Installation and Configuration

This section explains how to install and configure a new Horizon instance.

Objectives

Install all required OpenNMS Horizon components, including PostgreSQL, on a single node.
Run Horizon core and PostgreSQL with the default configuration.

The default configuration is not optimized to run in production or monitor large networks.
- By default, your time series database is JRobin, which persists RRD files on the local file system.
Log in to the web UI and change the admin account’s default password.

Requirements

A Linux physical server or a virtual machine running a supported Linux operating system.
Internet access to download the installation packages.
A working DNS server, and a localhost and server name that resolve properly.
A system user with administrative permissions (sudo) to perform installation.
A SELinux policy that permits binding to the ICMP service (if you are using an operating system that includes SELinux).

Note that failure to include the appropriate SELinux policy may generate an ICMP permission error when starting OpenNMS (see SELinux and ICMP permissions).
To run services in Docker, you need Docker Compose for the service stacks from our examples.

On Debian, you must install and configure sudo yourself. See the Debian Wiki for more information.

Time synchronization is a critical part of operating a monitoring system. Ensure you have a functional time synchronization process running with your operating system. If you are not familiar with this topic, the knowledgebase article Ensure time synchronization for your OpenNMS components is a good starting point.

SELinux and ICMP permissions

If you have SELinux enabled on your Horizon server, there must be a policy configured to allow Horizon to bind to the ICMP service.

The steps in this section apply specifically to CentOS 8.

To verify that you have SELinux running and enabled, use the sestatus console command. If it is enabled, you should see the following:

SELinux status:                 enabled
SELinuxfs mount:                /sys/fs/selinux
SELinux root directory:         /etc/selinux
Loaded policy name:             targeted
Current mode:                   enforcing
Mode from config file:          enforcing
Policy MLS status:              enabled
Policy deny_unknown status:     allowed
Memory protection checking:     actual (secure)
Max kernel policy version:      33

Use audit2allow -a to check if Horizon violates SELinux policies.

If the audit2allow command is missing, run dnf install policycoreutils-devel to install the package.

Look for entries that prevent the binding of ICMP sockets:

#============= unconfined_service_t ==============
allow unconfined_service_t node_t:icmp_socket node_bind;

============= unconfined_service_t ==============
allow unconfined_service_t port_t:icmp_socket name_bind;

Create a type enforcement file (for example, JniPing.te):

module JniPing 1.0;

require {
        type unconfined_service_t;
        type node_t;
        type port_t;
        class icmp_socket { name_bind node_bind };
}

#============= unconfined_service_t ==============
allow unconfined_service_t node_t:icmp_socket node_bind;
allow unconfined_service_t port_t:icmp_socket name_bind;

Create a SElinux module and compile it:

checkmodule -M -m -o JniPing.mod JniPing.te
semodule_package -o JniPing.pp -m JniPing.mod

Install the SELinux package and enforce it:

semodule -i JniPing.pp
getenforce

You can verify the package with the following command: semodule --list-modules | grep JniPing.

Note that this command is based on the audit2allow command on a CentOS 8 system.

Set up PostgreSQL

PostgreSQL 14 and 15 use the scram-sha-256 password authentication method by default. If you use older versions of PostgreSQL, you should change the method in postgresql.conf and in pg_hba.conf before continuing with the core instance installation.

CentOS/RHEL 9
CentOS/RHEL 8
CentOS/RHEL 7
Debian/Ubuntu
Docker

Install language packs and set language

sudo dnf install langpacks-en glibc-all-langpacks -y
sudo localectl set-locale LANG=en_US.UTF-8
sudo localectl
sudo dnf makecache
sudo dnf update -y
sudo reboot
sudo dnf info postgresql-server

These procedures use a specific PostgreSQL version. Make sure you reference your current PostgreSQL version.

Install PostgreSQL client and server

sudo dnf -y install https://download.postgresql.org/pub/repos/yum/reporpms/EL-9-x86_64/pgdg-redhat-repo-latest.noarch.rpm
sudo dnf -y install postgresql14-server

Initialize the PostgreSQL database

sudo /usr/pgsql-14/bin/postgresql-14-setup initdb

Enable PostgreSQL on system boot and start immediately

sudo systemctl enable --now postgresql-14

Create an opennms database user and password

sudo -i -u postgres createuser -P opennms

You must provide a secure password for the opennms database user account. This guide uses YOUR-OPENNMS-PASSWORD as a placeholder.

