A voting-only master-eligible node is a node that can participate in master elections but will not act
as a master in the cluster. In particular, a voting-only node can help elect another master-eligible
node as master, and can serve as a tiebreaker in elections. High availability (HA) clusters require at
least three master-eligible nodes, so that if one of the three nodes is down, then the remaining two
can still elect a master amongst them-selves. This only requires one of the two remaining nodes to
have the capability to act as master, but both need to have voting powers. This means that one of
the three master-eligible nodes can be made as voting-only. If this voting-only node is a dedicated
master, a less powerful machine or a smaller heap-size can be chosen for this node. Alternatively, a
voting-only non-dedicated master node can play the role of the third master-eligible node, which
allows running an HA cluster with only two dedicated master nodes.
Closes#14340
Co-authored-by: David Turner <david.turner@elastic.co>
Adds a metadata field to snapshots which can be used to store arbitrary
key-value information. This may be useful for attaching a description of
why a snapshot was taken, tagging snapshots to make categorization
easier, or identifying the source of automatically-created snapshots.
This commit addresses a few more frequently-asked questions:
* clarifies that bootstrapping doesn't happen even after a full cluster
restart.
* removes the example that uses IP addresses, to try and further encourage the
use of node names for bootstrapping.
* clarifies that auto-bootstrapping might form different clusters on different
hosts, and gives a process for starting again if this wasn't what you wanted.
* adds the "do not stop half-or-more of the master-eligible nodes" slogan that
was notably absent.
* reformats one of the console examples to a narrower width
The `bulk` threadpool is now called `write`, but `bulk` is still
used in some examples. This commit fixes that.
Also, the only way `threadpool.bulk.write: 30` is a valid increase in the size
of this threadpool is if you have 29 processors, which is an odd number of
processors to have. This commit removes the "more threads" bit.
In cases where node names and transport addresses can be muddled, it is unclear
that `cluster.initial_master_nodes: master-a:9300` means to look for a node
called `master-a:9300` rather than a node called `master-a` with transport port
`9300`. This commit adds docs to that effect.
* Clarify that peer recovery settings apply to shard relocation
* Fix awkward wording of 1st sentence
* [DOCS] Remove snapshot recovery reference.
Call out link to [[cat-recovery]].
Separate expert settings.
The example to delete a remote cluster is missing the `skip_unavailable` setting which results in an error:
```
"type": "illegal_argument_exception",
"reason": "missing required setting [cluster.remote.tiny-test.seeds] for setting [cluster.remote.tiny-test.skip_unavailable]"
```
The following phrase causes confusion:
> Alternatively the IP addresses or hostnames (if node name defaults to the
> host name) can be used.
This change clarifies the conditions under which you can use a hostname, and
adds an anchor to the note introduced in (#41137) so we can link directly to it
in conversations with users.
Added documentation for node repurpose tool and included documentation on how to repurpose nodes safely. Adjusted order of tools in `elasticsearch-node` tool since the repurpose tool is most likely to be used.
Co-Authored-By: David Turner <david.turner@elastic.co>
In #33062 we introduced the `cluster.remote.*.proxy` setting for proxied
connections to remote clusters, but left it deliberately undocumented since it
needed followup work so that it could work with SNI. However, since #32517 is
now closed we can add this documentation and remove the comment about its lack
of documentation.
This commit clarifies how the gateway selection works when configuring
remote clusters for CCR or CCS. Specifically, it clarifies compatibility
between different versions which is a very common question.
This commit, mostly authored by @DaveCTurner,
adds documentation for elasticsearch-node tool #37696.
(cherry picked from commit 09425d5a5158c2d3fdad794411b3bbc4bba47b15)
Currently remote compression and ping schedule settings are dynamic.
However, we do not listen for changes. This commit adds listeners for
changes to those two settings. Additionally, when those settings change
we now close existing connections and open new ones with the settings
applied.
Fixes#37201.
