Index blocks limit the kind of operations that are available on a certain index. The blocks come in different flavours, allowing to block write, read, or metadata operations. The blocks can be set / removed using dynamic index settings, or can be added using a dedicated API, which also ensures for write blocks that, once successfully returning to the user, all shards of the index are properly accounting for the block, for example that all in-flight writes to an index have been completed after adding the write block.
The following dynamic index settings determine the blocks present on an index:
index.blocks.read_only-
Set to
trueto make the index and index metadata read only,falseto allow writes and metadata changes. index.blocks.read_only_allow_delete-
Similar to
index.blocks.write, except that you can delete the index when this block is in place. Do not set or remove this block yourself. The disk-based shard allocator sets and removes this block automatically according to the available disk space.Deleting documents from an index to release resources - rather than deleting the index itself - increases the index size temporarily, and therefore may not be possible when nodes are low on disk space. When
index.blocks.read_only_allow_deleteis set totrue, deleting documents is not permitted. However, deleting the index entirely requires very little extra disk space and frees up the disk space consumed by the index almost immediately so this is still permitted.Important{es} adds the read-only-allow-delete index block automatically when the disk utilization exceeds the flood stage watermark, and removes this block automatically when the disk utilization falls under the high watermark. See Disk-based shard allocation for more information about watermarks, and Fix watermark errors for help with resolving watermark issues. index.blocks.read-
Set to
trueto disable read operations against the index.
index.blocks.write-
Set to
trueto disable data write operations against the index. Unlikeread_only, this setting does not affect metadata. For instance, you can adjust the settings of an index with awriteblock, but you cannot adjust the settings of an index with aread_onlyblock. index.blocks.metadata-
Set to
trueto disable index metadata reads and writes.
Adds an index block to an index.
PUT /my-index-000001/_block/writePUT /<index>/_block/<block>
+
By default, you must explicitly name the indices you are adding blocks to.
To allow the adding of blocks to indices with _all, *, or other wildcard
expressions, change the action.destructive_requires_name setting to false.
You can update this setting in the elasticsearch.yml file
or using the cluster update settings API.
<block>::
(Required, string)
Block type to add to the index.
+
.Valid values for <block>
Details
metadata-
Disable metadata changes, such as closing the index.
read-
Disable read operations.
read_only-
Disable write operations and metadata changes.
write-
Disable write operations. However, metadata changes are still allowed.
+
Defaults to true.
+
Defaults to open.
The following example shows how to add an index block:
PUT /my-index-000001/_block/writeThe API returns following response:
{
"acknowledged" : true,
"shards_acknowledged" : true,
"indices" : [ {
"name" : "my-index-000001",
"blocked" : true
} ]
}