Create an empty database and set the owner to the opennms user

sudo -i -u postgres createdb -O opennms opennms

Set a password for PostgreSQL superuser

sudo -i -u postgres psql -c "ALTER USER postgres WITH PASSWORD 'YOUR-POSTGRES-PASSWORD';"

Change YOUR-POSTGRES-PASSWORD to a secure one. The superuser is required to be able to initialize and change the database schema for installation and updates.

Change the access policy for PostgreSQL

sudo vi /var/lib/pgsql/14/data/pg_hba.conf

Allow Horizon to access the database over the local network with an MD5 hashed password

host    all             all             127.0.0.1/32            md5 (1)
host    all             all             ::1/128                 md5 (1)

1	Change method from `ident` to `md5` for IPv4 and IPv6 on localhost.

Apply configuration changes for PostgreSQL

sudo systemctl reload postgresql-14

Install PostgreSQL client and server

sudo dnf -y install postgresql-server postgresql

Initialize the PostgreSQL database

sudo postgresql-setup --initdb --unit postgresql

Enable PostgreSQL on system boot and start immediately

sudo systemctl enable --now postgresql

Create an opennms database user and password

sudo -i -u postgres createuser -P opennms

You must provide a password for the opennms database user. This guide uses YOUR-OPENNMS-PASSWORD as a placeholder. Please set a secure password.

Create an empty database and set the owner to the opennms user

sudo -i -u postgres createdb -O opennms opennms

Set a password for PostgreSQL superuser

sudo -i -u postgres psql -c "ALTER USER postgres WITH PASSWORD 'YOUR-POSTGRES-PASSWORD';"

Change YOUR-POSTGRES-PASSWORD to a secure one. The superuser is required to be able to initialize and change the database schema for installation and updates.

Change the access policy for PostgreSQL

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

Allow Horizon to access the database over the local network with an MD5 hashed password

host    all             all             127.0.0.1/32            md5(1)
host    all             all             ::1/128                 md5(1)

1	Change method from `ident` to `md5` for IPv4 and IPv6 on localhost.

Apply configuration changes for PostgreSQL

sudo systemctl reload postgresql

Add PostgreSQL 12 package repository

sudo yum -y install https://download.postgresql.org/pub/repos/yum/reporpms/EL-7-x86_64/pgdg-redhat-repo-latest.noarch.rpm

Install PostgreSQL 12 client and server

sudo yum -y install postgresql12-server postgresql12

Initialize PostgreSQL database

sudo /usr/pgsql-12/bin/postgresql-12-setup initdb

Enable PostgreSQL on system boot and start immediately

sudo systemctl enable --now postgresql-12

Create an opennms database user and password

sudo -i -u postgres createuser -P opennms

You must provide a password for the opennms database user. This guide uses YOUR-OPENNMS-PASSWORD as a placeholder. Please set a secure password.

Create an empty database and set the owner to the opennms user

sudo -i -u postgres createdb -O opennms opennms

Set a password for PostgreSQL superuser

sudo -i -u postgres psql -c "ALTER USER postgres WITH PASSWORD 'YOUR-POSTGRES-PASSWORD';"

Change YOUR-POSTGRES-PASSWORD to a secure one. The superuser is required to initialize and change the database schema for installation and updates.

Change the access policy for PostgreSQL

sudo vi /var/lib/pgsql/12/data/pg_hba.conf

Allow Horizon to access the database over the local network with an MD5 hashed password

host    all             all             127.0.0.1/32            md5(1)
host    all             all             ::1/128                 md5(1)

1	Change method from `ident` to `md5` for IPv4 and IPv6 on localhost.

Apply configuration changes for PostgreSQL

sudo systemctl reload postgresql-12

Install PostgreSQL client and server

sudo apt -y install postgresql

Create an opennms database user and password

sudo -u postgres createuser -P opennms

You must provide a password for the opennms database user. This guide uses YOUR-OPENNMS-PASSWORD as a placeholder. Please set a secure password.