`SearchShardIterator` inherits its `compareTo` implementation from `PlainShardIterator`. That is good in most of the cases, as such comparisons are based on the shard id which is unique, even when searching against indices with same names across multiple clusters (thanks to the index uuid being different). In case though the same cluster is registered multiple times with different aliases, the shard id is exactly the same, hence remote results will be returned before local ones with same shard id objects. That is because remote iterators are added before local ones, and we use a stable sorting method in `GroupShardIterators` constructor.
This PR enhances `compareTo` for `SearchShardIterator` to tie break on cluster alias and introduces consistent `equals` and `hashcode` methods. This allows to remove a TODO in `SearchResponseMerger` which otherwise has to handle this special case specifically. Also, while at it I added missing tests around equals/hashcode and compareTo and expanded existing ones.
In #38333 and #38350 we moved away from the `discovery.zen` settings namespace
since these settings have an effect even though Zen Discovery itself is being
phased out. This change aligns the documentation and the names of related
classes and methods with the newly-introduced naming conventions.
Renames the following settings to remove the mention of `zen` in their names:
- `discovery.zen.hosts_provider` -> `discovery.seed_providers`
- `discovery.zen.ping.unicast.concurrent_connects` -> `discovery.seed_resolver.max_concurrent_resolvers`
- `discovery.zen.ping.unicast.hosts.resolve_timeout` -> `discovery.seed_resolver.timeout`
- `discovery.zen.ping.unicast.hosts` -> `discovery.seed_addresses`
Reduces the leader and follower check timeout to 3 * 10 = 30s instead of 3 * 30 = 90s, with 30s still
being a very long time for a node to be completely unresponsive.
With #37000 we made sure that fnial reduction is automatically disabled
whenever a localClusterAlias is provided with a SearchRequest.
While working on #37838, we found a scenario where we do need to set a
localClusterAlias yet we would like to perform a final reduction in the
remote cluster: when searching on a single remote cluster.
Relates to #32125
This commit adds support for a separate finalReduce flag to
SearchRequest and makes use of it in TransportSearchAction in case we
are searching against a single remote cluster.
This also makes sure that num_reduce_phases is correct when searching
against a single remote cluster: it makes little sense to return
`num_reduce_phases` set to `2`, which looks especially weird in case
the search was performed against a single remote shard. We should
perform one reduction phase only in this case and `num_reduce_phases`
should reflect that.
* line length
With #37566 we have introduced the ability to merge multiple search responses into one. That makes it possible to expose a new way of executing cross-cluster search requests, that makes CCS much faster whenever there is network latency between the CCS coordinating node and the remote clusters. The coordinating node can now send a single search request to each remote cluster, which gets reduced by each one of them. from + size results are requested to each cluster, and the reduce phase in each cluster is non final (meaning that buckets are not pruned and pipeline aggs are not executed). The CCS coordinating node performs an additional, final reduction, which produces one search response out of the multiple responses received from the different clusters.
This new execution path will be activated by default for any CCS request unless a scroll is provided or inner hits are requested as part of field collapsing. The search API accepts now a new parameter called ccs_minimize_roundtrips that allows to opt-out of the default behaviour.
Relates to #32125
Abdicates to another master-eligible node once the active master is reconfigured out of the voting
configuration, for example through the use of voting configuration exclusions.
Follow-up to #37712
The "include_type_name" parameter was temporarily introduced in #37285 to facilitate
moving the default parameter setting to "false" in many places in the documentation
code snippets. Most of the places can simply be reverted without causing errors.
In this change I looked for asciidoc files that contained the
"include_type_name=true" addition when creating new indices but didn't look
likey they made use of the "_doc" type for mappings. This is mostly the case
e.g. in the analysis docs where index creating often only contains settings. I
manually corrected the use of types in some places where the docs still used an
explicit type name and not the dummy "_doc" type.
* Default include_type_name to false for get and put mappings.
* Default include_type_name to false for get field mappings.
* Add a constant for the default include_type_name value.
* Default include_type_name to false for get and put index templates.
* Default include_type_name to false for create index.
