In addition to reading this guide, run the Elasticsearch Health Check-Up. Detect problems and improve performance by analyzing your shard sizes, threadpools, memory, snapshots, disk watermarks and many more.
Free tool that requires no installation with +1000 users.
Bootstrap Checks in Elasticsearch
Elasticsearch has many settings that can cause significant performance problems if not set correctly. To prevent this happening, Elasticsearch carries out “bootstrap checks” to ensure that these important settings have been covered. If any of the checks fail, Elasticsearch will write an error to the logs and will not start. In this guide we cover common bootstrap checks you should know and how to configure your settings correctly to pass the checks successfully.
Bootstrap checks are carried out when the network.host setting in:
If network host is not set and you use the default localhost, then Elasticsearch will consider the node to be in development mode, and bootstrap checks will not be enforced.
Common issues with bootstrap checks:
If you install elasticsearch using RPM or Debian packages (strongly recommended) then most of the important configuration is already done for you, and the only bootstrap checks you are likely to run up against are the following.
Heap size check:
The minimum and maximum heap sizes specified in jvm.options (or via environment variables) must be equal to one another.
File descriptors check:
Minimum file descriptors must have been set to at least 65535
Memory lock check:
There are various methods used to prevent memory swapping, and you must use one of them. The most common is to set in elasticsearch.yml
For this to be effective you must give permission to elasticsearch to enable this. There are various ways to do so, depending upon your operating system.
Discovery configuration checks:
At least one of the following properties must be configured in elasticsearch.yml to ensure that your node can form a cluster properly:
Less common bootstrap check issues:
If you are not using RPM or debian packages, you may come across the following issues:
Max number of threads check:
You must allow your system to create at least 4096 threads. In linux this is done by editing /etc/security/limits.conf and adjusting the nproc setting.
Max file size check:
Your system should be able to create unlimited file sizes. In linux this is done by editing /etc/security/limits.conf and adjusting the fsize setting
Max virtual memory check:
The system should be able to create unlimited virtual memory for the elasticsearch user.
This is done by editing /etc/security/limits.conf
<user> - as unlimited
Max map count check:
The system must be able to use mmap effectively. This is done by running the command
sysctl vm.max_map_count 262144
The following checks are also carried out, but are rarely found:
OsX File Descriptor Check Client Jvm Check UseS erial GC Check System Call Filter Check Might Fork Check On Error Check On Out Of Memory Error Check Early Access Check G1GC Check All Permission Check
Bootstrap checks are covered in Opster’s Elasticsearch Health Check-Up. The Check-Up analyzes your cluster to detect any errors or issues and provides you with recommendations to resolve them quickly and easily. If you’re having trouble with bootstrap checks, you can run the Check-Up for an accurate analysis of your settings and follow the instructions to ensure your operations continue running smoothly.