[DOCS] Reformats cluster health and cluster state APIs (#45206)

Co-Authored-By: James Rodewig <james.rodewig@elastic.co>

docs/reference/cluster/health.asciidoc

@@ -1,9 +1,141 @@
 [[cluster-health]]
 === Cluster Health
 
-The cluster health API allows to get a very simple status on the health
-of the cluster. For example, on a quiet single node cluster with a single index
-with one shard and one replica, this:
+Returns the health status of a cluster.
+
+[[cluster-health-api-request]]
+==== {api-request-title}
+
+`GET _cluster/health/{index}`
+
+[[cluster-health-api-desc]]
+==== {api-description-title}
+
+The cluster health API returns a simple status on the health of the 
+cluster. The API can also be executed against one or more indices to get just 
+the specified indices health.
+
+The cluster health status is: `green`, `yellow` or `red`. On the shard level, a 
+`red` status indicates that the specific shard is not allocated in the cluster, 
+`yellow` means that the primary shard is allocated but replicas are not, and 
+`green` means that all shards are allocated. The index level status is 
+controlled by the worst shard status. The cluster status is controlled by the 
+worst index status.
+
+One of the main benefits of the API is the ability to wait until the cluster 
+reaches a certain high water-mark health level. For example, the following will 
+wait for 50 seconds for the cluster to reach the `yellow` level (if it reaches 
+the `green` or `yellow` status before 50 seconds elapse, it will return at that 
+point):
+
+[source,js]
+--------------------------------------------------
+GET /_cluster/health?wait_for_status=yellow&timeout=50s
+--------------------------------------------------
+// CONSOLE
+
+[[cluster-health-api-path-params]]
+==== {api-path-parms-title}
+
+include::{docdir}/rest-api/common-parms.asciidoc[tag=index]
+
+[[cluster-health-api-query-params]]
+==== {api-query-parms-title}
+
+`level`::
+    (Optional, string) Can be one of `cluster`, `indices` or `shards`. Controls 
+    the details level of the health information returned. Defaults to `cluster`.
+    
+include::{docdir}/rest-api/common-parms.asciidoc[tag=local]
+    
+include::{docdir}/rest-api/common-parms.asciidoc[tag=timeoutparms]
+
+`wait_for_active_shards`::
+    (Optional, string) A number controlling to how many active shards to wait 
+    for, `all` to wait for all shards in the cluster to be active, or `0` to not 
+    wait. Defaults to `0`.
+    
+`wait_for_events`::
+    (Optional, string) Can be one of `immediate`, `urgent`, `high`, `normal`, 
+    `low`, `languid`. Wait until all currently queued events with the given 
+    priority are processed.
+
+`wait_for_no_initializing_shards`::
+    (Optional, boolean) A boolean value which controls whether to wait (until 
+    the timeout provided) for the cluster to have no shard initializations. 
+    Defaults to false, which means it will not wait for initializing shards.
+
+`wait_for_no_relocating_shards`::
+    (Optional, boolean) A boolean value which controls whether to wait (until 
+    the timeout provided) for the cluster to have no shard relocations. Defaults 
+    to false, which means it will not wait for relocating shards.
+
+`wait_for_nodes`::
+    (Optional, string) The request waits until the specified number `N` of
+    nodes is available. It also accepts `>=N`, `<=N`, `>N` and `<N`.
+    Alternatively, it is possible to use `ge(N)`, `le(N)`, `gt(N)` and
+    `lt(N)` notation.
+
+`wait_for_status`::
+    (Optional, string) One of `green`, `yellow` or `red`. Will wait (until the 
+    timeout provided) until the status of the cluster changes to the one
+    provided or better, i.e. `green` > `yellow` > `red`. By default, will not
+    wait for any status.
+
+[[cluster-health-api-response-body]]
+==== {api-response-body-title}
+
+`cluster_name`::
+    (string) The name of the cluster.
+
+`status`::
+    (string) The health status of the cluster.
+
+`timed_out`::
+    (boolean) If `false` the response returned within the period of 
+    time that is specified by the `timeout` parameter (`30s` by default).
+
+`number_of_nodes`::
+    (integer) The number of nodes within the cluster.
+
+`number_of_data_nodes`::
+    (integer) The number of nodes that are dedicated data nodes.
+
+`active_primary_shards`::
+    (integer) The number of active primary shards.
+
+`active_shards`::
+    (integer) The total number of active primary and replica shards.
+
+`relocating_shards`::
+    (integer) The number of shards that are under relocation.
+
+`initializing_shards`::
+    (integer) The number of shards that are under initialization.
+
+`unassigned_shards`::
+    (integer) The number of shards that are not allocated.
+
+`delayed_unassigned_shards`::
+    (integer) The number of shards whose allocation has been delayed by the 
+    timeout settings.
+
+`number_of_pending_tasks`::
+    (integer) The number of cluster-level changes that have not yet been 
+    executed.
+
+`number_of_in_flight_fetch`::
+    (integer) The number of unfinished fetches.
+
+`task_max_waiting_in_queue_millis`::
+    (integer) The time expressed in milliseconds since the earliest initiated task 
+    is waiting for being performed.
+
+`active_shards_percent_as_number`::
+    (float) The ratio of active shards in the cluster expressed as a percentage. 
+
+[[cluster-health-api-example]]
+==== {api-examples-title}
 