* Update create index calls in REST documentation to use include_type_name=true.
* Some minor clean-ups around the get index API.
* In REST tests, use include_type_name=true by default for index creation.
* Make sure to use 'expression == false'.
* Clarify the different IndexTemplateMetaData toXContent methods.
* Fix FullClusterRestartIT#testSnapshotRestore.
* Fix the ml_anomalies_default_mappings test.
* Fix GetFieldMappingsResponseTests and GetIndexTemplateResponseTests.
We make sure to specify include_type_name=true during xContent parsing,
so we continue to test the legacy typed responses. XContent generation
for the typeless responses is currently only covered by REST tests,
but we will be adding unit test coverage for these as we implement
each typeless API in the Java HLRC.
This commit also refactors GetMappingsResponse to follow the same appraoch
as the other mappings-related responses, where we read include_type_name
out of the xContent params, instead of creating a second toXContent method.
This gives better consistency in the response parsing code.
* Fix more REST tests.
* Improve some wording in the create index documentation.
* Add a note about types removal in the create index docs.
* Fix SmokeTestMonitoringWithSecurityIT#testHTTPExporterWithSSL.
* Make sure to mention include_type_name in the REST docs for affected APIs.
* Make sure to use 'expression == false' in FullClusterRestartIT.
* Mention include_type_name in the REST templates docs.
Today file-chunks are sent sequentially one by one in peer-recovery. This is a
correct choice since the implementation is straightforward and recovery is
network bound in most of the time. However, if the connection is encrypted, we
might not be able to saturate the network pipe because encrypting/decrypting
are cpu bound rather than network-bound.
With this commit, a source node can send multiple (default to 2) file-chunks
without waiting for the acknowledgments from the target.
Below are the benchmark results for PMC and NYC_taxis.
- PMC (20.2 GB)
| Transport | Baseline | chunks=1 | chunks=2 | chunks=3 | chunks=4 |
| ----------| ---------| -------- | -------- | -------- | -------- |
| Plain | 184s | 137s | 106s | 105s | 106s |
| TLS | 346s | 294s | 176s | 153s | 117s |
| Compress | 1556s | 1407s | 1193s | 1183s | 1211s |
- NYC_Taxis (38.6GB)
| Transport | Baseline | chunks=1 | chunks=2 | chunks=3 | chunks=4 |
| ----------| ---------| ---------| ---------| ---------| -------- |
| Plain | 321s | 249s | 191s | * | * |
| TLS | 618s | 539s | 323s | 290s | 213s |
| Compress | 2622s | 2421s | 2018s | 2029s | n/a |
Relates #33844
This is a follow-up to some discussions around #36399. Currently we have
relatively confusing compression behavior where compression can be
configured for requests based on transport.compress or a specific
setting for a remote cluster. However, we can only compress responses
based on transport.compress as we do not know where a request is
coming from (currently).
This commit modifies the behavior to NEVER compress responses based on
settings. Instead, a response will only be compressed if the request was
compressed. This commit also updates the documentation to more clearly
described transport level compression.
This commit overhauls the documentation of discovery and cluster coordination,
removing mention of the Zen Discovery module and replacing it with docs for the
new cluster coordination mechanism introduced in 7.0.
Relates #32006
This is related to #36652. In 7.0 we plan to deprecate a number of
settings that make reference to the concept of a tcp transport. We
mostly just have a single transport type now (based on tcp). Settings
should only reference tcp if they are referring to socket options. This
commit updates the settings in the docs. And removes string usages of
the old settings. Additionally it adds a missing remote compress setting
to the docs.
Previously persistent task assignment was checked in the
following situations:
- Persistent tasks are changed
- A node joins or leaves the cluster
- The routing table is changed
- Custom metadata in the cluster state is changed
- A new master node is elected
However, there could be situations when a persistent
task that could not be assigned to a node could become
assignable due to some other change, such as memory
usage on the nodes.