Create an empty database and set the owner to the opennms user

sudo -u postgres createdb -O opennms opennms

Set a password for PostgreSQL superuser

sudo -u postgres psql -c "ALTER USER postgres WITH PASSWORD 'YOUR-POSTGRES-PASSWORD';"

Change YOUR-POSTGRES-PASSWORD to a secure one. The superuser is required to initialize and change the database schema for installation and updates.

Create a project directory for PostgreSQL and create a docker-compose.yml file

mkdir postgres
cd postgres
vi docker-compose.yml

Create the PostgreSQL service and publish the port on your local host

---
version: '3'

volumes:
  data-postgres: {}(1)

services:
  database:(2)
    image: postgres:15(3)
    container_name: database
    environment:(4)
      TZ: 'America/New_York'
      POSTGRES_USER: 'postgres'
      POSTGRES_PASSWORD: 'my-postgres-password'
    volumes:(5)
      - 'data-postgres:/var/lib/postgresql/data'
    healthcheck:(6)
      test: [ "CMD-SHELL", "pg_isready -U postgres" ]
      interval: 10s
      timeout: 3s
      retries: 3
    ports:
      - '5432:5432/tcp'

1	Persist the PostgreSQL database in a local volume.
2	PostgreSQL service is named `database` with a friendly `container_name`.
3	Image reference using the official PostgreSQL image.
4	Set the time zone and the postgres credentials for administrative tasks (for example, creating and changing database schemas for upgrades).
5	Mount the volume for persisting the PostgreSQL database files.
6	Run an internal health check to see if the PostgreSQL instance is ready.

Start the service and run it in background

docker-compose up -d

Verify the PostgreSQL process is up and running

docker-compose ps

The state should be Up (healthy) and the TCP port should be available on all interfaces

  Name                Command                 State               Ports
--------------------------------------------------------------------------------
database   docker-entrypoint.sh postgres   Up (healthy)   0.0.0.0:5432->5432/tcp

Install the core instance

For security reasons, Horizon is designed to run within an organization’s protected intranet. Do not expose the web console and login pages directly to the Internet without appropriate isolation controls (for example, a VPN with multi-factor authentication).

CentOS/RHEL 9
CentOS/RHEL 8
CentOS/RHEL 7
Ubuntu
Debian
Docker

Add repository and import GPG key

sudo dnf -y install https://yum.opennms.org/repofiles/opennms-repo-stable-rhel9.noarch.rpm
sudo rpm --import https://yum.opennms.org/OPENNMS-GPG-KEY

Install Horizon with all built-in dependencies

sudo dnf -y install opennms

If you want time series trending and forecast functions, you must install the R project packages. The additional download size for packages is ~390MB.

(Optional) Install R-core packages for time series trending and forecasting

sudo dnf -y install epel-release
sudo dnf -y install R-core

Disable the OpenNMS Horizon repository after installation to prevent unwanted upgrades when upgrading other packages on the server. After upgrading, Horizon requires manual steps to upgrade configuration files or migrate database schemas to a new version. We recommend that you exclude the Horizon packages from updates except when you plan to perform an upgrade.

Disable auto updates for OpenNMS Horizon

sudo dnf config-manager --disable opennms-repo-stable-*

Verify directory structure with the tree command

sudo dnf -y install tree
tree /opt/opennms -L 1

Directory structure after successful installation

/opt/opennms
├── bin
├── contrib
├── data
├── deploy
├── etc
├── jetty-webapps
├── lib
├── logs -> /var/log/opennms
├── share -> /var/opennms
└── system

Add repository and import GPG key

sudo dnf -y install https://yum.opennms.org/repofiles/opennms-repo-stable-rhel8.noarch.rpm
sudo rpm --import https://yum.opennms.org/OPENNMS-GPG-KEY

Install Horizon with all built-in dependencies

sudo dnf -y install opennms

If you want time series trending and forecast functions you must install the R project packages. The additional download size for packages is ~390 MB.

