[role="xpack"]
[testenv="platinum"]
[[ccr-getting-started]]
== Getting started with {ccr}

beta[]

This getting-started guide for {ccr} shows you how to:

* <<ccr-getting-started-remote-cluster,Connect a local cluster to a remote
  cluster>>
* <<ccr-getting-started-leader-index,Create a leader index>> in a remote cluster
* <<ccr-getting-started-follower-index,Create a follower index>> that replicates
  a leader index
* <<ccr-getting-started-auto-follow,Automatically create follower indices>>

[float]
[[ccr-getting-started-before-you-begin]]
=== Before you begin
. {stack-gs}/get-started-elastic-stack.html#install-elasticsearch[Install {es}]
  on your local and remote clusters.

. Obtain a license that includes the {ccr} features. See
  https://www.elastic.co/subscriptions[subscriptions] and
  <<license-management>>.

. If the Elastic {security-features} are enabled in your local and remote
  clusters, you need a user that has appropriate authority to perform the steps
  in this tutorial.
+
--
[[ccr-getting-started-security]]
The {ccr} features use cluster privileges and built-in roles to make it easier
to control which users have authority to manage {ccr}.

By default, you can perform all of the steps in this tutorial by
using the built-in `elastic` user. However, a password must be set for this user
before the user can do anything. For information about how to set that password,
see <<security-getting-started>>.

If you are performing these steps in a production environment, take extra care
because the `elastic` user has the `superuser` role and you could inadvertently
make significant changes.

Alternatively, you can assign the appropriate privileges to a user ID of your
choice. On the remote cluster that contains the leader index, a user will need
the `read_ccr` cluster privilege and `monitor` and `read` privileges on the
leader index.

[source,yml]
--------------------------------------------------
ccr_user:
  cluster:
    - read_ccr
  indices:
    - names: [ 'leader-index' ]
      privileges:
        - monitor
        - read
--------------------------------------------------

On the local cluster that contains the follower index, the same user will need
the `manage_ccr` cluster privilege and `monitor`, `read`, `write` and
`manage_follow_index` privileges on the follower index.

[source,yml]
--------------------------------------------------
ccr_user:
  cluster:
    - manage_ccr
  indices:
    - names: [ 'follower-index' ]
      privileges:
        - monitor
        - read
        - write
        - manage_follow_index
--------------------------------------------------

If you are managing
<<ccr-getting-started-remote-cluster,connecting to the remote cluster>> via the
cluster update settings API, you will also need a user with the `all` cluster
privilege.
--

[float]
[[ccr-getting-started-remote-cluster]]
=== Connecting to a remote cluster

The {ccr} features require that you
{ref}/modules-remote-clusters.html[connect your local cluster to a remote
cluster]. In this tutorial, we will connect our local cluster to a remote
cluster with the cluster alias `leader`.

[source,js]
--------------------------------------------------
PUT /_cluster/settings
{
  "persistent" : {
    "cluster" : {
      "remote" : {
        "leader" : {
          "seeds" : [
            "127.0.0.1:9300" <1>
          ]
        }
      }
    }
  }
}
--------------------------------------------------
// CONSOLE
// TEST[setup:host]
// TEST[s/127.0.0.1:9300/\${transport_host}/]
<1> Specifies the hostname and transport port of a seed node in the remote
    cluster.

You can verify that the local cluster is successfully connected to the remote
cluster.

[source,js]
--------------------------------------------------
GET /_remote/info
--------------------------------------------------
// CONSOLE
// TEST[continued]

The API will respond by showing that the local cluster is connected to the
remote cluster.

[source,js]
--------------------------------------------------
{
  "leader" : {
    "seeds" : [
      "127.0.0.1:9300"
    ],
    "connected" : true, <1>
    "num_nodes_connected" : 1, <2>
    "max_connections_per_cluster" : 3,
    "initial_connect_timeout" : "30s",
    "skip_unavailable" : false
  }
}
--------------------------------------------------
// TESTRESPONSE
// TEST[s/127.0.0.1:9300/$body.leader.seeds.0/]
// TEST[s/"connected" : true/"connected" : $body.leader.connected/]
// TEST[s/"num_nodes_connected" : 1/"num_nodes_connected" : $body.leader.num_nodes_connected/]
<1> This shows the local cluster is connected to the remote cluster with cluster
    alias `leader`
<2> This shows the number of nodes in the remote cluster the local cluster is
    connected to.
    
