Installation and configuration

Objectives

  • Install all required OpenNMS Meridian components including PostgreSQL on a single node

  • Run Meridian Core and PostgreSQL with the default configuration (which is not optimized to run in production and monitor large networks)

    • By default your time series storage is RRDtool, which persists RRD files on the local file system

  • Log in to the web UI and change the default admin password

Requirements

  • Credentials to access the Meridian repositories

  • Linux physical server or a virtual machine running a supported Linux operating system

  • Internet access to download the installation packages

  • DNS works and localhost and your server’s host name resolve properly

  • System user with administrative permissions (sudo) to perform installation

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.

Set up PostgreSQL

  • CentOS/RHEL 8

  • CentOS/RHEL 7

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 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/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 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 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

Configure PostgreSQL database access
sudo 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 lines to the [Service] section:

CapabilityBoundingSet=CAP_NET_RAW
AmbientCapabilities=CAP_NET_RAW

Reload the sytemd 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
To receive SNMP Traps or Syslog messages you must allow incoming traffic on your host firewall as well. By default, the OpenNMS Meridian SNMP trap daemon listens on 162/udp and the Syslog daemon listens on 10514/udp. The SNMP Trap daemon is enabled by default, the OpenNMS Syslog daemon is disabled.

First login

After you start the Meridian Core services, access the web application at
http://core-instance-ip:8980/opennms. The default login and password is admin.

Immediately change the password to a secure one.

  1. Open http://core-instance-ip:8980/opennms in your web browser.

  2. Log in with with admin/admin.

  3. Click admin → Change Password in the navigation bar.

  4. Use admin as the current password then type and confirm a new password in the appropriate boxes.

  5. Click Submit.

  6. Log out, then log in with your new password.