This commit adds the Desired Nodes API, allowing orchestrators
that manage Elasticsearch clusters to let the system know about the
current/planned topology that the cluster will run on.
This allows the system to take better decisions based on the entire
cluster topology, including nodes that will be added/removed in the
near future.
The `GET _cluster/state` API is really only suitable for debugging or
diagnostics. Its response format is not documented since it changes
fairly freely between versions.
Today we mention in its docs that this API is unstable, and deliberately
omit a description of its response format, but we don't explicitly say
that it's only for diagnostics and is unsuitable for consumption by
external tools that might try and use it for monitoring.
This commit adjusts the docs to give some more explicit guidance about
how it should and shouldn't be used.
`GET _nodes/stats` returns statistics about indexing pressure for each node.
With this commit `GET _cluster/stats` now returns stats about indexing pressure
computed by aggregating the indexing pressure stats of each node in the
cluster.
Closes#79788
Adds to the transport node stats a record of the distribution of the
times for which a transport thread was handling a message, represented
as a histogram.
Closes#80428
* Revert "Return 200 OK response code for a cluster health timeout (#78968)"
This reverts commit a2c3daea
* Revert "Allow deprecation warning for the return_200_for_cluster_health_timeout parameter (#80178)"
This reverts commit 1c711e35fc.
* Revert "Drop pre-7.2.0 wire format in ClusterHealthRequest (#79551)"
This reverts commit b9fbe66ab0.
* Revert "Adjust the BWC version for the return200ForClusterHealthTimeout field (#79436)"
This reverts commit f60bda5685.
* Revert "Use query param instead of a system property for opting in for new cluster health response code (#79351)"
This reverts commit 8901a999
* Revert "Deprecate returning 408 for a server timeout on `_cluster/health` (#78180)"
This reverts commit f266eb32
* Drop pre-7.2.0 wire format in ClusterHealthRequest (#79551)
This reverts commit fa4d562c
* Revert "Disable BWC for #80821 (#80839)"
This reverts commit cb0e73e2fc.
Co-authored-by: Elastic Machine <elasticmachine@users.noreply.github.com>
#80556 reverted the deprecation of transient cluster settings. This replaces deprecation language in the docs with a warning/recommendation to avoid transient settings.
Closes#80557
# Conflicts:
# docs/reference/migration/migrate_7_16.asciidoc
Changes:
* Adds a transient settings migration guide to the 7.16 docs.
* Updates the related deprecation docs to link to the guide.
Closes#80055
Relates to #79167.
The original change was implemented in #78940, bu we have decided to move from a system property to an a request parameter, so Cloud users/clients have an easier way to opt-in for the new status code.
Relates #70849
Since #65905 Elasticsearch has determined the Java heap settings
from node roles and total system memory.
This change allows the total system memory used in that calculation
to be overridden with a user-specified value. This is intended to
be used when Elasticsearch is running on a machine where some other
software that consumes a non-negligible amount of memory is running.
For example, a user could tell Elasticsearch to assume it was
running on a machine with 3GB of RAM when actually it was running
on a machine with 4GB of RAM.
The system property is `es.total_memory_bytes`, so, for example,
could be specified using `-Des.total_memory_bytes=3221225472`.
(It is specified in bytes rather than using a unit, because it
needs to be parsed by startup code that does not have access to
the utility classes that interpret byte size units.)
This PR changes uses of transient cluster settings to
persistent cluster settings.
The PR also deprecates the transient settings usage.
Relates to #49540
The docs for `GET _nodes/<node>/<metric>` omitted a couple of metrics
and indicated that this API returned dynamic stats rather than static
info. They also didn't mention that `_all` is a legal value, nor
did it give a way to suppress all metrics even though this is possible.
This commit adjusts the docs and adds tests to ensure that selecting
metrics works as expected and to ensure that there is a future-proof
legal way to suppress all metrics.
Closes#79187
Co-authored-by: James Rodewig <40268737+jrodewig@users.noreply.github.com>
If the _nodes/stats API received a level=shards request parameter, then the response would have two "shards" fields,
which would cause problems with json parsers. This commit renames the "shards" field that currently only contains
"total_count" to "shard_stats".
Relates #78311#75433
This commit introduces into the node stats API various statistics to
track the time that the elected master spends in various phases of the
cluster state publication process.
Relates #76625
To return the JVM `uptime` metric, the `human` query parameter must be `true`.