This change adds a timed recheck of persistent task
assignment to account for such situations. The timer
is suspended while checks triggered by cluster state
changes are in-flight to avoid adding burden to an
already busy cluster.
Closes#35792
* Lower fielddata circuit breaker default limit
Lower fielddata circuit breaker default limit from 60% to 40% as we have
moved to doc_values for most of the cases.
* merge master in
* update tests
* update docs
This commit changes the format of the `hits.total` in the search response to be an object with
a `value` and a `relation`. The `value` indicates the number of hits that match the query and the
`relation` indicates whether the number is accurate (in which case the relation is equals to `eq`)
or a lower bound of the total (in which case it is equals to `gte`).
This change also adds a parameter called `rest_total_hits_as_int` that can be used in the
search APIs to opt out from this change (retrieve the total hits as a number in the rest response).
Note that currently all search responses are accurate (`track_total_hits: true`) or they don't contain
`hits.total` (`track_total_hits: true`). We'll add a way to get a lower bound of the total hits in a
follow up (to allow numbers to be passed to `track_total_hits`).
Relates #33028
The new limit on the number of open shards in a cluster may be
interpreted by users as a sizing recommendation, but it is not. This
clarifies in the documentation that this is a safety limit, not a
recommendation.
`ScriptDocValues#getValues` was added for backwards compatibility but no
longer needed. Scripts using the syntax `doc['foo'].values` when
`doc['foo']` is a list should be using `doc['foo']` instead.
Closes#22919
This removes the option to run a cluster without enforcing the
cluster-wide shard limit, making strict enforcement the default and only
behavior. The limit can still be adjusted as desired using the cluster
settings API.
This commit adds a rest endpoint for freezing and unfreezing an index.
Among other cleanups mainly fixing an issue accessing package private APIs
from a plugin that got caught by integration tests this change also adds
documentation for frozen indices.
Note: frozen indices are marked as `beta` and available as a basic feature.
Relates to #34352
This changes the current script.max_size_in_bytes to be dynamic so it can be
set through the cluster settings API. This setting is also applied to inline scripts
in the compile method of ScriptService to prevent excessively long inline
scripts from being compiled. The script length limit is removed from Painless as
this is no longer necessary with the protection in compile.
When we connect to remote clusters, there may be a few more routers/firewalls in-between compared to when we connect to nodes in the same cluster. We've experienced cases where firewalls drop connections completely and keep-alives seem not to be enough, or they are not properly configured. With this commit we allow to enable application-level pings specifically from CCS nodes to the selected remote nodes through the new setting `cluster.remote.${clusterAlias}.transport.ping_schedule`. The new setting is similar `transport.ping_schedule` but it does not affect intra-cluster communication, pings are only sent to specific remote cluster when specifically enabled, as they are disabled by default.
Relates to #34405
This change adds a section about the global search setting
`indices.query.bool.max_clause_count` that limits the number of boolean clauses
allowed in a Lucene BooleanQuery.
Closes#19858
In a future major version, we will be introducing a soft limit on the
number of shards in a cluster based on the number of nodes in the
cluster. This limit will be configurable, and checked on operations
which create or open shards and issue a warning if the operation would
take the cluster over the limit.
There is an option to enable strict enforcement of the limit, which
turns the warnings into errors. In a future release, the option will be
removed and strict enforcement will be the default (and only) behavior.
With remote clusters taking on a larger role, we have make the
infrastructure more generic than being tied to cross-cluster search
(CCS). We want to refer to the remote clusters configuration in the
cross-cluster replication (CCR) docs. Yet, these docs are still tied to
CCS. This commit extracts the remote clusters docs from CCS (with some
wording changes to make them more general) so that we can refer to them
in the CCR docs.
As user-defined cluster metadata is accessible to anyone with access to
get the cluster settings, stored in the logs, and likely to be tracked
by monitoring solutions, it is useful to clarify in the documentation
that it should not be used to store secret information.
