The main purpose of this package is allow users to setup an environment which prevents applications and container tools from interfering with other processes on the system. For example ASIL (Automotive Safety Integrity Level) environments.
The QM environment uses containerization tools like cgroups, namespaces, and security isolation to prevent accidental interference by processes in the qm.
The QM will run its own version of systemd and Podman to isolate not only the applications and containers launched by systemd and Podman but systemd and Podman commands themselves.
This package requires the Podman package to establish the containerized environment and uses quadlet to set it up.
Software install into the qm environment under /usr/lib/qm/rootfs will be automatically isolated from the host. But if developers want to further isolate these processes from other processes in the QM they can use container tools like Podman to further isolate.
- SELinux Policy
This policy is used to isolate Quality Management parts of the operating system from the other Domain-Specific Functional Safety Levels (ASIL).
The main purpose of this policy is to prevent applications and container tools with interfering with other processes on the system. The QM needs to support further isolate containers run within the qm from the qm_t process and from each other.
For now all of the control processes in the qm other then containers will run with the same qm_t type.
Still would like to discuss about a specific selinux prevision? Please open an QM issue with the output of selinux error from a recent operation related to QM. The output of the following commands are appreciated for understanding the root cause.
ausearch -m avc -ts recent | audit2why
journalctl -t setroubleshoot
sealert -a /var/log/audit/audit.logThe package configures the bluechi agent within the QM.
BlueChi is a systemd service controller intended for multi-node environments with a predefined number of nodes and with a focus on highly regulated ecosystems such as those requiring functional safety. Potential use cases can be found in domains such as transportation, where services need to be controlled across different edge devices and where traditional orchestration tools are not compliant with regulatory requirements.
Systems with QM installed will have two systemd's running on them. The QM bluechi-agent is based on the hosts /etc/bluechi/agent.conf file. By default any changes to the systems agent.conf file are reflected into the QM /etc/bluechi/agent.conf. You can further customize the QM bluechi agent by adding content to the /usr/lib/qm/rootfs/etc/bluechi/agent.conf.d/ directory.
In order to build qm package on CentOS Stream 9 you'll need Code Ready Builder
repository enabled in order to provide golang-github-cpuguy83-md2man package.
# dnf install -y python3-dnf-plugins-core
# dnf config-manager --set-enabled crbThe om_score_adj refers to the "Out of Memory score adjustment" in Linux operating systems. This parameter is used by the Out of Memory (OOM) killer to decide which processes to terminate when the system is critically low on memory.
By fine-tuning which processes are more likely to be terminated during low memory situations, critical processes can be protected, thereby enhancing the overall stability of the system. For instance only, ASIL (Automotive Safety Integrity Level) applications, which are critical for ensuring functional safety in automotive systems, will be preserved in case of low resources.
- All nested containers created inside QM will have their OOM score adjustment set to 750.
$ cat /usr/share/qm/containers.conf | grep oom_score_adj
oom_score_adj = 750- The QM process has a default OOM score adjustment value set to 500, configured via the qm.container file.
cat /usr/share/containers/systemd/qm.container | grep OOMScoreAdjust
# OOMScoreAdjust=500If we consider the example of ASIL (Automotive Safety Integrity Level) applications, which are essential for maintaining functional safety in automotive systems, their OOM score adjustment values can range from -1 to -1000. Setting the value to -1000 makes the process immune to the OOM killer. This ensures that ASIL applications are the last to be terminated by the OOM killer, thus prioritizing their operation even in low memory situations.
- Nested Containers inside QM: OOM score adjustment set to 750. (/usr/share/qm/containers.conf)
- QM Process: OOM score adjustment value set to 500, configured via the qm.container file.
- ASIL Applications: Can explore a range from -1 to -1000, with -1000 making the process immune to the OOM killer.
+-------------------------------------------------------------+
| The Priority Process of OOM Killer in the QM Context |
+-------------------------------------------------------------+
------------------------------------ Kernel space -----------------------------------------------
+--------------------------------+
| Out of Memory Killer Mechanism |
| (OOM Killer) |
+--------------------------------+
|
v
+--------------------------------+
| Kernel Scheduler |
+--------------------------------+
------------------------------------ User space -------------------------------------------------
+----------------------------------------+
| Out of Memory Score Adjustment |
| (oom_score_adj) |
+----------------------------------------+
|
|
v (Processes Priority side by side)
+-----------------------------+--------------------------+-----------------------+
| | | |
v v v v
+------------------+ +----------------------------+ +-----------------+ +-----------------+
| | | | | | | |
| QM Container | | Nested Containers by QM | | ASIL Apps | | Other Processes |
| | | | | | | |
| OOM Score | | OOM Score | | OOM Score | | OOM Score |
| 500 | | 750 | | -1 to -1000 | | (default: 0) |
+------------------+ +----------------------------+ +-----------------+ +-----------------+
| | | |
v v v v
+----------------+ +----------------+ +--------------------+ +-----------------+
| Lower priority | | Higher priority| | Very low priority | | Default priority|
| for termination| | for termination| | for termination | | for termination |
+----------------+ +----------------+ +--------------------+ +-----------------+
|
|
|
v
+-------------------------------------------------------------+
| |
| In conclusion, all nested containers created inside QM have |
| their OOM score adjustment set to 750, making them more |
| likely to be terminated first compared to the QM process. |
| |
| When compared to ASIL applications, nested containers |
| will have an even higher likelihood of being terminated. |
| |
| Compared to other processes with the default adjustment |
| value of 0, nested containers are still more likely to be |
| terminated first, ensuring the system and ASIL Apps are |
| kept as safe as possible. |
| |
+-------------------------------------------------------------+
------------------------------------ User space -------------------------------------------------
------------------------------------ Kernel space -----------------------------------------------Looking for quadlet examples files? See our docs dir.
If your looking for contribute to the project use our development README guide as start point.
Looking for a specific version of QM? Search in the mirrors list below.