Installation and Configuration

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

Objectives

Install all required OpenNMS Meridian components, including PostgreSQL, on a single node.
Run Meridian 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 RRDtool, which persists RRD files on the local file system.
Log in to the web UI and change the admin account’s default password.

Requirements

Credentials to access the Meridian repositories.
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).

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 Meridian server, there must be a policy configured to allow Meridian 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 Meridian 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

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 Meridian 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 Meridian 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 Meridian 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 the core instance

For security reasons, Meridian 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

Add repository and import GPG key

cat << EOF | sudo tee /etc/yum.repos.d/opennms-meridian.repo
[meridian]
name=Meridian for Red Hat Enterprise Linux and CentOS
baseurl=https://REPO_USER:REPO_PASS@meridian.opennms.com/packages/2023/stable/rhel9 (1)
gpgcheck=1
gpgkey=http://yum.opennms.org/OPENNMS-GPG-KEY
EOF

sudo rpm --import https://yum.opennms.org/OPENNMS-GPG-KEY

1	Replace the `REPO_USER` and `REPO_PASS` with your Meridian subscription credentials.

Install Meridian with all built-in dependencies

sudo dnf -y install meridian

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

Disable auto updates for OpenNMS Meridian

sudo dnf config-manager --disable meridian

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

cat << EOF | sudo tee /etc/yum.repos.d/opennms-meridian.repo
[meridian]
name=Meridian for Red Hat Enterprise Linux and CentOS
baseurl=https://REPO_USER:REPO_PASS@meridian.opennms.com/packages/2021/stable/rhel8(1)
gpgcheck=1
gpgkey=http://yum.opennms.org/OPENNMS-GPG-KEY
EOF

sudo rpm --import https://yum.opennms.org/OPENNMS-GPG-KEY

1	Replace the `REPO_USER` and `REPO_PASS` with your Meridian subscription credentials.

Install Meridian with all built-in dependencies

sudo dnf -y install meridian

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

Disable auto updates for OpenNMS Meridian

sudo dnf config-manager --disable meridian

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

cat << EOF | sudo tee /etc/yum.repos.d/opennms-meridian.repo
[meridian]
name=Meridian for Red Hat Enterprise Linux and CentOS
baseurl=https://REPO_USER:REPO_PASS@meridian.opennms.com/packages/2021/stable/rhel7(1)
gpgcheck=1
gpgkey=http://yum.opennms.org/OPENNMS-GPG-KEY
EOF

sudo rpm --import https://yum.opennms.org/OPENNMS-GPG-KEY

1	Replace the `REPO_USER` and `REPO_PASS` with your Meridian subscription credentials.

Install Meridian with all built-in dependencies

sudo yum -y install meridian

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 Meridian

sudo yum -y install yum-utils
sudo yum-config-manager --disable meridian

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

Set up the core instance

CentOS/RHEL 7/8/9

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 Meridian 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

Meridian 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 Meridian 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

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 Meridian 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, Meridian 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 Meridian 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 Meridian 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

Meridian core lets you receive and process SNMP traps and informs out of the box. Meridian 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

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

You can verify your firewall and port forwarding configuration by sending an SNMP trap from a remote system to your Meridian 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, Meridian uses the `public` community string. If you changed the community string in Meridian, use that name here.
2	Replace `opennms-core-host` with the IP or FQDN of your Meridian 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 Meridian instance.