Best practices

All Script Types are Allowed to Run

Elasticsearch scripts can place heavy loads on clusters if they are not written carefully. It is a best practice to limit the type of..

Bootstrap Checks

Elasticsearch carries out "bootstrap checks" to ensure that important settings have been set correctly. If any of these fail, ES won't start.

Bootstrap Memory Lock is Set to False

Elasticsearch can be configured to automatically prevent memory swapping on its host machine by adding the bootstrap...

Cluster Blocks Read-Only

A read-only delete block can be applied automatically by the cluster because of a disk space issue. It can also be applied manually by...

Dangerous Default Settings

Cluster name and data path are default settings that could be destructive for proper Elasticsearch function if handled incorrectly. If you...

Delete-By-Query

Delete-by-query is an Elasticsearch API, which provides functionality to delete all documents based on the matching query. If you don't...

Enable Adaptive Replica Selection

Adaptive replica selection is a process that prevents a distressed Elasticsearch node from delaying the response to queries. To enable it...

Enable Shard Rebalance and Allocation

Cluster shard rebalancing and allocation are often confused with each other. If cluster shard rebalancing isn't enabled, then...

Expensive Queries are Allowed to Run

By default, Elasticsearch expensive queries are allowed to run. To prevent users from running certain expensive queries, you can add...

File Descriptors

File descriptors are required to keep track of all the files Elasticsearch has open at any given time, as well as all network...

Misuse of Wildcards

It's possible to reduce the risk of accidental deletion of indices by preventing the use of wildcard for destructive operations. To check...

Rest-high-level

Rest-high-level is built on top of low-level rest-client and is a method of communicating with Elasticsearch based on HTTP REST endpoints...

Script Regex is Enabled in Painless Scripts

Script regex is disabled in Elasticsearch by default, so if it has been enabled on your cluster, there may be a reason. Be careful because...

Split Brain

Elasticsearch Split Brain occurs when there is more than 1 master in the cluster. It can be avoided by setting the min number of...

Zen Discovery Settings

Zen discovery settings for cluster formation were deprecated in Elasticsearch V.7 and should be removed from version 7 and above due to...