I had the same issue few months ago while using Linux self hosted agents. For that particular case, it turned up that there was a OS firmware update process running for my agent host that was killing the azdo agent process, as you can see in the journal logs:
fwupd[2844]: 18:47:15.266 FuMain Received SIGTERM
systemd[1]: Stopping fwupd.service - Firmware update daemon...
systemd[1]: Stopping multipathd.service - Device-Mapper Multipath Device Controller...
multipathd[198]: multipathd: shut down
systemd[1]: Stopping packagekit.service - PackageKit Daemon...
python3[904]: 2024-11-14T18:47:15.271871Z INFO Daemon Daemon Agent WALinuxAgent-2.9.1.1 forwarding signal 15 to WALinuxAgent-2.12.0.2
systemd[1]: Stopping walinuxagent.service - Azure Linux Agent...
systemd[1]: multipathd.service: Deactivated successfully.
systemd[1]: Stopped multipathd.service - Device-Mapper Multipath Device Controller.
systemd[1]: packagekit.service: Deactivated successfully.
systemd[1]: Stopped packagekit.service - PackageKit Daemon.
runuser[2772]: pam_unix(runuser:session): session closed for user AzDevOps
sudo[2769]: pam_unix(sudo:session): session closed for user root
systemd[1]: Starting multipathd.service - Device-Mapper Multipath Device Controller...
systemd[1]: Starting packagekit.service - PackageKit Daemon...
systemd[1]: fwupd.service: Deactivated successfully.
systemd[1]: Stopped fwupd.service - Firmware update daemon.
systemd[1]: fwupd.service: Consumed 1.013s CPU time, 143.6M memory peak, 0B memory swap peak.
PackageKit[5707]: daemon start
systemd[1]: Starting fwupd.service - Firmware update daemon...
multipathd[5710]: multipathd v0.9.4: start up
multipathd[5710]: reconfigure: setting up paths and maps
What solved the issue for us was turn off the service that performs that OS update and was triggering the SIGTERM for the AZDO agent:
sudo systemctl disable apt-daily.timer
sudo systemctl disable apt-daily-upgrade.timer
sudo systemctl stop apt-daily.timer
sudo systemctl stop apt-daily-upgrade.timer
You can find more info at the github issue related: https://github.com/microsoft/azure-pipelines-agent/issues/4313#issuecomment-2501564255