2. Regions

As your network and your NetSpyGlass installation grows, certain steps need to be taken to make sure NetSpyGlass can keep up with this growth. First step is to switch from a single server NetSpyGlass set up to a cluster. This allows you to share the workload across multiple servers to improve scalability. This way, you can take your NetSpyGlass installation to a few thousand devices.

The next step is to introduce regions.

Regions help improve scalability of NetSpyGlass instances monitoring large geographically distributed networks. All devices are divided into groups called regions to which agents are assigned, with several agents per region. In this configuration, servers use configuration file cluster.conf to determine which region each device belongs to and send polling tasks to the agents in each region.

Regions provide a mechanism to control which agent is going to poll each device. Agents should be deployed on servers somewhere close to the devices they poll (in terms of lower network latency). This helps improve the performance and reliability of polling.

Devices are assigned to regions using parameter allocation from configuration file cluster.conf (see below). The value of this parameter is a list of subnet definitions in CIDR notation. Each device is assigned to a region if its address belongs to one of the subnets in the allocation parameter of that region. More on this below.

Although it is possible to assign NSG servers to regions too, this is optional. By default, all servers receive data from all agents. Note that agents must be assigned to regions, even if this is just one default region named ‘world’. Agents are assigned to regions using parameter region in the configuration file agent.conf

2.1. Cluster Configuration

Configuration file cluster.conf is used to allocate devices to regions. This file is located in the directory /opt/netspyglass/home/conf. This configuration file describes regions and defines rules for device allocation to regions.

Here is how file cluster.conf looks like:

REGION_SJC = [ "10.1.1.0/24", "10.23.1.0/24", ]
REGION_IAD = [ "10.101.11.0/24", "10.101.5.0/24", ]

cluster {
    regions = [
        {
            name = sjc
            allocation = ${REGION_SJC}
        }

        {
            name = iad
            allocation = ${REGION_IAD}
        }

        {
            # this region is used for NetSpyGlass own self-monitoring
            name = netspyglass
            # allocation must not be an empty list
            allocation = [ "255.255.255.255/32" ]
        }

    ]
}

Parameters:

• list regions defines cluster regions. Each element in this list is a dictionary with keys name and allocation. The name of the region must match region configured with NetSpyGlass agents (see Configuration parameters)
• allocation - this is a list of subnet addresses in CIDR location. Network devices are allocated to regions according to this list.