PRTG Manual: Failover Cluster Step by Step

This section will guide you through a step-by-step process to set up a failover cluster. Please follow these instructions carefully to successfully integrate two or more PRTG installations into one failover cluster.

icon-i-round-redBefore getting started, please make sure you consider the information in section Failover Cluster Configuration.

icon-prtg-on-demandThis feature is not available in PRTG in the cloud.

Step 1: Install Core Servers

We will start with setting up a single failover cluster, consisting of two PRTG core server installations, each running on an individual server. Please use your license key twice to install the PRTG core server on two different computers.

If you already run an installation of PRTG, this will be your future Master Node. In this case, please install a second core server on another computer only. Make sure you use the same license key for both installations.

Before you start to set up a cluster, please make sure you run exactly the same PRTG version (build number) on all (future) nodes (install updates for existing installations, if necessary).

icon-i-roundOnce the cluster is established, any updates you install on one node will be deployed to all other cluster nodes automatically.

icon-book-arrowsFor details about the installation process, please see Install a PRTG Core Server.

Step 2: Configure Master Node

Decide which of your PRTG core server installations will be your future Master Node. If you already run an installation of PRTG in your network for some time, this should be your master, so your existing monitoring configuration is being kept.

On the Master Node server, from the Windows start menu, open the PRTG Administration Tool. On the Cluster tab, click on the following button:

Create a PRTG Cluster...

  • Click this button to start creating a cluster. The current PRTG core server will then be the Master Node of your cluster.
  • Click Yes to confirm the conversion of this installation into a cluster master node.
Converting an Installation into a Cluster Master Node

Converting an Installation into a Cluster Master Node

  • A new dialog box will appear.
PRTG Administrator: Creating a Cluster Master

PRTG Administrator: Creating a Cluster Master

  • Enter a Cluster Port. This is the port on which the internal communication between the different cluster nodes is sent. Make sure connections between cluster nodes are possible on the selected port.
  • Enter or paste a Cluster Access Key. This is a unique access key. All nodes in a cluster have to be configured with the same cluster access key in order to join the cluster. Connection attempts with the wrong access key will be rejected.
  • We recommend that you use the default value.
  • Save the Cluster Access Key so you have it at hand when configuring your Failover Node(s).
  • After confirming your settings you will be asked to restart Windows services. Please do so in order for your changes to take effect.

Step 3: Configure Failover Node

On the server that will be your Failover Node, open the PRTG Administration Tool. On the Cluster tab, click the following button:

Join a PRTG Cluster...

  • Click this button to add this installation to an existing cluster that already has a Master Node. The current PRTG core server will then be a Failover Node in the cluster.
  • This button is also available if you are currently running your PRTG installation in Cluster Mode: Master Node. This option will then change your master node to a failover node!
  • Click Yes to confirm the conversion of this installation into a failover node.
Converting an Installation into a Cluster Failover Node

Converting an Installation into a Cluster Failover Node

  • A dialog box will appear.
PRTG Server Administrator

PRTG Server Administrator

  • Enter a Master IP address/DNS name for your cluster. It must be reachable from the machine running the failover node.
  • Enter the other settings as defined in the settings of your Master Node. Please make sure you use the same settings on all nodes in your cluster.
  • Enter a Cluster Port. This is the port on which the internal communication between the different cluster nodes is sent. Make sure connections between cluster nodes are possible on the selected port.
  • Enter or paste a Cluster Access Key. This is a unique access key. All nodes in a cluster have to be configured with the same cluster access key in order to join the cluster. Connection attempts with the wrong access key will be rejected.
  • After confirming your settings you will be asked to restart Windows services. Please do so in order for your changes to take effect.

Step 4: Confirm Failover Node

Now you need to confirm the new failover node by setting it to Active in the master node's settings.

In a browser window, log in to the PRTG web interface of the Master Node server.

In the System Administration—Cluster settings, you will see your “Master Node” server in the first line of the cluster list and your “Failover Node” server below.

icon-i-round-redIf you use remote probes outside your local network, for each core server in the cluster use a DNS name or IP address that the probes can reach from the outside. Enter the entries in the Cluster Node Setup table accordingly (see below). The addresses must be valid for both the cluster nodes to reach each other and for remote probes to reach all cluster nodes individually. Remote probes outside your LAN cannot reach private IP addresses or DNS names!

System Administration: Cluster Node Setup

System Administration: Cluster Node Setup

For the “Failover Node”, set the radio button for Node State to Active and Save the changes. The nodes will now connect and exchange configuration data. This may take a few minutes.

Step 5: Check Cluster Connection

In two browser windows, log in to the PRTG web interfaces of both of your PRTG installations. Open the cluster status page in both windows by clicking on the narrow cluster information bars at the top of each window. You should see a cluster status with your two nodes in a Connected state after a few minutes.

PRTG Cluster Status

PRTG Cluster Status

Step 6: Trouble Shooting

Having any problems? If your nodes cannot connect, please see

  • the cluster log entries on the PRTG Status—Cluster Status page of the web interface
  • the core server log file, a text file in the logs directory of your PRTG data folder (see section Data Storage).

In the latest entries of these logs, you can see messages about any errors that might have occurred. These will give you hints on where to find a solution.

If you encounter connection problems between the two cluster nodes, please make sure no software or hardware firewall is blocking communication on the cluster port defined during cluster setup. Communication between the nodes must be possible in both directions in order for the cluster to work properly.

Step 7: Move Sensors to the Cluster Probe Now

That’s it. You have successfully set up your failover cluster. All devices that you create or move under the Cluster Probe are monitored by both servers.

To monitor your existing configuration via all cluster nodes, on your master node, please move your groups, devices, and sensors from the local probe to the cluster probe! Objects, including their settings, will then be transferred to all cluster nodes automatically.

Step 8: Move Custom Content to Failover Nodes

On startup of the cluster master node, maps and custom lookups are automatically transmitted to the failover nodes. While changes to maps are automatically synchronized, you have to manually (re-)load lookups on all nodes. Other custom content has to be copied manually from the according folders on the master node to the same folders on the failover nodes:

Add More Failover Nodes

If you want to add an additional failover node to your cluster, you will need an additional license key for two and three failover nodes, and two additional license keys to run four failover nodes.

icon-i-roundIn a cluster, only core servers running on the same size of license can be combined. For example, you can use several "PRTG 5000" licenses or several "PRTG 1000" licenses in one cluster. To add another failover node to your cluster, please set up a new PRTG core server installation on a new server, using an additional license key. Then proceed with Step 3 and following. Use a second license key to set up both your second and third failover node, and use a third license key to set up your fourth failover node. Each failover cluster is technically limited to five cluster nodes: as a maximum, you can run one master node and four failover nodes in one cluster.

icon-i-round-redStay below 2,500 sensors per cluster for best performance in a single failover. Clusters with more than 5,000 sensors are not supported. For each additional failover node, divide the number of sensors by two.

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