Cluster Management

Cluster Management

Introduction

From version 719, Pandora FMS has a new feature that allows to monitor clusters regardless of the system or the application you use.

The purpose of this system is to ensure fast and easy cluster monitoring, but specially to be user-friendly.

There are two types of clusters:

Active - Passive

These are those clusters where there is only one node running simultaneously.

Active - Active

These are those where the application or service provided is balanced between all cluster nodes.

In a cluster, there are several types of elements:

Common Elements

Modules that must remain active in all cluster nodes, essential for clustering to work.

Balanced Elements

only required for “Active - Passive” type clusters. These are the modules that will be executed as long as the node is active i. e., they will be those modules that will go “balancing” from one node to another of the cluster depending on which machine is running my application at that moment, they will report in one agent or another.

Balanced elements are only needed in the case of clusters of the Active - Pasive type.

Planning monitoring

When monitoring a cluster, this must be taken into account:

If it is an active- active cluster

The common modules to be monitored must be present in all cluster agents. Otherwise it will not be possible to select them.

Then it will be necessary to create identical monitors on all cluster agents to monitor the desired resources.

If it is a passive - active cluster

Common modules will follow the same setup as an active - active. But balance module monitoring must be only configured in the active node.

To be able to monitor “the active node”, use conditioned monitoring, where the module will only report when a series of terms are met.

Configuring a new cluster

To create a new cluster, go to Monitoring > Cluster view.

If this is the first time you access this screen, you should see a page similar to the next one:

Configuring a new cluster Active-Active

Click on “Create” to start the cluster creation wizard, selecting for this example the “Active - Active” cluster option:

Once you have selected a name, a cluster type and a target group, press “next” to access the section on selecting agents.

In this step, select all critical modules for the service to monitor from those agents that have been added to the cluster:

Select a threshold in percentage of nodes (%) to define the cluster states based on common modules (OK/not OK).

After configuring the cluster, add alerts about the different cluster elements so that a certain action is carried out when changing the selected modules to a specific status.

After module evaluation, you will see the cluster map with the status information.

Active - Active cluster view

If your cluster is Active - Active, you can only see the common elements.

This is the view after following the creation example described in the previous section:

There are three different sections:

Cluster Map

(Top left). It represents the agents that make up the cluster and their status.

Status Overview

(Top right). It shows the health status of the cluster, as well as the list of its elements.

Metrics View

(bottom) shows the complete list of metrics registered in the cluster.

If you click on an item in the cluster map, you may see extra information about that item:

Detailed view of cluster status (click on map).

Detailed view of common module status (click on status overview).

When interpreting data shown in data and status columns, it is important to keep in mind the following considerations:

  • The data column shows module percentage in not normal status. For example, if there is a cluster module that contains three modules:
    • If the three of them are in normal status, the value will be 0.
    • If there is two of them in normal and one in warning status, you will see 33.3.
    • If there is one in normal, one in warning and one in critical, you will see 66.7.
  • The status column checks the set thresholds. These thresholds indicate module percentage in not normal status.

Configuring a new Active-Passive cluster

Click on “Create” to start the cluster creation wizard, selecting for this example the “Active - Passive” cluster option:

Once you have selected a name, a cluster type and a target group, press “next” to access the selecting agent section.

This step consists of selecting all the critical modules for the service that you want to monitor from among the agents that have been added to the cluster:

Then a node percentage threshold (%) is selected to define the cluster states based on common modules (OK/not OK).

In this step, the balanced modules are added (those that are reporting in the active agent). The list shows all the modules of all agents that are part of the cluster.

In this last section, the balanced modules critical for the cluster must be selected:

After cluster setup, you may add alerts on the different cluster elements, so that a specific action is performed when changing the desired modules to a specific status.

After evaluating the modules you will see the cluster map with the status information.

Active - passive cluster view

Following the creation example described in the previous section, this is the view:

In there, there is a distinction between three sections:

Cluster Map

(Top left). It represents the agents that make up the cluster and their status.

Status Overview

(Top right). It shows the health status of the cluster, as well as the list of its elements.

Metric View

(Bottom). It shows the complete list of metrics registered in the cluster.

If you click on an item in the cluster map, you may see extra information about that item:

Detailed view of cluster status (click on map).

Detailed cluster module status view (click on status overview).

Go back to Pandora FMS documentation index