Install R-core packages for time series trending and forecasting (optional)

sudo dnf -y install epel-release
sudo dnf -y install R-core

Disable the OpenNMS Horizon repository after installation to prevent unwanted upgrades when upgrading other packages on the server. After upgrade, Horizon requires manual steps to upgrade configuration files or migrate database schemas to a new version. We recommend that you exclude the Horizon packages from update except when you plan to perform an upgrade.

Disable auto updates for OpenNMS Horizon

sudo dnf config-manager --disable opennms-repo-stable-*

Verify directory structure with the tree command

sudo dnf -y install tree
tree /opt/opennms -L 1

Directory structure after successful installation

/opt/opennms
├── bin
├── contrib
├── data
├── deploy
├── etc
├── jetty-webapps
├── lib
├── logs -> /var/log/opennms
├── share -> /var/opennms
└── system

Add repository and import GPG key

sudo yum -y install https://yum.opennms.org/repofiles/opennms-repo-stable-rhel7.noarch.rpm
sudo rpm --import https://yum.opennms.org/OPENNMS-GPG-KEY

Install Horizon with all built-in dependencies

sudo yum -y install opennms

If you want time series trending and forecast functions you must install the R project packages. The additional download size for packages is ~390 MB.

Install R-core packages for time series trending and forecasting (optional)

sudo yum -y install epel-release
sudo yum -y install R-core

Disable auto updates for OpenNMS Horizon

sudo yum -y install yum-utils
sudo yum-config-manager --disable opennms-repo-stable-*

Verify directory structure with the tree command

sudo yum -y install tree
tree /opt/opennms -L 1

Directory structure after successful installation

/opt/opennms
├── bin
├── contrib
├── data
├── deploy
├── etc
├── jetty-webapps
├── lib
├── logs -> /var/log/opennms
├── share -> /var/opennms
└── system

Add OpenNMS repository GPG key

curl -fsSL https://debian.opennms.org/OPENNMS-GPG-KEY | sudo gpg --dearmor -o /usr/share/keyrings/opennms.gpg

Add and update apt repository

echo "deb [signed-by=/usr/share/keyrings/opennms.gpg] https://debian.opennms.org stable main" | sudo tee /etc/apt/sources.list.d/opennms.list
sudo apt update

You can safely ignore the message about conflicting distributions (expected stable but got opennms-xx).

Install OpenNMS Horizon with built-in dependencies (optional)

sudo apt -y install opennms

Install R packages for trending and forecasting (optional)

If you want time series trending and forecast functions you have to install the R project packages. The additional download size for packages is ~152 MB.

sudo apt -y install r-recommended

sudo apt-mark hold libopennms-java \
              libopennmsdeps-java \
              opennms-common \
              opennms-db

Verify directory structure with the tree command

sudo apt -y install tree
tree /usr/share/opennms -L 1

Directory structure after successful installation

/usr/share/opennms
├── bin
├── data
├── deploy
├── etc -> /etc/opennms
├── jetty-webapps
├── lib -> ../java/opennms
├── logs -> /var/log/opennms
├── share -> /var/lib/opennms
└── system

Install GnuPG and add OpenNMS repository GPG key

sudo apt -y install curl gnupg ca-certificates
curl -fsSL https://debian.opennms.org/OPENNMS-GPG-KEY | sudo gpg --dearmor -o /usr/share/keyrings/opennms.gpg

Add and update apt repository

echo "deb [signed-by=/usr/share/keyrings/opennms.gpg] https://debian.opennms.org stable main" | sudo tee /etc/apt/sources.list.d/opennms.list
sudo apt update

You can safely ignore the message about conflicting distributions (expected stable but got opennms-xx).