Co-authored-by: Adam Locke <adam.locke@elastic.co>
Co-authored-by: James Rodewig <40268737+jrodewig@users.noreply.github.com>
Today we often encounter users that are confused by the behaviour of
calling `GET _cluster/allocation/explain` without a body: it _seems_ to
work, but it explains a random shard, and if this isn't the shard
they're thinking of then it's unclear how to proceed.
With this commit we add a note to the response when a shard was randomly
chosen indicating that it is possible, and possibly useful, to explain a
different shard. We also adjust the exception message in the case when
all shards are assigned to indicate why it's an invalid request and what
to do to make it valid.
* Adding shard count to _nodes/stats api
Added a shards section to each node returned by the _nodes/stats api. Currently this new section only contains a total count of all shards on the node.
This commit adds a `cancelled` flag to each cancellable task in the
response to the list tasks API, allowing users to see that a task has
been properly cancelled and will complete as soon as possible.
Closes#72907
Changes:
* Renames 'full copy searchable snapshot' to 'fully mounted index.'
* Renames 'shared cache searchable snapshot' to 'partially mounted index.'
* Removes some unneeded cache setup instructions for the frozen tier. We added a default cache size with #71844.
Today the only example of calling the cluster allocation explain API above the
fold is the bare `GET /_cluster/allocation/explain` which kind of works but is
not usually what the user wants. This commit changes the docs so that we open
with an example showing how we usually expect it to be called. This will make
it clearer that you should normally specify exactly for which shard you want an
explanation. It also tidies up a few other wrinkles in these docs.
Co-authored-by: James Rodewig <40268737+jrodewig@users.noreply.github.com>
We have recently introduced the ability to associate an indexed field with a script. This commit updates the existing mappings stats to output stats about the script, similar to what we already do for runtime fields.
With shared cache searchable snapshots we have shards that have a size
in S3 that differs from the locally occupied disk space. This commit
introduces `store.total_data_set_size` to node and indices stats, allowing to
differ between the two.
Relates #69820
Runtime fields usage is currently reported as part of the xpack feature usage API. Now that runtime fields are part of server, their corresponding stats can be moved to be part of the ordinary mapping stats exposed by the cluster stats API.
Adds support for the include_unloaded_segments flag in node stats, which helps with understanding resource usage of
shared_cache-style searchable snapshots on a per-node basis.
This change adds a new "architectures" section to the
cluster stats, containing a summary of how many nodes
in the cluster are on each processor architecture.
The intention is to make it easier to see whether
clusters are running on aarch64, or mixed x86_64/aarch64,
which may aid support as aarch64 becomes more commonly
used.
Today's network config docs are split into "Network", "HTTP" and
"Transport" pages, with unclear relationships between them. We often
encounter users with weird configs that indicate they don't really
understand how these settings all relate. In fact these pages are all
very interrelated, and the HTTP and Transport pages are almost all only
for advanced users. This commit brings these docs into a single page and
rewords some things to try and guide users away from the advanced
settings unless their configuration needs all the extra complexity.
It also adds a section entitled "Binding and publishing" which clarifies
the meanings of the `bind_host` and `publish_host` parameters. This is
also a common source of confusion amongst users.
It also clarifies that many of these settings accept a list of
addresses, and warns that this may not be what you want. Closes#67956.
Co-authored-by: Adam Locke <adam.locke@elastic.co>
This commit adds statistics about the index creation versions to the `/_cluster/stats` endpoint. The
stats look like:
```
{
"_nodes" : {
"total" : 1,
"successful" : 1,
"failed" : 0
},
"indices" : {
"count" : 3,
...
"versions" : [
{
"version" : "8.0.0",
"index_count" : 1,
"primary_shard_count" : 2,
"total_primary_size" : "8.6kb",
"total_primary_bytes" : 8831
},
{
"version" : "7.11.0",
"index_count" : 1,
"primary_shard_count" : 1,
"total_primary_size" : "4.6kb",
"total_primary_bytes" : 4230
}
]
},
...
}
```
(`total_primary_size` is only shown with the `?human` flag)
This is useful for telemetry as it allows us to see if/when a cluster has indices created on a
previous version that would need to be either upgraded or supported during an upgrade.
We were depending on the BouncyCastle FIPS own mechanics to set
itself in approved only mode since we run with the Security
Manager enabled. The check during startup seems to happen before we
set our restrictive SecurityManager though in
org.elasticsearch.bootstrap.Elasticsearch , and this means that
BCFIPS would not be in approved only mode, unless explicitly
configured so.