Alternatively, you can manage remote clusters on the
*Management / Elasticsearch / Remote Clusters* page in {kib}:

[role="screenshot"]
image::ml/images/remote-clusters.jpg["The Remote Clusters page in {kib}"]


[float]
[[ccr-getting-started-leader-index]]
=== Creating a leader index

Leader indices require a special index setting to ensure that the operations
that need to be replicated are available when the follower requests them from
the leader. This setting is used to control how many soft deletes are retained.
A _soft delete_ occurs whenever a document is deleted or updated. Soft deletes
can be enabled only on new indices created on or after {es} 6.5.0, and enabled
by default on new indices created on or after {es} 7.0.0.

In the following example, we will create a leader index in the remote cluster:

[source,js]
--------------------------------------------------
PUT /server-metrics
{
  "settings" : {
    "index" : {
      "number_of_shards" : 1,
      "number_of_replicas" : 0,
      "soft_deletes" : {
        "retention" : {
          "operations" : 1024 <1>
        }
      }
    }
  },
  "mappings" : {
    "properties" : {
      "@timestamp" : {
        "type" : "date"
      },
      "accept" : {
        "type" : "long"
      },
      "deny" : {
        "type" : "long"
      },
      "host" : {
        "type" : "keyword"
      },
      "response" : {
        "type" : "float"
      },
      "service" : {
        "type" : "keyword"
      },
      "total" : {
        "type" : "long"
      }
    }
  }
}
--------------------------------------------------
// CONSOLE
// TEST[continued]
<1> Sets that up to 1024 soft deletes will be retained.

[float]
[[ccr-getting-started-follower-index]]
=== Creating a follower index

Follower indices are created with the {ref}/ccr-put-follow.html[create follower
API]. When you create a follower index, you must reference the
<<ccr-getting-started-remote-cluster,remote cluster>> and the
<<ccr-getting-started-leader-index,leader index>> that you created in the remote
cluster.

[source,js]
--------------------------------------------------
PUT /server-metrics-copy/_ccr/follow
{
  "remote_cluster" : "leader",
  "leader_index" : "server-metrics"
}
--------------------------------------------------
// CONSOLE
// TEST[continued]

//////////////////////////

[source,js]
--------------------------------------------------
{
  "follow_index_created" : true,
  "follow_index_shards_acked" : true,
  "index_following_started" : true
}
--------------------------------------------------
// TESTRESPONSE

//////////////////////////

Now when you index documents into your leader index, you will see these
documents replicated in the follower index. You can
inspect the status of replication using the
{ref}/ccr-get-follow-stats.html[get follower stats API].

//////////////////////////

[source,js]
--------------------------------------------------
POST /server-metrics-copy/_ccr/pause_follow

POST /server-metrics-copy/_close

POST /server-metrics-copy/_ccr/unfollow
--------------------------------------------------
// CONSOLE
// TEST[continued]

//////////////////////////

[float]
[[ccr-getting-started-auto-follow]]
=== Automatically create follower indices

The <<ccr-auto-follow,auto-follow>> feature in {ccr} helps for time series use
cases where you want to follow new indices that are periodically created in the
remote cluster (such as daily Beats indices). Auto-following is configured using
the {ref}/ccr-put-auto-follow-pattern.html[create auto-follow pattern API]. With
an auto-follow pattern, you reference the
<<ccr-getting-started-remote-cluster,remote cluster>> that you connected your
local cluster to. You must also specify a collection of  patterns that match the
indices you want to automatically follow.

For example:

[source,js]
--------------------------------------------------
PUT /_ccr/auto_follow/beats
{
  "remote_cluster" : "leader",
  "leader_index_patterns" :
  [
    "metricbeat-*", <1>
    "packetbeat-*" <2>
  ],
  "follow_index_pattern" : "{{leader_index}}-copy" <3>
}
--------------------------------------------------
// CONSOLE
// TEST[continued]
<1> Automatically follow new {metricbeat} indices.
<2> Automatically follow new {packetbeat} indices.
<3> The name of the follower index is derived from the name of the leader index
    by adding the suffix `-copy` to the name of the leader index.

//////////////////////////

[source,js]
--------------------------------------------------
{
  "acknowledged" : true
}
--------------------------------------------------
// TESTRESPONSE

//////////////////////////

//////////////////////////

[source,js]
--------------------------------------------------
DELETE /_ccr/auto_follow/beats
--------------------------------------------------
// CONSOLE
// TEST[continued]

//////////////////////////

Alternatively, you can manage auto-follow patterns on the
*Management / Elasticsearch / Cross Cluster Replication* page in {kib}:

[role="screenshot"]
image::ml/images/auto-follow-patterns.jpg["The Auto-follow patterns page in {kib}"]
