Prerequisites

Before you begin:

• A Clear Linux system updated with sudo swupd update
• Sudo or root access on the Clear Linux system
• Nagios XI installed and reachable
• Network connectivity between Clear Linux and Nagios XI (UDP port 161 open)

Step 1: Install SNMP Tools on Clear Linux

Clear Linux doesn’t include SNMP utilities by default. Install them:

sudo swupd bundle-add net-tools
sudo swupd bundle-add sysadmin-basic

sudo swupd bundle-add net-tools
sudo swupd bundle-add sysadmin-basic

Then install SNMP manually:

sudo swupd bundle-add package-utils
curl -O https://download-ib01.fedoraproject.org/pub/epel/7/x86_64/Packages/n/net-snmp-5.7.2-49.el7.x86_64.rpm
rpm2cpio net-snmp-5.7.2-49.el7.x86_64.rpm | cpio -idmv
sudo cp -r ./usr/* /usr/

sudo swupd bundle-add package-utils
curl -O https://download-ib01.fedoraproject.org/pub/epel/7/x86_64/Packages/n/net-snmp-5.7.2-49.el7.x86_64.rpm
rpm2cpio net-snmp-5.7.2-49.el7.x86_64.rpm | cpio -idmv
sudo cp -r ./usr/* /usr/

Note: Use the latest compatible SNMP RPM or build from source if preferred.

Step 2: Configure SNMP

SNMP v2c Configuration

1. Create a new config file:

sudo mkdir -p /etc/snmp
echo 'rocommunity Str0ngC0mmunity 10.25.5.12' | sudo tee /etc/snmp/snmpd.conf

sudo mkdir -p /etc/snmp
echo 'rocommunity Str0ngC0mmunity 10.25.5.12' | sudo tee /etc/snmp/snmpd.conf

2. Start SNMP (foreground):

sudo /usr/sbin/snmpd -f -Lo

sudo /usr/sbin/snmpd -f -Lo

To run it as a background process, remove -f.

SNMP v3 Configuration (Optional)

SNMP v3 requires a more complex setup. Use net-snmp utilities to create a user:

sudo net-snmp-create-v3-user -ro -a SHA -A Str0ng@uth3ntic@ti0n -x AES -X Str0ngPriv@cy nagios

sudo net-snmp-create-v3-user -ro -a SHA -A Str0ng@uth3ntic@ti0n -x AES -X Str0ngPriv@cy nagios

This may require additional scripting or compiling from source.

Step 3: Open the SNMP Port (UDP 161)

Clear Linux typically uses iptables. Allow SNMP traffic:

sudo iptables -I INPUT -p udp --dport 161 -j ACCEPT
sudo iptables-save > /etc/iptables/rules.v4

sudo iptables -I INPUT -p udp --dport 161 -j ACCEPT
sudo iptables-save > /etc/iptables/rules.v4

Verify:

sudo iptables -L -n | grep 161

sudo iptables -L -n | grep 161

Step 4: Test SNMP Communication

From your Nagios XI server:

SNMP v2c:

snmpwalk -v2c -c Str0ngC0mmunity <clearlinux-ip>

snmpwalk -v2c -c Str0ngC0mmunity <clearlinux-ip>

SNMP v3:

snmpwalk -v3 -u nagios -l authPriv -a SHA -A Str0ng@uth3ntic@ti0n -x AES -X Str0ngPriv@cy <clearlinux-ip>

snmpwalk -v3 -u nagios -l authPriv -a SHA -A Str0ng@uth3ntic@ti0n -x AES -X Str0ngPriv@cy <clearlinux-ip>

Expected Output:

iso.3.6.1.2.1.1.1.0 = STRING: "Linux clearlinux ..."

iso.3.6.1.2.1.1.1.0 = STRING: "Linux clearlinux ..."

Step 5: Add Host in Nagios XI Using SNMP Wizard

1. Log into Nagios XI
2. Navigate to Configure > Run a configuring wizard
3. Select Linux SNMP
4. Enter the Clear Linux IP and SNMP credentials
5. Choose metrics (CPU, memory, disk, etc.)
6. Apply and save configuration

Troubleshooting Tips

• SNMP Daemon Not Running: ps aux | grep snmpd
• Firewall Blocking Traffic: Ensure port 161 is open and rules are persistent
• Permission Issues: Verify snmpd.conf is readable and SNMP is correctly installed

Conclusion

Clear Linux can be monitored via SNMP with a few workarounds despite its stateless design. Once configured, Nagios XI provides deep insight into your system using lightweight, agentless checks.