It is not obvious that a filesystem-level backup may capture an inconsistent
set of files that may fail on restore, or (worse) succeed having silently
discarded some data. This change spells the out, and reorganises the first page
or so of the snapshot/restore docs to make this warning fit more nicely.
This change adds a `_source` only snapshot repository that allows to wrap
any existing repository as a _backend_ to snapshot only the `_source` part
including live docs markers. Snapshots taken with the `source` repository
won't include any indices, doc-values or points. The snapshot will be reduced in size and
functionality such that it requires full re-indexing after it's successfully restored.
The restore process will copy the `_source` data locally starts a special shard and engine
to allow `match_all` scrolls and searches. Any other query, or get call will fail with and unsupported operation exception. The restored index is also marked as read-only.
This feature aims mainly for disaster recovery use-cases where snapshot size is
a concern or where time to restore is less of an issue.
**NOTE**: The snapshot produced by this repository is still a valid lucene index. This change doesn't allow for any longer retention policies which is out of scope for this change.
With features like CCR building on the CCS infrastructure, the settings
prefix search.remote makes less sense as the namespace for these remote
cluster settings than does a more general namespace like
cluster.remote. This commit replaces these settings with cluster.remote
with a fallback to the deprecated settings search.remote.
Adds a place for users to store cluster-wide data they wish to associate
with the cluster via the Cluster Settings API. This is strictly for
user-defined data, Elasticsearch makes no other other use of these
settings.
Today we support a static list of seed hosts in core Elasticsearch, and allow a
dynamic list of seed hosts to be provided via a file using the `discovery-file`
plugin. In fact the ability to provide a dynamic list of seed hosts is
increasingly useful, so this change moves this functionality to core
Elasticsearch to avoid the need for a plugin.
Furthermore, in order to start up nodes in integration tests we currently
assign a known port to each node before startup, which unfortunately sometimes
fails if another process grabs the selected port in the meantime. By moving the
`discovery-file` functionality into the core product we can use it to avoid
this race.
This change also moves the expected path to the file from
`$ES_PATH_CONF/discovery-file/unicast_hosts.txt` to
`$ES_PATH_CONF/unicast_hosts.txt`. An example of this file is not included in
distributions.
For BWC purposes the plugin still exists, but does nothing more than create the
example file in the old location, and issue a warning when it is used. We also
continue to support the old location for the file, but warn about its
deprecation.
Relates #29244Closes#33030
We do not support intra-cluster connections on multiple interfaces, but the
documentation indicates that we will in future. In fact there is currently no
plan to support this, so the forward-looking documentation is misleading. This
commit
- removes the misleading sentence
- fixes that a transport profile affects outbound connections, not inbound ones
- tidies up some nearby text
With this commit we introduce a new circuit-breaking strategy to the parent
circuit breaker. Contrary to the current implementation which only accounts for
memory reserved via child circuit breakers, the new strategy measures real heap
memory usage at the time of reservation. This allows us to be much more
aggressive with the circuit breaker limit so we bump it to 95% by default. The
new strategy is turned on by default and can be controlled with the new cluster
setting `indices.breaker.total.userealmemory`.
Note that we turn it off for all integration tests with an internal test cluster
because it leads to spurious test failures which are of no value (we cannot
fully control heap memory usage in tests). All REST tests, however, will make
use of the real memory circuit breaker.
Relates #31767
So far the in-flight request circuit breaker has only accounted for the
on-the-wire representation of a request. However, we convert the raw
request into XContent internally which increases the overhead.
Therefore, we increase the value of the corresponding setting
`network.breaker.inflight_requests.overhead` from one to two. While this
value is still rather conservative (we assume that the representation as
structured objects has no overhead compared to the byte[]), it is closer
to reality than the current value.
Relates #31613
The documentation for the account circuit breaker listed the settings for it's limit and overhead to be `network.breaker.accounting.limit` and `network.breaker.accounting.overhead` when in `HieratchyCircuitBreakerService` it seems the settings are actually `indices.breaker.accounting.limit` and `indices.breaker.accounting.overhead`.