This commit sets the appropriate JVM property to explicitly set
BCFIPS in approved only mode in CI and adds tests to ensure that we
will be running with BCFIPS in approved only mode when we expect to.
It also sets xpack.security.fips_mode.enabled to true for all test clusters
used in fips mode and sets the distribution to the default one. It adds a
password to the elasticsearch keystore for all test clusters that run in fips
mode.
Moreover, it changes a few unit tests where we would use bcrypt even in
FIPS 140 mode. These would still pass since we are bundling our own
bcrypt implementation, but are now changed to use FIPS 140 approved
algorithms instead for better coverage.
It also addresses a number of tests that would fail in approved only mode
Mainly:
Tests that use PBKDF2 with a password less than 112 bits (14char). We
elected to change the passwords used everywhere to be at least 14
characters long instead of mandating
the use of pbkdf2_stretch because both pbkdf2 and
pbkdf2_stretch are supported and allowed in fips mode and it makes sense
to test with both. We could possibly figure out the password algorithm used
for each test and adjust password length accordingly only for pbkdf2 but
there is little value in that. It's good practice to use strong passwords so if
our docs and tests use longer passwords, then it's for the best. The approach
is brittle as there is no guarantee that the next test that will be added won't
use a short password, so we add some testing documentation too.
This leaves us with a possible coverage gap since we do support passwords
as short as 6 characters but we only test with > 14 chars but the
validation itself was not tested even before. Tests can be added in a followup,
outside of fips related context.
Tests that use a PKCS12 keystore and were not already muted.
Tests that depend on running test clusters with a basic license or
using the OSS distribution as FIPS 140 support is not available in
neither of these.
Finally, it adds some information around FIPS 140 testing in our testing
documentation reference so that developers can hopefully keep in
mind fips 140 related intricacies when writing/changing docs.
* Clarify that field data cache includes global ordinals
* Describe that the cache should be cleared once the limit is reached
* Clarify that the `_id` field does not supported aggregations anymore
* Fold the `fielddata` mapping parameter page into the `text field docs
* Improve cross-linking
This commit adds the `index.routing.allocation.prefer._tier` setting to the
`DataTierAllocationDecider`. This special-purpose allocation setting lets a user specify a
preference-based list of tiers for an index to be assigned to. For example, if the setting were set
to:
```
"index.routing.allocation.prefer._tier": "data_hot,data_warm,data_content"
```
If the cluster contains any nodes with the `data_hot` role, the decider will only allow them to be
allocated on the `data_hot` node(s). If there are no `data_hot` nodes, but there are `data_warm` and
`data_content` nodes, then the index will be allowed to be allocated on `data_warm` nodes.
This allows us to specify an index's preference for tier(s) without causing the index to be
unassigned if no nodes of a preferred tier are available.
Subsequent work will change the ILM migration to make additional use of this setting.
Relates to #60848
This commit adds the functionality to allocate newly created indices on nodes in the "hot" tier by
default when they are created.
This does not break existing behavior, as nodes with the `data` role are considered to be part of
the hot tier. Users that separate their deployments by using the `data_hot` (and `data_warm`,
`data_cold`, `data_frozen`) roles will have their data allocated on the hot tier nodes now by
default.
This change is a little more complicated than changing the default value for
`index.routing.allocation.include._tier` from null to "data_hot". Instead, this adds the ability to
have a plugin inject a setting into the builder for a newly created index. This has the benefit of
allowing this setting to be visible as part of the settings when retrieving the index, for example:
```
// Create an index
PUT /eggplant
// Get an index
GET /eggplant?flat_settings
```
Returns the default settings now of:
```json
{
"eggplant" : {
"aliases" : { },
"mappings" : { },
"settings" : {
"index.creation_date" : "1597855465598",
"index.number_of_replicas" : "1",
"index.number_of_shards" : "1",
"index.provided_name" : "eggplant",
"index.routing.allocation.include._tier" : "data_hot",
"index.uuid" : "6ySG78s9RWGystRipoBFCA",
"index.version.created" : "8000099"
}
}
}
```
After the initial setting of this setting, it can be treated like any other index level setting.