Install OpenNMS Horizon with built-in dependencies

sudo apt -y install opennms

Install R packages for trending and forecasting (optional)

If you want time series trending and forecast functions you must install the R project packages. The additional download size for packages is ~134 MB.

sudo apt -y install r-recommended

sudo apt-mark hold libopennms-java \
              libopennmsdeps-java \
              opennms-common \
              opennms-db

Verify directory structure with the tree command

sudo apt -y install tree
tree /usr/share/opennms -L 1

Directory structure after successful installation

/usr/share/opennms
├── bin
├── data
├── deploy
├── etc -> /etc/opennms
├── jetty-webapps
├── lib -> ../java/opennms
├── logs -> /var/log/opennms
├── share -> /var/lib/opennms
└── system

Create a project directory for Horizon Core and create a docker-compose.yml file.

mkdir horizon
cd horizon
vi docker-compose.yml

---
version: '3'

volumes:(1)
  data-opennms: {}
  data-config: {}

services:
  horizon:(2)
    image: opennms/horizon:31.0.5(3)
    container_name: horizon
    environment:
      TZ: 'America/New_York'(4)
      POSTGRES_HOST: 'my-database-host'(5)
      POSTGRES_PORT: 5432
      POSTGRES_USER: 'postgres'
      POSTGRES_PASSWORD: 'my-postgres-password'
      OPENNMS_DBNAME: 'opennms-core-db'
      OPENNMS_DBUSER: 'opennms'
      OPENNMS_DBPASS: 'my-opennms-db-password'
    volumes:(6)
      - data-opennms:/opennms-data
      - data-config:/opt/opennms/etc
    command: ["-s"]
    ports:(7)
      - '8980:8980/tcp'
      - '8101:8101/tcp'
    healthcheck:
      test: [ 'CMD', 'curl', '-f', '-I', 'http://localhost:8980/opennms/login.jsp' ](8)
      interval: 1m
      timeout: 5s
      retries: 3

1	Volume definitions to persist the Horizon Core data and configuration files.
2	The Horizon Core instance service is named `horizon` with a friendly `container_name`.
3	Image reference using the Horizon container image with the Core services.
4	Set the time zone and the postgres credentials to initialize the database that the Horizon Core instance uses. To list all available time zones, use `timedatectl list-timezones`.
5	Set the host or IP address of the host that runs the PostgreSQL database.
6	Mount directories to store RRD files, PDF reports, and configuration files in a persistent volume.
7	Publish ports to access the web UI and the Karaf shell.
8	Run an internal health check against the web UI to verify service health status.

The process inside the container runs as a non-privileged user with user id 10001. If you want the configuration files in a bind mount on your local host system, make sure you set permissions and ownership accordingly with chown 10001:10001 ./path/to/my/config-dir.

To run a release candidate or a different version, use the public image tags from our repository on DockerHub.

Validate your Docker Compose file

docker-compose config -q

Set up the core instance

CentOS/RHEL 7/8/9
Debian/Ubuntu
Docker

Configure PostgreSQL database access

sudo -u opennms vi /opt/opennms/etc/opennms-datasources.xml

Set credentials to access the PostgreSQL database

<jdbc-data-source name="opennms"
                    database-name="opennms"(1)
                    class-name="org.postgresql.Driver"
                    url="jdbc:postgresql://localhost:5432/opennms"
                    user-name="** YOUR-OPENNMS-USERNAME **"(2)
                    password="** YOUR-OPENNMS-PASSWORD **" />(3)

<jdbc-data-source name="opennms-admin"
                    database-name="template1"
                    class-name="org.postgresql.Driver"
                    url="jdbc:postgresql://localhost:5432/template1"
                    user-name="postgres"(4)
                    password="** YOUR-POSTGRES-PASSWORD **" />(5)

1	Set the database name Horizon should use.
2	Set the user name to access the opennms database table.
3	Set the password to access the opennms database table.
4	Set the postgres user for administrative access to PostgreSQL.
5	Set the password for administrative access to PostgreSQL.

Detect and assign Java environment and persist in /opt/opennms/etc/java.conf

sudo /opt/opennms/bin/runjava -s

Initialize the database and detect system libraries persisted in /opt/opennms/etc/libraries.properties

sudo /opt/opennms/bin/install -dis

Assign CAP_NET_RAW capabilities

Horizon runs as a non-root user, which requires having a Linux kernel greater than 3.10. If you run on an older kernel, and are unable to upgrade your OS, you need to assign CAP_NET_RAW capabilities:

Run systemctl edit --full opennms.service and add the following line to the [Service] section:

AmbientCapabilities=CAP_NET_RAW CAP_NET_BIND_SERVICE

Reload the systemd unit with systemctl daemon-reload and restart the service with systemctl restart opennms.