 [source,js]
 --------------------------------------------------
@@ -12,7 +144,8 @@ GET _cluster/health
 // CONSOLE
 // TEST[s/^/PUT test1\n/]
 
-Returns this:
+The API returns the following response in case of a quiet single node cluster 
+with a single index with one shard and one replica:
 
 [source,js]
 --------------------------------------------------
@@ -38,90 +171,6 @@ Returns this:
 // TESTRESPONSE[s/"number_of_pending_tasks" : 0,/"number_of_pending_tasks" : $body.number_of_pending_tasks,/]
 // TESTRESPONSE[s/"task_max_waiting_in_queue_millis": 0/"task_max_waiting_in_queue_millis": $body.task_max_waiting_in_queue_millis/]
 
-
-The API can also be executed against one or more indices to get just the
-specified indices health:
-
-[source,js]
---------------------------------------------------
-GET /_cluster/health/test1,test2
---------------------------------------------------
-// CONSOLE
-// TEST[s/^/PUT test1\nPUT test2\n/]
-
-The cluster health status is: `green`, `yellow` or `red`. On the shard
-level, a `red` status indicates that the specific shard is not allocated
-in the cluster, `yellow` means that the primary shard is allocated but
-replicas are not, and `green` means that all shards are allocated. The
-index level status is controlled by the worst shard status. The cluster
-status is controlled by the worst index status.
-
-One of the main benefits of the API is the ability to wait until the
-cluster reaches a certain high water-mark health level. For example, the
-following will wait for 50 seconds for the cluster to reach the `yellow`
-level (if it reaches the `green` or `yellow` status before 50 seconds elapse,
-it will return at that point):
-
-[source,js]
---------------------------------------------------
-GET /_cluster/health?wait_for_status=yellow&timeout=50s
---------------------------------------------------
-// CONSOLE
-
-[float]
-[[request-params]]
-==== Request Parameters
-
-The cluster health API accepts the following request parameters:
-
-`level`::
-    Can be one of `cluster`, `indices` or `shards`. Controls the
-    details level of the health information returned. Defaults to `cluster`.
-
-`wait_for_status`::
-    One of `green`, `yellow` or `red`. Will wait (until
-    the timeout provided) until the status of the cluster changes to the one
-    provided or better, i.e. `green` > `yellow` > `red`. By default, will not
-    wait for any status.
-
-`wait_for_no_relocating_shards`::
-    A boolean value which controls whether to wait (until the timeout provided)
-    for the cluster to have no shard relocations. Defaults to false, which means
-    it will not wait for relocating shards.
-
-`wait_for_no_initializing_shards`::
-    A boolean value which controls whether to wait (until the timeout provided)
-    for the cluster to have no shard initializations. Defaults to false, which means
-    it will not wait for initializing shards.
-
-`wait_for_active_shards`::
-    A number controlling to how many active shards to wait for, `all` to wait
-    for all shards in the cluster to be active, or `0` to not wait. Defaults to `0`.
-
-`wait_for_nodes`::
-    The request waits until the specified number `N` of
-    nodes is available. It also accepts `>=N`, `<=N`, `>N` and `<N`.
-    Alternatively, it is possible to use `ge(N)`, `le(N)`, `gt(N)` and
-    `lt(N)` notation.
-
-`wait_for_events`::
-    Can be one of `immediate`, `urgent`, `high`, `normal`, `low`, `languid`.
-    Wait until all currently queued events with the given priority are processed.
-
-`timeout`::
-    A time based parameter controlling how long to wait if one of
-    the wait_for_XXX are provided. Defaults to `30s`.
-
-`master_timeout`::
-    A time based parameter controlling how long to wait if the master has not been
-    discovered yet or disconnected.
-    If not provided, uses the same value as `timeout`.
-
-`local`::
-    If `true` returns the local node information and does not provide
-    the state from master node. Default: `false`.
-
-
 The following is an example of getting the cluster health at the
 `shards` level:
 

docs/reference/cluster/state.asciidoc

@@ -1,6 +1,16 @@
 [[cluster-state]]
 === Cluster State
 
+Returns metadata about the state of the cluster.
+
+[[cluster-state-api-request]]
+==== {api-request-title}
+
+`GET /_cluster/state/{metrics}/{index}`
+
+[[cluster-state-api-desc]]
+==== {api-description-title}
+
 The cluster state API allows access to metadata representing the state of the
 whole cluster. This includes information such as
 
@@ -11,19 +21,13 @@ whole cluster. This includes information such as
 * information about the indices in the cluster, including their mappings and
   settings
 
-* the locations of all the shards in the cluster
+* the locations of all the shards in the cluster.
 