This new setting is *not* set on a new index if any of the following is true:
- The index is created with an `index.routing.allocation.include.<anything>` setting
- The index is created with an `index.routing.allocation.exclude.<anything>` setting
- The index is created with an `index.routing.allocation.require.<anything>` setting
- The index is created with a null `index.routing.allocation.include._tier` value
- The index was created from an existing source metadata (shrink, clone, split, etc)
Relates to #60848
Transport connections between nodes remain in place until one or other
node shuts down or the connection is disrupted by a flaky network.
Today it is very difficult to demonstrate that transient failures and
cluster instability are caused by the network even though this is often
the case. In particular, transport connections open and close without
logging anything, even at `DEBUG` level, making it very hard to quantify
the scale of the problem or to correlate the networking problems with
external events.
This commit adds the missing `DEBUG`-level logging when transport
connections open and close, and also tracks the total number of
transport connections a node has opened as a measure of the stability of
the underlying network.
Today `GET _nodes/stats/fs` includes `{least,most}_usage_estimate`
fields for some nodes. These fields have rather strange semantics. They
are only reported on the elected master and on nodes that have been the
elected master since they were last restarted; when a node stops being
the elected master these stats remain in place but we stop updating them
so they may become arbitrarily stale.
This means that these statistics are pretty meaningless and impossible
to use correctly. Even if they were kept up to date they're never
reported for data-only nodes anyway, despite the fact that data nodes
are the ones where we care most about disk usage. The information needed
to compute the path with the least/most available space is already
provided in the rest the stats output, so we can treat the inclusion of
these stats as a bug and fix it by simply removing them in this commit.
Since these stats were always optional and mostly omitted (for opaque
reasons) this is not considered a breaking change.
Today the disk-based shard allocator accounts for incoming shards by
subtracting the estimated size of the incoming shard from the free space on the
node. This is an overly conservative estimate if the incoming shard has almost
finished its recovery since in that case it is already consuming most of the
disk space it needs.
This change adds to the shard stats a measure of how much larger each store is
expected to grow, computed from the ongoing recovery, and uses this to account
for the disk usage of incoming shards more accurately.
We document that the cluster state API is an internal representation which may
change, but apparently not emphatically enough. This commit adds a `NOTE:`
admonition to this paragraph.
I see occasional confusion about the explanations emitted by the same-shard
allocation decider, particularly amongst new users setting up a single-node
cluster and trying to determine why their cluster has `yellow` health. For
example:
the shard cannot be allocated to the same node on which a copy of the shard
already exists
This is technically correct but it's quite a complicated sentence. Also, by
starting with "the shard cannot be allocated" it makes it sound like this is
the problem, whereas in fact this message is a good thing and users should
typically focus their attention elsewhere.
This commit simplifies the wording of these messages and makes them sound more
positive, for example:
a copy of this shard is already allocated to this node
* Expose agg usage in Feature Usage API
Counts usage of the aggs and exposes them on the _nodes/usage/.
Closes#53746
* Refactor to include non value sources aggregations
* Fix reported values source type for parent and children aggs
* Refactor SearchModule constructor
* Fix subtype in TTest and IPRanges
* Fix more subtypes in aggs that don't register themselves
* Fix doc tests
* Fix docs
* Fix ScriptedMetricAggregatorTests
* Fix compilation issues after merge
* Fix merge fallout
* This gets stale quickly...
* Address review comments
* Fix tests that were missing proper agg registration in the search module
* Fix ScriptedMetricAggregatorTests
* Address review comments
Co-authored-by: Elastic Machine <elasticmachine@users.noreply.github.com>
PR #51260 moved usage counts about mapping field types and analysis to
the `_cluster/stats` API.
This documents those stats in the response section of the cluster stats
API docs.
The secure_settings_password was never taken into consideration in
the ReloadSecureSettings API. This commit fixes that and adds
necessary REST layer testing. Doing so, it also
- Allows TestClusters to have a password protected keystore
so that it can be set for tests.
- Adds a parameter to the run task so that elastisearch can
be run with a password protected keystore from source.
The use of available processors, the terminology, and the settings
around it have evolved over time. This commit cleans up some places in
the codes and in the docs to adjust to the current terminology.
With this change, when a task is canceled, the task manager will cancel
not only its direct child tasks but all also its descendant tasks.
Closes#50990
Today when canceling a task we broadcast ban/unban requests to all nodes
in the cluster. This strategy does not scale well for hierarchical
cancellation. With this change, we will track outstanding child requests
and broadcast the cancellation to only nodes that have outstanding child
tasks. This change also prevents a parent task from sending child
requests once it got canceled.
