wiki/Web-app-general.md

Setup of web server

Two instances of the photodiag-web server are hosted on the sf-phmon-01.psi.ch virtual machine, both accessible only from the beamline networks/control rooms:

• Production server: https://sf-photodiag.psi.ch
• Test server: https://sf-photodiag-test.psi.ch

Server updates

• The service repository is hosted at: https://gitlab.psi.ch/photon-diagnostics/photodiag_web
• Pushing a commit on the main branch updates the test server.
• Pushing a tagged commit on the main branch updates both the test and production servers.

To push a release to the main server:

1. Pull the latest tested and operational version:

   git pull

2. Create a new release (choose one of patch, minor, or major):

   python make_release.py patch

3. Push the new tag(s):

   git push origin main --tags

You can check the release status via GitLab CI/CD pipelines.

Server logs

When logged into either sf-phmon-01 or sf-phmon-02, you can view logs with:

sudo journalctl -u photodiag-<test|prod> -e

Replace <test|prod> with the desired instance.

For example, to see the last 100 lines of logs on sf-phmon-02:

ssh sf-phmon-02
sudo -i
journalctl -u photodiag-test.service -n 100

Restarting the VM or the service

1. Restart the entire VM:

   sudo reboot
   

2. Restart a single service (for example, photodiag test or prod):

   sudo systemctl restart <service_name>.service
   

Replace <service_name> with photodiag-test or photodiag-prod.

Server Monitoring

To monitor the status and performance of the photodiag-web servers, you can access real-time server statistics via Grafana. These dashboards show CPU usage, memory consumption, network traffic, and disk I/O, which can help diagnose performance issues.

Server Status Links

• sf-phmon-01: Grafana Metrics - sf-phmon-01
• sf-phmon-02: Grafana Metrics - sf-phmon-02

Available Metrics

The Grafana dashboards provide the following system performance data:

• CPU Usage: Tracks system, user, idle, and I/O wait time.
• Memory Usage: Displays total and used memory statistics.
• Network Traffic: Monitors inbound and outbound data transfer rates.
• Disk I/O: Reports read/write operations per second.