The implementation is agentless.
XorMon retrieves data from:

• The "ovirt_engine_history" database, which is part of the oVirt/RHV Virtualization Manager and contains only historical performance data
• The oVirt/RHV Virtualization Manager REST API (optional)
  Increases monitoring data set and enables Topology for oVirt, see REST API

OS Prerequisites

• Open network connection to the RedHat Virtualization Manager on port 5432
  
  
• Make sure you have installed perl modules: perl-DBI and perl-DBD-Pg on XorMon server
  Skip that on the Virtual Appliance
  

  # RedHat / Rocky Linux
  rpm -q perl-DBD-Pg
  perl-DBD-Pg-2.19.3-4.el7.x86_64
  
  # Debian / Ubuntu
  dpkg-query  -W libdbd-pg-perl
  libdbd-pg-perl	3.18.0-1.pgdg120+1

  Install them if they are missing under root user
  
  
  • Linux RedHat, CentOS

    yum install perl-DBD-Pg

  • Linux Debian, Ubuntu

    apt-get install libdbd-pg-perl

Database access

By default, only an administrator account is available in ovirt_engine_history.
Each Virtualization Manager has its own randomly generated password for ovirt_engine_history database.
To get the database password, you have to connect to your RHV / oVirt engine via SSH and run this command:

# grep DWH_DB_PASSWORD /etc/ovirt-engine-dwh/ovirt-engine-dwhd.conf.d/10-setup-database.conf

DB username should be 'ovirt_engine_history' by default, check it with this command:

# grep DWH_DB_USER /etc/ovirt-engine-dwh/ovirt-engine-dwhd.conf.d/10-setup-database.conf
ovirt_engine_history

It is also possible to create read-only user, but this requires configuring the database directly.
There is no tool for creating read-only users in the UI or CLI.

Creating a read-only user in the 'ovirt_engine_history' database

• Log in as root on the server where ovirt_engine_history is running
  (usually the oVirt Engine VM)
  
  
• Switch to the 'postgres' user
  

  su - postgres

• Connect to the database
  

  psql -d ovirt_engine_history

  You should see the following prompt:
  

  ovirt_engine_history=#

• Create a user 'xormon_ro'
  

  CREATE ROLE xormon_ro
      LOGIN
      NOSUPERUSER
      NOCREATEDB
      NOCREATEROLE
      NOREPLICATION;

• Set user password
  

  \password xormon_ro

• Configure database access
  

  GRANT CONNECT
  ON DATABASE ovirt_engine_history
  TO xormon_ro;
  
  GRANT USAGE
  ON SCHEMA public
  TO xormon_ro;
  
  GRANT SELECT
  ON ALL TABLES IN SCHEMA public
  TO xormon_ro;

• Get location of 'pg_hba.conf'
  This will be needed in a later step
  

  SHOW hba_file;

• Quit from psql
  

  \q

• Logout
  

  exit

• Allow access for 'xormon_ro' from XorMon appliance in 'pg_hba.conf'
  

  vi /var/lib/pgsql/data/pg_hba.conf

  Add the following line to the end of the file
  

  host    ovirt_engine_history    xormon_ro    <XorMon IP>/32    md5

  e.g.
  

  host    ovirt_engine_history    xormon_ro    192.168.1.12/32    md5

• Restart the database
  

  systemctl reload postgresql.service

REST API access

oVirt 4.5.1 and later include bundled Keycloak SSO.

Keycloak will be used only for user authentication.
Read-only permissions will be configured as a custom Admin role directly in oVirt Engine.

Creating a User in Keycloak

• Log in to the Keycloak management console
  
  https://<oVirt-engine-IP>/ovirt-engine-auth/admin
• Go to Manage -> Users, click Add user
• Set the username "xormon" and save
• Go to Credentials tab and set permanent password
No further configuration is required in Keycloak

Creating and Assigning a Role in the Administration Portal
• Log in to the oVirt Administration Portal
  
  https://<oVirt-engine-IP>/ovirt-engine/webadmin/
• Go to Administration -> Configure
• Select Roles and then New
  
  Name: "MonitoringReadOnly"
  Account Type: Admin
• Under Permissions, check only:
  
  System -> Configure System -> Login Permissions
  
  
• Go to Administration -> Configure
• Select System Permissions and click Add
  
  Search: internalsso
  User: xormon
  Role to assign: MonitoringReadOnly
  
  

XorMon storage configuration

• Add oVrit / RHV / OLVM from the UI:
  XorMon UI -> Settings icon -> Device ->; Server Virtualization -> RHV/oVirt -> New
  
  Enter the username for the REST API in the following format: "username@internalsso"
  In our case, "xormon@internalsso"
  
  
  
• Run "Test" for configured storage device, it must show "OK"
  
  
• If you get this error:

  FATAL: no pg_hba.conf entry for host XY user "ovirt_engine_history" database "ovirt_engine_history"ssl encryption", SSL off

  Add this line to pg_hba.conf on the oVirt database host:

  host  all  xormon  <monitoring machine IP/hostname>/32  <md5>/<scram-sha-256>

  Running this command on your DB can help you locate pg_hba.conf

  SHOW hba_file;

• Wait about 1 hour, then reload the web browser, you should see it in XorMon UI