Relates #50990
Supersedes #51157
Co-authored-by: Igor Motov <igor@motovs.org>
Co-authored-by: Yannick Welsch <yannick@welsch.lu>
Documents missing data types for several response parameters returned
by the node stats API.
Also adds several missing human-readable parameters returned by the API.
Currently the remote info api has added a number of possible fields
(proxy, num_socket_connections, etc) that are available in proxy mode.
These fields are not aligned with what the settings are named. This
commit modifies this API to align with the settings.
Documents the `nodes` response parameters returned by the
`_cluster/stats` API.
Also adds collapsible attributes for the `indices` and `nodes`
sections.
* Use standard format for reload settings API
The reload-secure-settings API page was not reorganized for the standard
API format, so this commit is reorganizing the page and adding some
links to the page in related documentation.
* Fix broken links
* Reorder examples to correctly check API response
* Note that only certain settings are reloadable
* [DOCS] Edits layout
* [DOCS] Removes unnecessary callouts
Co-authored-by: Lisa Cawley <lcawley@elastic.co>
* Reload secure settings with password (#43197)
If a password is not set, we assume an empty string to be
compatible with previous behavior.
Only allow the reload to be broadcast to other nodes if TLS is
enabled for the transport layer.
* Add passphrase support to elasticsearch-keystore (#38498)
This change adds support for keystore passphrases to all subcommands
of the elasticsearch-keystore cli tool and adds a subcommand for
changing the passphrase of an existing keystore.
The work to read the passphrase in Elasticsearch when
loading, which will be addressed in a different PR.
Subcommands of elasticsearch-keystore can handle (open and create)
passphrase protected keystores
When reading a keystore, a user is only prompted for a passphrase
only if the keystore is passphrase protected.
When creating a keystore, a user is allowed (default behavior) to create one with an
empty passphrase
Passphrase can be set to be empty when changing/setting it for an
existing keystore
Relates to: #32691
Supersedes: #37472
* Restore behavior for force parameter (#44847)
Turns out that the behavior of `-f` for the add and add-file sub
commands where it would also forcibly create the keystore if it
didn't exist, was by design - although undocumented.
This change restores that behavior auto-creating a keystore that
is not password protected if the force flag is used. The force
OptionSpec is moved to the BaseKeyStoreCommand as we will presumably
want to maintain the same behavior in any other command that takes
a force option.
* Handle pwd protected keystores in all CLI tools (#45289)
This change ensures that `elasticsearch-setup-passwords` and
`elasticsearch-saml-metadata` can handle a password protected
elasticsearch.keystore.
For setup passwords the user would be prompted to add the
elasticsearch keystore password upon running the tool. There is no
option to pass the password as a parameter as we assume the user is
present in order to enter the desired passwords for the built-in
users.
For saml-metadata, we prompt for the keystore password at all times
even though we'd only need to read something from the keystore when
there is a signing or encryption configuration.
* Modify docs for setup passwords and saml metadata cli (#45797)
Adds a sentence in the documentation of `elasticsearch-setup-passwords`
and `elasticsearch-saml-metadata` to describe that users would be
prompted for the keystore's password when running these CLI tools,
when the keystore is password protected.
Co-Authored-By: Lisa Cawley <lcawley@elastic.co>
* Elasticsearch keystore passphrase for startup scripts (#44775)
This commit allows a user to provide a keystore password on Elasticsearch
startup, but only prompts when the keystore exists and is encrypted.
The entrypoint in Java code is standard input. When the Bootstrap class is
checking for secure keystore settings, it checks whether or not the keystore
is encrypted. If so, we read one line from standard input and use this as the
password. For simplicity's sake, we allow a maximum passphrase length of 128
characters. (This is an arbitrary limit and could be increased or eliminated.
It is also enforced in the keystore tools, so that a user can't create a
password that's too long to enter at startup.)
In order to provide a password on standard input, we have to account for four
different ways of starting Elasticsearch: the bash startup script, the Windows
batch startup script, systemd startup, and docker startup. We use wrapper
scripts to reduce systemd and docker to the bash case: in both cases, a
wrapper script can read a passphrase from the filesystem and pass it to the
bash script.
In order to simplify testing the need for a passphrase, I have added a
has-passwd command to the keystore tool. This command can run silently, and
exit with status 0 when the keystore has a password. It exits with status 1 if
the keystore doesn't exist or exists and is unencrypted.
