How to install OpenNMS network monitoring tool in CentOS 8

OpenNMS is a free and open source network monitoring and network management platform for managing corporate networks around the world. It is based on Java and aims to manage thousands of devices from a central location. It has the ability to automatically discover and monitor services or nodes in the network.

feature

• Support SNMP, JMX, WMI, NPRE, NSCLient++ and XMP
• Event-driven architecture
• Support device and application monitoring
• Typological discovery and path break
• Configure and execute service monitor
• Supports layer 2 and layer 3 network topologies

In this tutorial, we will show you how to install and configure OpenNMS on CentOS 8 server.

prerequisites

• Server running CentOS 8.
• The root password is configured for the server.

getting Started

OpenNMS is a Java-based application. Therefore, you will need to install Java in your system. You can install it along with other required packages by running the following command:

dnf install java-11-openjdk-devel curl unzip -y

After installing Java, you can verify the Java version with the following command:

java -version

You should get the following output:

openjdk version "11.0.9" 2020-10-20 LTS
OpenJDK Runtime Environment 18.9 (build 11.0.9+11-LTS)
OpenJDK 64-Bit Server VM 18.9 (build 11.0.9+11-LTS, mixed mode, sharing)

Once completed, you can proceed to the next step.

Install OpenNMS

By default, OpenNMS is not available in the CentOS 8 default repository. Therefore, you need to add the OpenNMS repository to the system.

First, use the following command to add the GPG key:

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

After adding the GPG key, run the following command to add the OpenNMS repository.

dnf install https://yum.opennms.org/repofiles/opennms-repo-stable-rhel8.noarch.rpm

Next, you can install OpenNMS by running the following command:

dnf install opennms -y

This will install OpenNMS, PostgreSQL and other packages in your server.

Configure PostgreSQL

OpenNMS uses PostgreSQL as the database backend. You can initialize the PostgreSQL database with the following command:

postgresql-setup --initdb --unit postgresql

You should get the following output:

 * Initializing database in '/var/lib/pgsql/data'
 * Initialized, logs are in /var/lib/pgsql/initdb_postgresql.log

Next, start the PostgreSQL service and use the following command to enable it to start when the system restarts:

systemctl enable postgresqlsystemctl start postgresql

Next, you will need to create a database and user for PostgreSQL.

First, log in to PostgreSQL using the following command:

su - postgres

After logging in, use the following command to create a user:

[[email protected] ~]$ createuser -P opennms

You will be asked to set a password as shown below:

Enter password for new role: 
Enter it again: 

Next, use the following command to create the database:

[[email protected] ~]$ createdb -O opennms opennms

Next, use the following command to set a password for the PostgreSQL user;

[[email protected] ~]$ psql -c "ALTER USER postgres WITH PASSWORD 'password';"

Next, use the following command to exit from the PostgreSQL Shell:

[[email protected] ~]$ exit;

Next, you will need to modify the PostgreSQL access policy. You can do this by editing the file /var/lib/pgsql/data/pg_hba.conf:

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

Find the following lines:

# IPv4 local connections:
host    all             all             127.0.0.1/32            ident
# IPv6 local connections:
host    all             all             ::1/128                 ident

And, replace them with the following lines: ads

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

Save and close the file, then restart the PostgreSQL service to apply the changes:

systemctl restart postgresql

Next, you will need to define the database in the /opt/opennms/etc/opennms-datasources.xml file.

nano /opt/opennms/etc/opennms-datasources.xml

Change the following lines that match the database:

<jdbc-data-source name="opennms"
                    database-name="opennms"
                    class-name="org.postgresql.Driver"
                    url="jdbc:postgresql://localhost:5432/opennms"
                    user-name="opennms"
                    password="opennms" />

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

Save and close the file when you are done.

Initialize and start OpenNMS

Next, you will need to initialize OpenNMS. First, use the following command to add Java settings:

/opt/opennms/bin/runjava -s

You should get the following output:

runjava: Looking for an appropriate JVM...
runjava: Checking for an appropriate JVM in JAVA_HOME...
runjava: Skipping... JAVA_HOME not set.
runjava: Checking JVM in the PATH: "/etc/alternatives/java"...
runjava: Did not find an appropriate JVM in the PATH: "/etc/alternatives/java"
runjava: Searching for a good JVM...
runjava: Found a good JVM in "/usr/lib/jvm/java-11-openjdk-11.0.9.11-0.el8_2.x86_64/bin/java".
runjava: Value of "/usr/lib/jvm/java-11-openjdk-11.0.9.11-0.el8_2.x86_64/bin/java" stored in configuration file.