Include size of snapshot in snapshot metadata
Adds difference of number of files (and file sizes) between prev and current snapshot. Total number/size reflects total number/size of files in snapshot.
Closes#18543
This commit reintroduces 31251c9 and 63a5799. These commits introduced a
memory leak and were reverted. This commit brings those commits back
and fixes the memory leak by removing unnecessary retain method calls.
This reverts commit 31251c9 introduced in #30695.
We suspect this commit is causing the OOME's reported in #30811 and we will use this PR to test this assertion.
This is related to #29500 and #28898. This commit removes the abilitiy
to disable http pipelining. After this commit, any elasticsearch node
will support pipelined requests from a client. Additionally, it extracts
some of the http pipelining work to the server module. This extracted
work is used to implement pipelining for the nio plugin.
This commit removes the http.enabled setting. While all real nodes (started with bin/elasticsearch) will always have an http binding, there are many tests that rely on the quickness of not actually needing to bind to 2 ports. For this case, the MockHttpTransport.TestPlugin provides a dummy http transport implementation which is used by default in ESIntegTestCase.
closes#12792
A NullPointerException is thrown when trying to create or delete
a snapshot in a repository that has been written to by an older
Elasticsearch after writing to it with a newer Elasticsearch version.
This is because the way snapshots are formatted in the repository
snapshots index file changed in #24477.
This commit changes the parsing of the repository index file so that
it now detects a corrupted index file and fails early the snapshot
operation.
closes#29052
This commit renames the bulk thread pool to the write thread pool. This
is to better reflect the fact that the underlying thread pool is used to
execute any document write request (single-document index/delete/update
requests, and bulk requests).
With this change, we add support for fallback settings
thread_pool.bulk.* which will be supported until 7.0.0.
We also add a system property so that the display name of the thread
pool remains as "bulk" if needed to avoid breaking users.
Now that single-document indexing requests are executed on the bulk
thread pool the index thread pool is no longer needed. This commit
removes this thread pool from Elasticsearch.
We want to remove the index thread pool as it is no longer needed since
single-document indexing requests are executed as bulk requests
now. Analyze requests are also executed on the index thread pool though
and they need a thread pool to execute on. The bulk thread does not seem
like the right thread pool, let us keep that thread pool conceptually
for bulk requests and free for bulk requests. None of the existing
thread pools make sense for analyze requests either. The generic thread
pool would be a terrible choice since it has an unbounded queue and that
is a bad idea for user-facing APIs. This commit introduces a small by
default (size=1, queue_size=16) thread pool for analyze requests.
Control max size and count of warning headers
Add a static persistent cluster level setting
"http.max_warning_header_count" to control the maximum number of
warning headers in client HTTP responses.
Defaults to unbounded.
Add a static persistent cluster level setting
"http.max_warning_header_size" to control the maximum total size of
warning headers in client HTTP responses.
Defaults to unbounded.
With every warning header that exceeds these limits,
a message will be logged in the main ES log,
and any more warning headers for this response will be
ignored.
I am not sure why we have this leniency for HTTP max content length, it
has been there since the beginning
(5ac51ee93f) with no explanation of its
source. That said, our philosophy today is different than the philosophy
of the past where Elasticsearch would be quite lenient in its handling
of settings and today we aim for predictability for both users and
us. This commit removes leniency in the parsing of
http.max_content_length.
This commit adds a new setting `cluster.persistent_tasks.allocation.enable`
that can be used to enable or disable the allocation of persistent tasks.
The setting accepts the values `all` (default) or `none`. When set to
none, the persistent tasks that are created (or that must be reassigned)
won't be assigned to a node but will reside in the cluster state with
a no "executor node" and a reason describing why it is not assigned:
```
"assignment" : {
"executor_node" : null,
"explanation" : "persistent task [foo/bar] cannot be assigned [no
persistent task assignments are allowed due to cluster settings]"
}
```
Update allocation awareness docs
Today, the docs imply that if multiple attributes are specified the the
whole combination of values is considered as a single entity when
performing allocation. In fact, each attribute is considered separately. This
change fixes this discrepancy.
