Table of Contents

Pollers: General Overview, Deployment Strategy, Build Out & Setup

Saied Ahadi Updated by Saied Ahadi

Read Time: 4 mins

What is a Poller?

A Poller is a device that typically sits within your network in order to monitor and collect network information on deployed devices and bring that data back into Sonar. Additionally, a poller will be able to determine which deployed devices on accounts are connected to which equipment on network sites.

One poller can monitor about one to two thousand devices, if enough resources are given. However, a poller can possibly perform worse depending on your network build out and what kind of equipment you have deployed. The requirements for a poller are 4 GB of RAM and a dual core CPU with Ubuntu 20.04; While having a more powerful machine helps with polling, it is recommended to have 2 or 3 pollers if your network consists of 3000 devices or more.

Deployment Strategy

The poller should be hosted within your network rather than outside (Digital Ocean, AWS or Azure). While you can host your poller on the cloud, it is recommended to be as close to your deployed devices as possible. There are 2 reasons why this is recommended: first, being that you will get a quicker response from the devices you are polling, and second, it is more secure than hosting it on the cloud.

Additionally, if you have a larger network that spans a large area, it is recommended to put the pollers as close as possible to the devices you are polling - this ensures that you have accurate information.

Build Out

To create a poller in Sonar, go to: Settings menu > Monitoring > Pollers. Then, click on the "Create Poller" button to create a new poller. In the window that appears, name the poller to something recognizable (a good rule of thumb is to name the poller on where it is located or what subnets it is polling) and choose the subnets you want to monitor. This is also where you can also set the priority of that subnet.

Since each subnet can have a priority set (1 being the highest and 10 being the lowest) - when a device is being monitored and it has multiple IPs assigned, and a poller is set to monitor more than one of the subnets that the IPs are within, the poller will use the subnet with the lowest priority # when deciding which IP to use for SNMP and ICMP queries. Therefore, the lower the priority = the more accurate information you are getting for that subnet.

By checking off additional boxes, you can add more subnets to be polled by that poller.

To quickly select or deselect all subnets, use the All / None buttons.

When creating additional pollers, the Create Poller window will indicate any subnets that are currently being polled by one of your other pollers:

Once a poller has been created, you will be taken back to the poller screen with all your pollers - this is also where you can view the associated API key.

From here, we can install the poller on a virtual machine. The virtual machine should have 4 GB of RAM, at least 2 cores, and 20 GB of hard drive space.

Additionally, we need to set how often we will poll information on accounts and tower equipment. This information is set in Poller Settings screen, which can be accessed by navigating to the Settings menu > Monitoring > Poller Settings.

  • Account Polling: Determines how often deployed equipment on accounts are polled. This should not be set to anything lower than 5 minutes unless you have a very small network.
  • Infrastructure polling: Determines how often deployed equipment on tower sites are polled. Generally we want to poll this info every 2 to 5 minutes.

Instructions on how to install the Poller on a Virtual Machine can be found on our GitHub here.

Poller Troubleshooting

Poller has not returned any data to Sonar in the past 5 minutes:
  • Check the API key and the link to the Sonar instance to make sure both are correct.
  • Poller is polling too many devices or too frequently. Uncheck some of the subnets to see if it makes a difference, and if so, deploy additional pollers. Additionally, you might have to increase your polling settings for accounts.
  • Poller is running out of space. Check if debug mode is On by running nano /opt/poller/.env and if so turn it off. Check the hard drive space by running df -h .
Device in Sonar shown in a down state:
  • Check to see if both ICMP and SNMP are down. If just SNMP then the device is not down and it is showing a false positive.
  • Run SNMP walk on poller to make sure the device is able to respond to SNMP requests. If it does not, make sure SNMP is enabled on the device and the community string matches what is defined on the template. Additionally, make sure you have not overwritten the SNMP version or the community string on the device.
  • If only certain devices are down (especially Ubiquiti) increase the SNMP_timeout to 1.5 to 2 seconds and increase the SNMP retries to 1.

How did we do?

Building a Monitoring Template

Building Alerting Rotations