The Differences Between Nodes & Elements

Many customers come to us and talk about elements and are confused when we talk about nodes, so let’s dive in and see the difference. 

AĀ nodeĀ is a logical device such as a PC, Server, Switch, Router, IoT Device, Firewall as so forth. A virtualised server or network device would be a node and the physical host it runs on would be another node.

Each node will have items that you want to monitor. CPU, Memory, Disk, Interface, to name a few.Ā  At Opmantek we call theseĀ elements, and big nodes have a small number of elements, but big servers and routers have many elements.

Most network management software companies also refer to these as elements.

It is likely that with each node you monitor, it is sensible to report on that node further than just whether it is up or down. You need to know more about your network infrastructure beyond whether devices are up or down. You will want to measure and instrument for thresholds such as Utilisations, Throughput, Errors, Statuses and so forth. Opmantek CTO Keith Sinclair talks about thatĀ here:

Let us look at how elements are counted:

Say you have a 48 port switch. You want to monitor the device for whether it is online, Interfaces (up/down), CPU, and Memory (RAM).

Element Count:

48 Interface Elements

1 Device up/down Element

1 CPU Element

1 Memory Element

Total = 51 Elements

Let us look at monitoring the same items as a node count:

48 Interface contained in a node

1 Device up/down contained in a node

1 CPU contained in a node

1 Memory contained in a node

Total = 1 Node

Node Graphic - 650

At Opmantek we licenseĀ our productsĀ by node not by element. Based on the examples above, using our 100 node license for your switches would be a 5100 element license with some companies.
Also, consider that the instrumentation that you may decide to set up is also included within that node.Ā  Other companies consider QoS, IPSLA and other types of instrumentation to be additional elements.
So there’s the difference between nodes and elements. It demonstrates how much further a node licence goes when compared to an element licence.
If you would like to see our software in action, request a one to one demonstration with our staff. It is a no-obligation demo with no hard sales push. We just want you to know what we can do, and the quickest way is to show you.

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Getting Started, Configuring the Applications

Introduction

Getting up and running is as simple as finding the virtual machines IP and calling the application page’s URL. After that you will want to enter your license (or get a free license) and we would suggest using the Wizard to kick start your journey.

If you need additional configuration over and above what the wizard offers, our applications are all extremely configurable. The in depth material is hosted on each applications individual space within our wiki. For links to those, see the bottom of this page.

If you need assistance, feel free to ask on Ā Opmantek’s Community Questions siteĀ or contact Opmantek Support.

If you have more in-depth or unique requirements Opmantek is ready and able to customise our solutions to meet your needs – just ask!

Accessing the Application Modules on the VM

Finding the IP and hostname of the VM

Log in to the console using username: omkadmin, password: NM1$88 (you’ll need console access if you don’t know the IP to SSH to).

The default credentials can be foundĀ here.

By default the VM boots with DHCP enabled. On the command line run the below to determine the IP.
ifconfig |Ā grep inet |Ā grep -v inet6 |Ā grep -v "127\.0\.0\.1"
To determine the VMs hostname, run the below.
hostname

Calling a URL

The applications can be access by using the URL http://{ip from above}/omk

You will be presented with the following screen.

All the module names are clickable and link to the respective applications; but you can also navigate directly to NMIS, Open-AudIT or any of the other Opmantek applications.

Simply open your favorite web browser and navigate to:

  • NMIS 9 Virtual Appliance:
    • http://<vm ip address>/nmis9Ā for NMIS,
    • orĀ http://<vm ip address>/omkĀ for the list of all Opmantek applications.

The default access credentials are username ā€œnmisā€, password ā€œnm1888ā€ (more info regarding credentials can be foundĀ on this page).

Once you’ve got either the NMIS dashboard or one of the Opmantek application dashboards open, you can also navigate between modules using the ā€œNMIS Modulesā€ and ā€œModulesā€ menus, respectively.

Getting Started Wizard

On the default /omk page you will see a section in the top left titled ā€œSimple Configuration Wizardā€. We highly recommend you use this to easily configure items such as authentication and email (among others).

Application Module Licensing

The first step to using a module is knowing how to open it, the next is to get a license for it. This process is simple and painless: all products on the appliance now supportĀ free licensesĀ (which are not time-limited but limited to 20 nodes). For these applications the initial dialog offers the generation of such a free license.

Simply click ā€œActivate a Free Licenseā€:

And then fill out the details, note these details are used for your license key and recovery information, ensure they are accurate:

You can also use the ā€œopLicensingā€ module (reachable atĀ http://<vm ip address>/omk/opLicenseĀ or from the Modules menu) to manage your licenses comfortably (including the ability to download previously purchased licenses from the Opmantek website). More info about opLicensingĀ can be found here.

Exploring and Configuring Application Modules

All modules on the Virtual Appliance come with their configuration set to very minimal but safe defaults; to explore the full functionality available you will very likely have to make config modifications to suit your environment. These configuration options are all documented on the Opmantek Community Wiki, in the per-application section (or ā€œApplication Spaceā€); certain common, shared aspects are discussed in theĀ ā€œopCommonā€ space.

For all recent Opmantek applications you’ll find links to the respective sections of Wiki in the ā€œHelpā€ menu (usually under ā€œOnline Documentationā€); there’s also an online version check on the welcome/landing page, and on each application’s ā€œAboutā€ page which helps with keeping your modules up to date.

