In addition to reading this guide, we recommend you run the Elasticsearch Health Check-Up. It will detect issues and improve your Elasticsearch performance by analyzing your shard sizes, threadpools, memory, snapshots, disk watermarks and more.The Elasticsearch Check-Up is free and requires no installation.
Before you begin reading this guide, we recommend you try running the OpenSearch Error Check-Up which analyzes 2 JSON files to detect many configuration errors.
To evaluate the use of cluster.blocks.read_only and cluster.blocks.read_only_allow_delete in your deployment and resolve any issues related to these concepts, try AutoOps for OpenSearch. It diagnoses problems by analyzing hundreds of metrics collected by a lightweight agent and offers guidance for resolving them.
Overview
A read-only delete block can be applied automatically by the cluster because of a disk space issue, or may be applied manually by an operator to prevent indexing to the OpenSearch cluster.
There are two types of block:
- cluster.blocks.read_only
- cluster.blocks.read_only_allow_delete
A read-only block is typically applied by an operator because some sort of cluster maintenance is taking place or in order to recover cluster stability.
A read-only allow delete block may be applied either automatically or by an operator because of a disk space issue.
How to resolve cluster.blocks.read_only
Check whether the cluster has been blocked via the settings:
GET _cluster/settings
There is probably a good reason why an operator took such an action, so do not remove it without some consideration.
PUT _cluster/settings
{
"transient": {
"cluster.blocks.read_only":null
}
}Index level read-only block
A read-only delete block may be applied to one or more individual indices. You can see where blocks have been applied here:
GET my_index/_settings
To remove the block from one index:
PUT my_index/_settings
{
"index": {
"blocks": {
"read_only": "false"
}
}
}To remove the block from all indices:
PUT _all/_settings
{
"index": {
"blocks": {
"read_only": "false"
}
}
}How to resolve cluster.blocks.read_only_allow_delete
Check whether the cluster has been blocked via the settings:
GET _cluster/settings
There is probably a good reason why an operator took such an action, so do not remove it without some consideration.
PUT _cluster/settings
{
"transient": {
"cluster.blocks.read_only_allow_delete":null
}
}Index level read-only delete block
A read-only delete block may be applied to one or more individual indices. You can see where blocks have been applied here:
GET my_index/_settings
To remove the block from one index:
PUT my_index/_settings
{
"index": {
"blocks": {
"read_only_allow_delete": "false"
}
}
}To remove the block from all indices:
PUT _all/_settings
{
"index": {
"blocks": {
"read_only_allow_delete": "false"
}
}
}