 The response is an internal representation of the cluster state and its format
 may change from version to version. If possible, you should obtain any
 information from the cluster state using the other, more stable,
 <<cluster,cluster APIs>>.
 
-[source,js]
---------------------------------------------------
-GET /_cluster/state
---------------------------------------------------
-// CONSOLE
-
 The response provides the cluster state itself, which can be filtered to only
 retrieve the parts of interest as described below.
 
@@ -38,47 +42,84 @@ that the latest cluster state is returned. For debugging purposes, you can
 retrieve the cluster state local to a particular node by adding `local=true` to
 the query string.
 
-[float]
-==== Response Filters
+[[cluster-state-api-path-params]]
+==== {api-path-parms-title}
 
 The cluster state contains information about all the indices in the cluster,
 including their mappings, as well as templates and other metadata. This means it
 can sometimes be quite large. To avoid the need to process all this information
 you can request only the part of the cluster state that you need:
 
-[source,js]
---------------------------------------------------
-GET /_cluster/state/{metrics}
-GET /_cluster/state/{metrics}/{indices}
---------------------------------------------------
-// CONSOLE
-
-`{metrics}` is a comma-separated list of the following options.
-
-`version`::
-    Shows the cluster state version.
-
-`master_node`::
-    Shows the elected `master_node` part of the response
-
-`nodes`::
-    Shows the `nodes` part of the response
-
-`routing_table`::
-    Shows the `routing_table` part of the response. If you supply a comma
-    separated list of indices, the returned output will only contain the routing
-    table for these indices.
-
-`metadata`::
-    Shows the `metadata` part of the response. If you supply a comma separated
-    list of indices, the returned output will only contain metadata for these
-    indices.
-
-`blocks`::
-    Shows the `blocks` part of the response.
-
-`_all`::
-    Shows all metrics.
+`{metrics}`::
+    (Optional, string) A comma-separated list of the following options:
++
+--
+  `_all`::
+      Shows all metrics.
+    
+  `blocks`::
+      Shows the `blocks` part of the response.
+
+  `master_node`::
+      Shows the elected `master_node` part of the response.
+    
+  `metadata`::
+      Shows the `metadata` part of the response. If you supply a comma separated
+      list of indices, the returned output will only contain metadata for these
+      indices.
+
+  `nodes`::
+      Shows the `nodes` part of the response.
+
+  `routing_nodes`::
+      Shows the `routing_nodes` part of the response.
+
+  `routing_table`::
+      Shows the `routing_table` part of the response. If you supply a comma
+      separated list of indices, the returned output will only contain the 
+      routing table for these indices.
+    
+  `version`::
+      Shows the cluster state version.
+--
+
+include::{docdir}/rest-api/common-parms.asciidoc[tag=index]
+
+
+[[cluster-state-api-query-params]]
+==== {api-query-parms-title}
+
+`allow_no_indices`::
+    (Optional, boolean) If `true`, the wildcard indices expression that resolves 
+    into no concrete indices will be ignored. (This includes `_all` string or 
+    when no indices have been specified).
+
+`expand_wildcards`::
+    (Optional, string) Whether to expand wildcard expression to concrete indices 
+    that are open, closed or both. Available options: `open`, `closed`, `none`, 
+    `all`.
+
+include::{docdir}/rest-api/common-parms.asciidoc[tag=flat-settings]
+    
+`ignore_unavailable`::
+    (Optional, boolean) If `true`, unavailable indices (missing or closed) will 
+    be ignored.
+
+include::{docdir}/rest-api/common-parms.asciidoc[tag=local]
+
+include::{docdir}/rest-api/common-parms.asciidoc[tag=master-timeout]
+
+`wait_for_metadata_version`::
+    (Optional, integer) Waits for the metadata version to be equal or greater 
+    than the specified metadata version.
+    
+`wait_for_timeout`::
+    (Optional, <<time-units, time units>>) Specifies the maximum time to wait 
+    for wait_for_metadata_version before timing out.
+
+
+[[cluster-state-api-example]]
+==== {api-examples-title}
 
 The following example returns only `metadata` and `routing_table` data for the
 `foo` and `bar` indices:
@@ -97,7 +138,7 @@ GET /_cluster/state/_all/foo,bar
 --------------------------------------------------
 // CONSOLE
 
-Finally, this example return only the `blocks` metadata:
+This example returns only the `blocks` metadata:
 
 [source,js]
 --------------------------------------------------