A good deal of the code-change in this commit has to do with refactoring
packaging tests to cleanly use the same tests for both the "archive" and the
"package" cases. This required not only moving tests around, but also adding
some convenience methods for an abstraction layer over distribution-specific
commands.
* Adjust docs for password protected keystore (#45054)
This commit adds relevant parts in the elasticsearch-keystore
sub-commands reference docs and in the reload secure settings API
doc.
* Fix failing Keystore Passphrase test for feature branch (#50154)
One problem with the passphrase-from-file tests, as written, is that
they would leave a SystemD environment variable set when they failed,
and this setting would cause elasticsearch startup to fail for other
tests as well. By using a try-finally, I hope that these tests will fail
more gracefully.
It appears that our Fedora and Ubuntu environments may be configured to
store journald information under /var rather than under /run, so that it
will persist between boots. Our destructive tests that read from the
journal need to account for this in order to avoid trying to limit the
output we check in tests.
* Run keystore management tests on docker distros (#50610)
* Add Docker handling to PackagingTestCase
Keystore tests need to be able to run in the Docker case. We can do this
by using a DockerShell instead of a plain Shell when Docker is running.
* Improve ES startup check for docker
Previously we were checking truncated output for the packaged JDK as
an indication that Elasticsearch had started. With new preliminary
password checks, we might get a false positive from ES keystore
commands, so we have to check specifically that the Elasticsearch
class from the Bootstrap package is what's running.
* Test password-protected keystore with Docker (#50803)
This commit adds two tests for the case where we mount a
password-protected keystore into a Docker container and provide a
password via a Docker environment variable.
We also fix a logging bug where we were logging the identifier for an
array of strings rather than the contents of that array.
* Add documentation for keystore startup prompting (#50821)
When a keystore is password-protected, Elasticsearch will prompt at
startup. This commit adds documentation for this prompt for the archive,
systemd, and Docker cases.
Co-authored-by: Lisa Cawley <lcawley@elastic.co>
* Warn when unable to upgrade keystore on debian (#51011)
For Red Hat RPM upgrades, we warn if we can't upgrade the keystore. This
commit brings the same logic to the code for Debian packages. See the
posttrans file for gets executed for RPMs.
* Restore handling of string input
Adds tests that were mistakenly removed. One of these tests proved
we were not handling the the stdin (-x) option correctly when no
input was added. This commit restores the original approach of
reading stdin one char at a time until there is no more (-1, \r, \n)
instead of using readline() that might return null
* Apply spotless reformatting
* Use '--since' flag to get recent journal messages
When we get Elasticsearch logs from journald, we want to fetch only log
messages from the last run. There are two reasons for this. First, if
there are many logs, we might get a string that's too large for our
utility methods. Second, when we're looking for a specific message or
error, we almost certainly want to look only at messages from the last
execution.
Previously, we've been trying to do this by clearing out the physical
files under the journald process. But there seems to be some contention
over these directories: if journald writes a log file in between when
our deletion command deletes the file and when it deletes the log
directory, the deletion will fail.
It seems to me that we might be able to use journald's "--since" flag to
retrieve only log messages from the last run, and that this might be
less likely to fail due to race conditions in file deletion.
Unfortunately, it looks as if the "--since" flag has a granularity of
one-second. I've added a two-second sleep to make sure that there's a
sufficient gap between the test that will read from journald and the
test before it.
* Use new journald wrapper pattern
* Update version added in secure settings request
Co-authored-by: Lisa Cawley <lcawley@elastic.co>
Co-authored-by: Ioannis Kakavas <ikakavas@protonmail.com>
elastic/docs#1687 added support for the `[%collapsible]` Asciidoc
attribute, which creates collapsible sections in the HTML output.
This PR makes two related changes to the nodes stats API documentation:
* Makes the response parameter sections collapsible. This allows users
to more easily navigate the page without long walls of text.
* Reorders the response parameter sections to match the default order
returned by the API.
Relates to #47524.
Updates several example snippets in the Cluster Allocation Explain API
docs to consistently use the `my_index` index.
Previously, the snippets switches from `my_index` to `idx`, which could
confuse users.
Co-authored-by: Emmanuel DEMEY <demey.emmanuel@gmail.com>
Co-authored-by: Emmanuel DEMEY <demey.emmanuel@gmail.com>