Managing Instances In Nagios Log Server can be confusing if we don't know how to view, manage and troubleshoot them.

A clustered application, it consists of one or more instances of Nagios Log Server.

Here at Ibmi Media, as part of our Server Management Services, we regularly help our Customers to perform related Nagios queries.

In this context, we shall look into how to view statistics and manage Nagios Log Server Instances.

Managing Instances In Nagios Log Server

An instance participates in the cluster and acts as a location for the log data to reside. The log data with the use of the Elasticsearch database spreads across the instances.

To manage Nagios Log Server Instances, we navigate to Admin > System > Instance Status.

1. Global Stats

This provides an overall summary of the instances in the cluster. We use this information to get an overview of the performance of the cluster.

2. Instances

We use this table to get a summary of each instance in the cluster. It gives us an overview of how each instance performs.

In the IP column, we click the IP address to bring up more information about that specific instance.

3. Instance Stats

This table will describe the statistics associated with this Nagios Log Server instance.

We use this information to know what the instance is capable of and the hardware they might need to introduce in a new instance.

4. Instance ID

We can find the Instance ID in the top right corner of the page. It is useful while we execute commands or when we review log files.

5. Instance Information

This table contains information about the underlying operating system parameters/capabilities.

i. IP address and Hostname

ii. Load over time

iii. Memory and Swap statistics

iv. CPU Statistics

v. CPU Physical properties

6. Process

Here, we can see the statistics of the current process for this instance.

i. Open File Descriptors

ii. CPU statistics

iii. Memory status

7. File System

The file system used by the instance is found here.

i. File Data Path

ii. Mount and Device Paths

iii. Total and Free Space

iv. Disk Writes, Reads and Size

8. Indices

This table provides information about the indices this instance handles.

For example,

i. Number of Documents and any that have been deleted

ii. Store Size

iii. Totals of Indices, Deletions, Gets, Queries and Fetches

9. Java Virtual Machine (JVM)

This table has statistics about the JVM that runs Elasticsearch.

i. Heap and Non-Heap usage

ii. Uptime, Thread status

iii. GC Times and Counts

iv. Java version and JVM information

10. Thread Pools

A group of idle threads that stand ready until there is work.

i. Formatted by Queue/Peak/Active

ii. Each thread title indicates a section of the pool and the current threads we use

iii. Queued pools are waiting to be run

iv. Peak is the most threads the specific type of thread has ran at once

v. Active is any threads that are currently running

11. System Status

We can control the Elasticsearch and Logstash services on each Nagios Log Server instance via, Admin > System > System Status.

Under Subsystems, we use the Instance drop-down list to change the instance we want to control.

Then we use the Restart/Stop/Start commands to perform that action on the instance.

12. Advanced Management

For more detailed information about instances, we need to execute commands in a terminal session using a curl command.

To do so, we establish a terminal session to one of the Nagios Log Server instances and run:

$ curl -XGET 'http://localhost:9200/_cat/nodes/?v'

This will produce an output similar to the following:

[root@nls-c6x-x86 ~]# curl -XGET ‘http://localhost:9200/_cat/nodes/?v’
host ip heap.percent ram.percent load node.role master name
nls-c6x-x86.box293.local 10.25.5.85 50 70 0.08 d * 76e504ad-a6c9-4798
localhost 127.0.0.1 8 66 0.00 d m d20fa1fa-3a37-4a63
nls-r6x-x64.box293.local 10.25.5.98 24 86 0.00 d m edde1960-0cc2-4892

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