Advanced Monitoring does not work: Panel plugin not found: graph

Symptoms

• Graphs are not displayed in Advanced Monitoring, but the following error is shown:

  Panel plugin not found: graph

  ---

  The plesk-json-backend-datasource plugin is not installed

• The following messages can be found in /var/log/grafana/grafana.log:

  lvl=eror msg="Request Completed" logger=context userId=0 orgId=0 uname= method=GET path=/login/generic_oauth status=500 remote_addr=127.0.0.1 time_ms=0 size=1766 referer="https://203.0.113.2:8443/modules/monitoring/index.php/index/main?context=extNavButton_monitoring_1"

  and

  lvl=eror msg="Failed to save invalid login attempt" logger=login err="attempt to write a readonly database"
  lvl=eror msg="Invalid username or password" logger=context error="Invalid Username or Password"

• The following warning can be found in /var/log/plesk/panel.log when accessing Advanced Monitoring with debug mode enabled:

  WARN [extension/grafana] Dashboard update failed. ID: monitoring__network. Error: Invalid username or password

Cause

Corrupted Grafana installation.

Resolution

1. Connect to the server via SSH

2. Remove the Grafana extension:

   # plesk bin extension --uninstall grafana

3. Remove the Advanced Monitoring extension:

   # plesk bin extension --uninstall monitoring

4. Remove Grafana from the server:

   • For Debian or Ubuntu operating systems:

     # apt purge grafana && rm -rf /usr/share/grafana /etc/grafana /var/lib/grafana

   • For RHEL, CentOS or CloudLinux operating systems:

     # yum remove grafana && rm -rf /usr/share/grafana /etc/grafana /var/lib/grafana

5. Reinstall the Grafana extension:

   # plesk bin extension --install grafana

   # plesk bin extension --install monitoring

6. If the following error message is shown at Advanced Monitoring, press Fix installation button: