a Linux PREEMPT_RT patched kernel.

This framework enables:

• Validation of container runtime behavior in RT environments
• Repeated execution stability testing
• Comparative testing between Docker and Podman

---

1. System Requirements

1.1 PREEMPT_RT Kernel (Mandatory)

A Linux kernel patched with PREEMPT_RT is required for meaningful real-time performance validation.

Verify RT Kernel

uname -a

Expected output should include:

PREEMPT_RT

If the RT flag is not present, the real-time test results will not be valid.

Raspberry Pi RT Kernel

If you need an RT kernel image for Raspberry Pi, refer to:

https://github.com/ros-realtime/ros-realtime-rpi4-image

---

1.2 CPU Isolation (Recommended)

CPU isolation improves test reliability by reducing interference from system processes.

Ubuntu

Edit GRUB configuration:

sudo vi /etc/default/grub

Modify the following line:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash threadirqs isolcpus=3 nohz_full=3 rcu_nocbs=3 irqaffinity=0-2"

Apply changes:

sudo update-grub
sudo reboot

---

Raspberry Pi

1️⃣ Update Kernel Parameters

sudo vi /boot/firmware/cmdline.txt

console=serial0,115200 dwc_otg.lpm_enable=0 console=tty1 root=LABEL=writable rootfstype=ext4 rootwait fixrtc quiet splash isolcpus=3 nohz_full=3 rcu_nocbs=3 irqaffinity=0-2 threadirqs

2️⃣ Configure RT Priority

sudo vi /etc/security/limits.d/20-ubuntu-rt.conf

*  -  rtprio  99
*  -  memlock unlimited

---

1.3 Container Engine

At least one container engine must be installed:

• Docker
• Podman

Verify installation:

docker --version

or

podman --version

---

2. Project Structure

host
container
├── dockerfiles
│   └── rt_test
│       └── Dockerfile.rt_test
├── scripts
│   ├── env
│   │   └── env_build.sh
│   ├── run.sh
│   ├── setup
│   │   ├── docker.sh
│   │   └── podman.sh
│   └── test
│       ├── entry
│       │   └── rt_test.sh
│       └── test.sh
└── test.sh

---

3. Usage

3.1 Multi-Engine Repeated Test (Recommended)

./test.sh <test-count> <engine1> <engine2> ...

Example

./test.sh 3 docker podman

Meaning:

• Run 3 iterations per engine
• Execute tests for Docker and Podman

---

Internal Command Execution

./scripts/run.sh <engine> rt_test ./dockerfiles/rt_test <result-dir> <cyclic-test-loop-count> rt_test.sh [cpu-list]

---

Parameters

Parameter	Description
engine	docker or podman
image-name	Container image name
dockerfile-path	Path to Dockerfile directory
result-path	Directory for storing results
loop	Number of internal RT test iterations
test_script	Script executed inside the container

---

4. Output

Test results are stored per engine:

~/rt/test/container/results/docker/
~/rt/test/container/results/podman/