It also replaces the use of the term "awareness zone" with "zone or domain", and
reformats some paragraphs to the right width.
Fixes#29105
Values for the network.host setting can often contain a colon which is a
character that is considered special by YAML (these arise in IPv6
addresses and some of the special tags like ":ipv4"). As such, these
values need to be quoted or a YAML parser will be unhappy with
them. This commit adds a note to the docs regarding this.
Cluster settings shouldn't leak into the next test.
I played with failing the test if it left over any settings but that
felt like it added more ceremony then it was worth. The advantage is
that any test that intentionally wants to leave settings in place after
the test would fail and require looking at but, so far as I can tell, we
don't have any such tests.
Clear the disk watermark after the snippet showing users how to set it.
Without this our tests will fail if the disks have less than 10GB free.
Closes#28325
Allowing `_doc` as a type will enable users to make the transition to 7.0
smoother since the index APIs will be `PUT index/_doc/id` and `POST index/_doc`.
This also moves most of the documentation to `_doc` as a type name.
Closes#27750Closes#27751
* Add accounting circuit breaker and track segment memory usage
This commit adds a new circuit breaker "accounting" that is used for tracking
the memory usage of non-request-tied memory users. It also adds tracking for the
amount of Lucene segment memory used by a shard as a user of the new circuit
breaker.
The Lucene segment memory is updated when the shard refreshes, and removed when
the shard relocates away from a node or is deleted. It should also be noted that
all tracking for segment memory uses `addWithoutBreaking` so as not to fail the
shard if a limit is reached.
The `accounting` breaker has a default limit of 100% and will contribute to the
parent breaker limit.
Resolves#27044
Today Cross Cluster Search requires at least one node in each remote cluster to be up once the cross cluster search is run. Otherwise the whole search request fails despite some of the data (either local and/or remote) is available. This happens when performing the _search/shards calls to find out which remote shards the query has to be executed on. This scenario is different from shard failures that may happen later on when the query is actually executed, in case e.g. remote shards are missing, which is not going to fail the whole request but rather yield partial results, and the _shards section in the response will indicate that.
This commit introduces a boolean setting per cluster called search.remote.$cluster_alias.skip_if_disconnected, set to false by default, which allows to skip certain clusters if they are down when trying to reach them through a cross cluster search requests. By default all clusters are mandatory.
Scroll requests support such setting too when they are first initiated (first search request with scroll parameter), but subsequent scroll rounds (_search/scroll endpoint) will fail if some of the remote clusters went down meanwhile.
The search API response contains now a new _clusters section, similar to the _shards section, that gets returned whenever one or more clusters were disconnected and got skipped:
"_clusters" : {
"total" : 3,
"successful" : 2,
"skipped" : 1
}
Such section won't be part of the response if no clusters have been skipped.
The per cluster skip_unavailable setting value has also been added to the output of the remote/info API.
Removing several occurrences of this typo in the docs and javadocs, seems to be
a common mistake. Corrections turn up once in a while in PRs, better to correct
some of this in one sweep.
The current script service has a script compilation limit for a one
minute window. This is set to a small default value of 15. Instead of
increasing that default value, this commit introduces a new setting
that allows to configure a rate per time unit, so that the script service can deal with bursts better.
The new setting is named `script.max_compilations_rate`,
requires a nonnegative number and a positive time value.
The default is `75/5m`, which is equivalent to the existing 15 per minute.
The names of two settings in the script security docs are incorrect,
referring to the prefix as "scripts" instead of "script". This commit
fixes this issue.
Relates #26236
This commit adds a small note to the discovery docs to include a note
that we recommend that the unicast hosts list be maintained as the list
of master-eligible nodes in the cluster.
Relates #25991
Requests that execute a stored script will no longer be allowed to specify the lang of the script. This information is stored in the cluster state making only an id necessary to execute against. Putting a stored script will still require a lang.