(For more background on this issue, see H29+ won’t start with permission error to open ICMP socket on Discourse.)

Enable Horizon core instance on system boot and start immediately

sudo systemctl enable --now opennms

Allow connection to the web UI from your network

sudo firewall-cmd --permanent --add-port=8980/tcp
sudo systemctl reload firewalld

Configure PostgreSQL database access

sudo -u opennms vi /usr/share/opennms/etc/opennms-datasources.xml

Set credentials to access the PostgreSQL database

<jdbc-data-source name="opennms"
                    database-name="opennms"(1)
                    class-name="org.postgresql.Driver"
                    url="jdbc:postgresql://localhost:5432/opennms"
                    user-name="** YOUR-OPENNMS-USERNAME **"(2)
                    password="** YOUR-OPENNMS-PASSWORD **" />(3)

<jdbc-data-source name="opennms-admin"
                    database-name="template1"
                    class-name="org.postgresql.Driver"
                    url="jdbc:postgresql://localhost:5432/template1"
                    user-name="postgres"(4)
                    password="** YOUR-POSTGRES-PASSWORD **" />(5)

1	Set the database name Horizon should use.
2	Set the user name to access the opennms database table.
3	Set the password to access the opennms database table.
4	Set the postgres user for administrative access to PostgreSQL.
5	Set the password for administrative access to PostgreSQL.

Detect Java environment and persist in /usr/share/opennms/etc/java.conf

sudo /usr/share/opennms/bin/runjava -s

Initialize the database and detect system libraries persisted in /opt/opennms/etc/libraries.properties

sudo /usr/share/opennms/bin/install -dis

Binding to privileged ports

The core service user must be able to send ICMP echo requests. During setup, the permissions for net.ipv4.ping_group_range are set permanently on boot via /etc/sysctl.d/99-opennms-non-root-icmp.conf. Some system kernels do not honor this setting, and in those cases, additional configuration is required to allow binding to privileged ports. We recommend creating a systemd overlay to add the necessary settings to the service configuration.

Run systemctl edit --full opennms.service and add the following line to the [Service] section:

AmbientCapabilities=CAP_NET_RAW CAP_NET_BIND_SERVICE

Reload the systemd unit with systemctl daemon-reload and restart the service with systemctl restart opennms.

(For more background on this issue, see H29+ won’t start with permission error to open ICMP socket on Discourse.)

Enable Horizon core instance on system boot and start immediately

sudo systemctl enable --now opennms

Allow connection to the web UI from your network

If you are using Uncomplicated Firewall (UFW) as your host firewall, you can allow access to the web user interface with the command:

sudo ufw allow 8980/tcp

Prepare a local configuration directory to run as an unprivileged user

mkdir etc
chown 10001:10001 -R etc

Initialize the database and schema and a configuration directory

docker-compose run horizon -i

Start service in background

docker-compose up -d

You can also use this command when you run upgrades. You must delete the file etc/configured file first. It works as a guard to prevent unnecessary database migration runs on startup.

Show configuration changes from a pristine system with
docker-compose exec -w /opt/opennms/bin horizon ./config-diff.sh -d.

If you changed your configuration files manually you can run the configuration tester with
docker-compose exec horizon bin/config-tester -a

Encrypt database credentials

It is possible to store the PostgreSQL credentials in the secure credentials vault. To achieve this, use the scvcli command line utility to add the credentials, and reference these credentials in opennms-datasources.xml.

