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
Yannick Welsch
Lisa Cawley
caminsha
Colin Goodheart-Smithe
Luca Cavanna
Mirek Svoboda
Sam Mingo
James Rodewig
Gordon Brown
David Turner
Jack Conradson
Melori Arellano
Henning Andersen
Alex Doerr
Andrey Ershov
Tim Brooks
Christoph Büscher
Julie Tibshirani
Nhat Nguyen