Book Image

Monitoring Elasticsearch

By : Dan Noble, Pulkit Agrawal, Mahmoud Lababidi
Book Image

Monitoring Elasticsearch

By: Dan Noble, Pulkit Agrawal, Mahmoud Lababidi

Overview of this book

ElasticSearch is a distributed search server similar to Apache Solr with a focus on large datasets, a schema-less setup, and high availability. This schema-free architecture allows ElasticSearch to index and search unstructured content, making it perfectly suited for both small projects and large big data warehouses with petabytes of unstructured data. This book is your toolkit to teach you how to keep your cluster in good health, and show you how to diagnose and treat unexpected issues along the way. You will start by getting introduced to ElasticSearch, and look at some common performance issues that pop up when using the system. You will then see how to install and configure ElasticSearch and the ElasticSearch monitoring plugins. Then, you will proceed to install and use the Marvel dashboard to monitor ElasticSearch. You will find out how to troubleshoot some of the common performance and reliability issues that come up when using ElasticSearch. Finally, you will analyze your cluster’s historical performance, and get to know how to get to the bottom of and recover from system failures. This book will guide you through several monitoring tools, and utilizes real-world cases and dilemmas faced when using ElasticSearch, showing you how to solve them simply, quickly, and cleanly.
Table of Contents (15 chapters)
Monitoring Elasticsearch
About the Author
About the Reviewers

Reviewing some case studies

This section discusses some real-world scenarios of Elasticsearch node failure and how to address them.

The ES process quits unexpectedly

A few weeks ago we noticed in Marvel that the Elasticsearch process was down on one of our nodes. We restarted Elasticsearch on this node, and everything seemed to return to normal. However, checking Marvel later on in the week, we notice that the node is down again. We decide to look at the Elasticsearch log files, but don't notice any exceptions. As we don't see anything in the Elasticsearch log, we suspect that the operating system may have killed Elasticsearch. Checking syslog at /var/log/syslog, we see the error:

Out of memory: Kill process 5969 (java) score 446 or sacrifice child

This verifies that the operating system killed Elasticsearch because the system was running out of memory. We check the Elasticsearch configuration and don't see any issues. This node is configured in the same way as the other nodes in the cluster...