Create encrypted credentials for PostgreSQL database connections:

sudo -u opennms ${OPENNMS_HOME}/bin/scvcli set postgres opennms password (1)
sudo -u opennms ${OPENNMS_HOME}/bin/scvcli set postgres-admin postgres password

1	Replace both `password` instances with the actual passwords for your `opennms` and `postgres` database accounts.

Reference encrypted credentials stored in the secure credentials vault:

<jdbc-data-source name="opennms"
                    database-name="opennms"
                    class-name="org.postgresql.Driver"
                    url="jdbc:postgresql://localhost:5432/opennms"
                    user-name="${scv:postgres:username}"
                    password="${scv:postgres:password}" />

<jdbc-data-source name="opennms-admin"
                    database-name="template1"
                    class-name="org.postgresql.Driver"
                    url="jdbc:postgresql://localhost:5432/template1"
                    user-name="${scv:postgres-admin:username}"
                    password="${scv:postgres-admin:password}" />

First-time login and data choices

After you start the Horizon core services, you can access the web application at http://core-instance-ip:8980/opennms. The default user login is admin with the password admin.

After you log in for the first time, immediately change the admin account’s password to a secure one.

The first time you log in, Horizon prompts for permission to allow the Data Choices module to collect and publish anonymous usage statistics to https://stats.opennms.org. The OpenNMS Group uses this anonymized information to help determine product use and to improve the Horizon software. We do not share it with third parties, and we will not use it for sales purposes.

Figure 1. Data sources collection permission prompt

Click Show Me What is Being Sent to see what information we collect. Statistics collection and publication happen only if an admin user opts in.

Admin users can enable or disable statistics collection at any time.

On the top menu bar, click Admin Change Password.
Type your current password and new password in the appropriate fields.
Confirm your new password, and click Submit.

We encourage you to use Horizon with individual user accounts instead of the admin account. If all users have individual accounts, you can see who is completing tasks like clearing or acknowledging alarms.

For information on how to create a personalized user account, see Create a new user in the Quick Start guide.

Receive SNMP traps/informs

Horizon core lets you receive and process SNMP traps and informs out of the box. Horizon services run as an unprivileged user and can’t bind on port numbers below 1024 without escalated privileges. For this reason, the default port for the SNMP trap/inform listener is set to port number 10162/udp instead of the IANA registered port number 162/udp. The following example shows how to configure the local firewall daemon to forward port 162/udp to 10162/udp.

If you need the SNMP trap listener on port 162/udp directly, see the "Binding to privileged ports" steps in Set up the core instance.

CentOS/RHEL 7/8/9
Debian/Ubuntu

Enable Masquerade to allow port forwarding

sudo firewall-cmd --permanent --add-masquerade

Forward SNMP Trap UDP port 162 to 10162

sudo firewall-cmd --permanent --add-port=162/udp
sudo firewall-cmd --permanent --add-port=10162/udp
sudo firewall-cmd --permanent --add-forward-port=port=162:proto=udp:toport=10162
sudo systemctl reload firewalld

Enable Masquerade to allow port forwarding

sudo vi /etc/ufw/before.rules

For SNMP Trap forwarding, add the following lines at the top before the *filter section

*nat
:PREROUTING ACCEPT [0:0]
-A PREROUTING -p udp --dport 162 -j REDIRECT --to-port 10162
COMMIT

Apply the firewall changes

sudo ufw allow in 162/udp
sudo ufw allow in 10162/udp
sudo ufw reload

You can verify your firewall and port forwarding configuration by sending an SNMP trap from a remote system to your Horizon core instance:

snmptrap -v 2c -c public opennms-core-host '' 1.3.6.1.4.1.2021.991.17 .1.3.6.1.2.1.1.6.0 s "Milky Way" (1)(2)

1	By default, Horizon uses the `public` community string. If you changed the community string in Horizon, use that name here.
2	Replace `opennms-core-host` with the IP or FQDN of your Horizon core instance.

On RHEL and CentOS, the snmptrap command line tool is part of the net-snmp-utils. If you run on Debian or Ubuntu, the tool is part of the snmp-utils package.

Your configuration works as expected when you see an SNMP trap event in the web UI.

Log in to the web UI.
Click Status Events All Events.
Verify that you received a uei.opennms.org/generic/traps/EnterpriseDefault event from your test host.

First monitored node

The default configuration will discover a single node with an interface 127.0.0.1 and detect services exposed on the loopback interface, including the OpenNMS-JVM service. Nodes with this service have JMX-based data collection performed on Java JVM statistics such as heap memory and open file handles.

Next steps

See the Quick Start guide for more information on setting up and configuring your Horizon instance.