Resources:

• Nagios SNMP Guide
• Net-SNMP Docs
• Nagios Knowledgebase

This guide details how to install NCPA on Clear Linux and configure it for monitoring within Nagios XI, adapting to Clear Linux’s unique environment.

Prerequisites

Ensure:

• A Clear Linux system (updated with sudo swupd update) with sudo access.
• A running Nagios XI instance (latest version recommended).
• Network connectivity between Clear Linux and Nagios XI (port 5693 open).
• Basic utilities installed: curl, rpm2cpio, cpio, and python3 (Clear Linux includes Python by default).

Step 1: Install Required Tools

Clear Linux doesn’t include rpm2cpio or cpio by default. Install them:

sudo swupd bundle-add dev-utils

Verify:

rpm2cpio --version
cpio --version

Step 2: Download and Extract NCPA

Since Clear Linux doesn’t support RPM packages natively, extract the NCPA RPM manually:

1. Create a Working Directory:

mkdir -p ~/ncpa && cd ~/ncpa

2. Download the Latest-1 NCPA RPM:

curl -O https://assets.nagios.com/downloads/ncpa3/latest-1/ncpa-latest.el9.x86_64.rpm

3. Extract the RPM:

rpm2cpio ncpa-latest.el9.x86_64.rpm | cpio -idmv

Step 3: Deploy NCPA Files

Move the extracted files to their appropriate system locations:

sudo cp -r ./usr/* /usr/
sudo cp -r ./etc/* /etc/
sudo cp -r ./var/* /var/

Step 4: Configure the NCPA Token

1. Edit the Config File:

sudo nano /usr/local/ncpa/etc/ncpa.cfg

2. Set a Secure Token:

community_string = Str0ngT0k3n2025

Step 5: Start the NCPA Listener

Option 1: Manual Start

sudo /usr/local/ncpa/ncpa_listener &

Option 2: Create a Systemd Service

1. Create a service file:

sudo nano /etc/systemd/system/ncpa.service

2. Add:

[Unit]
Description=NCPA Listener Service
After=network.target

[Service]
Type=simple
ExecStart=/usr/local/ncpa/ncpa_listener
Restart=on-failure

[Install]
WantedBy=multi-user.target

3. Enable and start:

sudo systemctl daemon-reload
sudo systemctl enable ncpa
sudo systemctl start ncpa

4. Verify:

sudo systemctl status ncpa

Step 6: Configure the Firewall

1. Add Rule:

sudo iptables -I INPUT -p tcp --dport 5693 -j ACCEPT

2. Persist the Rule:

sudo mkdir -p /etc/iptables sudo iptables-save > /etc/iptables/rules.v4

3. Verify:

sudo iptables -L -n | grep 5693

Step 7: Test NCPA Locally

1. Access the NCPA Web Interface:

https://<ClearLinux-IP>:5693/

2. Accept Certificate

3. Log In:

• Use the token (e.g., Str0ngT0k3n2025) to access the dashboard.

Step 8: Integrate with Nagios XI

1. Log into Nagios XI
2. Run the NCPA Wizard
3. Configure the Host:
   • IP Address: Clear Linux IP
   • Port: 5693
   • Token: Str0ngT0k3n2025
4. Apply Configuration
5. Verify Monitoring

Troubleshooting Tips

• NCPA Not Running:

ps aux | grep ncpa_listener
sudo systemctl status ncpa
cat /usr/local/ncpa/var/log/ncpa.log

• Port Blocked:

sudo nc -zv <ClearLinux-IP> 5693

• Nagios XI Issues:
  • Verify token and IP
  • Check Nagios log: /usr/local/nagiosxi/var/ncpa.log

Conclusion

You’ve manually installed NCPA on Clear Linux and integrated it with Nagios XI. While Clear Linux lacks official NCPA support, this workaround enables robust monitoring. For stability, maintain the systemd service and firewall persistence. Explore passive checks via NRDP or custom plugins.

Resources:

• Nagios NCPA Project
• Nagios Support Forum
• Nagios Knowledgebase