Next, initialize the database by running the following command:

/opt/opennms/bin/install -dis

Next, use the following command to enable OpenNMS to start when the system reboots:

systemctl enable --now opennms

You should get the following output:

Synchronizing state of opennms.service with SysV service script with /usr/lib/systemd/systemd-sysv-install.
Executing: /usr/lib/systemd/systemd-sysv-install enable opennms
Created symlink /etc/systemd/system/multi-user.target.wants/opennms.service → /usr/lib/systemd/system/opennms.service.

Now, you can check the status of the OpenNMS service with the following command:

systemctl status opennms

You should get the following output:

? opennms.service - OpenNMS server
   Loaded: loaded (/usr/lib/systemd/system/opennms.service; enabled; vendor preset: disabled)
   Active: active (running) since Wed 2020-11-25 09:21:32 EST; 13s ago
  Process: 26880 ExecStart=/etc/init.d/opennms -s start (code=exited, status=0/SUCCESS)
 Main PID: 27928 (java)
    Tasks: 67 (limit: 12523)
   Memory: 555.6M
   CGroup: /system.slice/opennms.service
           ??27927 bash /etc/init.d/opennms -s start
           ??27928 /usr/lib/jvm/java-11-openjdk-11.0.9.11-0.el8_2.x86_64/bin/java --add-modules=java.base,java.compiler,java.datatransfer,java>

Nov 25 09:21:42 centos8 opennms[26880]: [DEBUG] System property 'opennms.library.jicmp' set to '/usr/lib64/libjicmp.so.  Attempting to load ji>
Nov 25 09:21:42 centos8 opennms[26880]: [INFO] Successfully loaded jicmp library.
Nov 25 09:21:42 centos8 opennms[26880]: [DEBUG] System property 'opennms.library.jicmp' set to '/usr/lib64/libjicmp.so.  Attempting to load ji>
Nov 25 09:21:42 centos8 opennms[26880]: [INFO] Successfully loaded jicmp library.
Nov 25 09:21:42 centos8 opennms[26880]: [DEBUG] System property 'opennms.library.jicmp6' set to '/usr/lib64/libjicmp6.so.  Attempting to load >
Nov 25 09:21:42 centos8 opennms[26880]: [INFO] Successfully loaded jicmp6 library.
Nov 25 09:21:42 centos8 opennms[26880]: [DEBUG] System property 'opennms.library.jicmp' set to '/usr/lib64/libjicmp.so.  Attempting to load ji>
Nov 25 09:21:42 centos8 opennms[26880]: [INFO] Successfully loaded jicmp library.
Nov 25 09:21:42 centos8 opennms[26880]: [DEBUG] System property 'opennms.library.jicmp6' set to '/usr/lib64/libjicmp6.so.  Attempting to load >
Nov 25 09:21:42 centos8 opennms[26880]: [INFO] Successfully loaded jicmp6 library.

At this point, OpenNMS has started and is listening on port 8980. You can check it with the following command:

ss -antpl | grep :8980

You should get the following output:

LISTEN   0        50                          *:8980                   *:*       users:(("java",pid=27928,fd=988)) 

Once completed, you can proceed to the next step.

Configure SELinux and firewall

By default, SELinux is enabled in CentOS 8 server. Therefore, you need to disable it first. You can disable it by editing the /etc/selinux/config file:

nano /etc/selinux/config

Find the following line:

SELINUX=enforcing

And, replace it with the following line:

SELINUX=permissive

Save and close the file, then reboot the system to apply the changes.

Next, use the following command to allow port 8980 through firewalld:

firewall-cmd --permanent --add-port=8980/tcp

Next, reload firewalld to apply the changes:

firewall-cmd --reload

Once completed, you can proceed to the next step.

Access OpenNMS web interface

Now, open your web browser and use the URL to access the OpenNMS web interface https://your server-ip: 8980/opennms. You will be redirected to the OpenNMS login page:

Provide the default administrator username as admin and password as admin, then click log in Button. You should see the following page:

Click on Choose to participate Send anonymous usage statistics to OpenNMS. You should see the OpenNMS dashboard in the following page:

Click on Administrator => change password Change the default password. You should see the following page:

Change your default password and click submit Button. You should see the following page:

Click on + Icon to add a new host.You should see the following page: Ads

Provide a name for the new application and click it is good Button. You should see the following page:

Provide your remote host details and click Stipulate Button. After adding the host, you will see the following page:

Now, click Information => node. You should get the details of the remote host in the following page:

in conclusion

Congratulations! You have successfully installed OpenNMS on the CentOS 8 server. Now you can add unlimited network hosts and devices to OpenNMS and start monitoring from a central location.