Our individual applications are covered in great detail in their own wiki spaces (see below).

Getting Started With The Opmantek VM

This page details the four simple steps you need to get started using theĀ Opmantek Virtual Machine.

The virtual machine is a vendor neutral image (OVF) that can be converted and used with VMware (ESXi, Fusion, et al), Virtual Box, KVM and Hyper-V. It’s a quick and easy way to get up and running for Proof of Concepts, Trials and other scenarios where a full production install is not required.Ā Download it, convert it and run it and you’re good to go.

Of course you may have requirements around configuring your Linux machines in a company standard way, and in that case our individual applications are also available to install on a machine built by you to your requirements. To download individual applications,Ā you can here.

Step 1 – Download

Download the Opmantek Virtual Appliance fromĀ here.

Step 2 – Deploy

So you’ve downloaded the latest version of the Opmantek Virtual Appliance and now you want to set it up and take it for a test drive to see how NMIS and the Opmantek networking modules can help you administer your network. No problem. Easy. Simply:

  1. Import the OVA (Open Virtual Appliance Format) or OVF file into VMware, Virtualbox,…
  2. Start up the new VM, optionally set a static IP address.
  3. Access NMIS and the other Opmantek applications in your browser.

For more details on how to do this including specific hypervisor detail, follow the instructions for your hypervisor of choice below:

Step 3 – Configure

Out of the box there is nothing to do – just start the virtual machine and connect to the application URL, done!

If you would like to configure the virtual machine to use HTTPS, set the hostname or set the IP options to your liking, see here – Getting Started, Configuring the Appliance

Step 4 – Run

Start the virtual machine and configure the application settings, see here – Getting Started, Configuring the Applications

Our individual applications are covered in great detail in their own wiki spaces (see below).

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Getting Started, Configuring the Appliance

Out of the box, the Opmantek VM requires no configuration changes to work, however you may wish to make changes so it complements your particular network environment. Items such as using HTTPS, setting the hostname or configuring the IP stack are all configurable.

 

Secure Access with https (optional)

The VM ships with support for secure https access enabled, and you can use https instead of http in any of the URLs mentioned.

However, the included certificate-key pair is the same for all VM downloads, and it is a self-signed certificate (for ā€œopmantek.localā€). This will cause your browser to display security warnings.

If you want to use https access operationally it isĀ highly recommendedĀ that you replace this shared default key-certificate pair with your own (or use an automated certification authority likeĀ letsencrypt/Ā for example).

Debian – Customizing Network Settings (optional)

The Debian team has an excellent wiki page dedicated to customizing the network configuration; this page is available in several languages:

Debian Network Configuration

CentOS – Set a custom IP Address and DNS (optional)

At this point the VM has DHCP enabled, and therefore it will receive a dynamic IP address suitable for your environment. The easiest way to access the VM at that point is from the virtualization software terminal. So go ahead and boot the VM. After the VM is finished booting you will be welcomed by a login prompt. First, log in using theĀ default credentials.

If it’s desirable to customize the network settings we offer the following options:

  • Option #1 – Manual configuration
    The VM appliance is a normal CentOS 7 system, hence all the mechanisms for network configuration in CentOS are available.
    Most specifically you’ll be interested in theĀ  files:
    /etc/hosts/etc/sysconfig/network

    /etc/sysconfig/iptables

    /etc/sysconfig/network-scripts/<interface_name>

  • Option #2 – Use our example network configuration files
    Root’s home directory contains 2 example network configurations, one for static IP’s and one for DHCP. Ā Copy the one you require toĀ /etc/sysconfig/network-scripts/Ā and edit it to suit:
    <codeā€>cp ifcfg-ens192.staticĀ /etc/sysconfig/network-scripts/ <interface_name></codeā€>

Be sure to verify the following settings:

  • IPADDR
  • NETMASK
  • BROADCAST
  • GATEWAY
  • NAME; the interface name as found with the ip address command
  • DEVICE; the interface name as found with the ip address command
  • DNS;

Next restart the network service for the setting to take affect.Ā  In our testing the DHCP address was still present, and the static IP assigned as a secondary (this can be seen with the ā€˜ip address’ command).Ā  The DHCP address can be removed by using the ā€˜ip address command del’ command or be rebooting the system.
TYPE=Ethernet
IPADDR=192.168.10.201
NETMASK=255.255.255.0
BROADCAST=192.168.10.255
GATEWAY=192.168.10.51
PROXY_METHOD=none
BROWSER_ONLY=no
BOOTPROTO=static
DEFROUTE= yes
IPV4_FAILURE_FATAL=no
IPV6INIT= yes
IPV6_AUTOCONF= yes
IPV6_DEFROUTE= yes
IPV6_FAILURE_FATAL=no
IPV6_ADDR_GEN_MODE=stable-privacy
NAME=enp0s3
UUID=9099afe7-6dd6-4aec-bd93-8950b67ab8f5
DEVICE=enp0s3
ONBOOT= yes
DNS1=192.168.10.80
DNS2=8.8.8.8

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Getting Started, Converting the OVF for Other Hypervisors

To use OVF/OVA files with other virtualisation systems like KVM you may have to convert the OVF file to a native format; Two well-known tools for this purpose are virt-v2v (available in CentOS6/RHEL) and virt-convert (in Debian).

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