199 lines
8.1 KiB
Plaintext
199 lines
8.1 KiB
Plaintext
[[modules-discovery-settings]]
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=== Discovery and cluster formation settings
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Discovery and cluster formation are affected by the following settings:
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`discovery.seed_hosts`::
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Provides a list of master-eligible nodes in the cluster. Each value has the
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format `host:port` or `host`, where `port` defaults to the setting
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`transport.profiles.default.port`. Note that IPv6 hosts must be bracketed.
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The default value is `["127.0.0.1", "[::1]"]`. See <<unicast.hosts>>. This
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setting was previously known as `discovery.zen.ping.unicast.hosts`. Its old
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name is deprecated but continues to work in order to preserve backwards
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compatibility. Support for the old name will be removed in a future
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version.
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`discovery.seed_providers`::
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Specifies which types of <<built-in-hosts-providers,seed hosts provider>>
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to use to obtain the addresses of the seed nodes used to start the
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discovery process. By default, it is the
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<<settings-based-hosts-provider,settings-based seed hosts provider>>. This
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setting was previously known as `discovery.zen.hosts_provider`. Its old
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name is deprecated but continues to work in order to preserve backwards
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compatibility. Support for the old name will be removed in a future
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version.
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`discovery.cluster_formation_warning_timeout`::
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Sets how long a node will try to form a cluster before logging a warning
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that the cluster did not form. Defaults to `10s`. If a cluster has not
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formed after `discovery.cluster_formation_warning_timeout` has elapsed then
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the node will log a warning message that starts with the phrase `master not
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discovered` which describes the current state of the discovery process.
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`discovery.find_peers_interval`::
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Sets how long a node will wait before attempting another discovery round.
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Defaults to `1s`.
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`discovery.probe.connect_timeout`::
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Sets how long to wait when attempting to connect to each address. Defaults
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to `3s`.
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`discovery.probe.handshake_timeout`::
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Sets how long to wait when attempting to identify the remote node via a
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handshake. Defaults to `1s`.
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`discovery.request_peers_timeout`::
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Sets how long a node will wait after asking its peers again before
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considering the request to have failed. Defaults to `3s`.
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`discovery.seed_resolver.max_concurrent_resolvers`::
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Specifies how many concurrent DNS lookups to perform when resolving the
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addresses of seed nodes. Defaults to `10`. This setting was previously
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known as `discovery.zen.ping.unicast.concurrent_connects`. Its old name is
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deprecated but continues to work in order to preserve backwards
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compatibility. Support for the old name will be removed in a future
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version.
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`discovery.seed_resolver.timeout`::
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Specifies how long to wait for each DNS lookup performed when resolving the
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addresses of seed nodes. Defaults to `5s`. This setting was previously
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known as `discovery.zen.ping.unicast.hosts.resolve_timeout`. Its old name
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is deprecated but continues to work in order to preserve backwards
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compatibility. Support for the old name will be removed in a future
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version.
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`cluster.auto_shrink_voting_configuration`::
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Controls whether the <<modules-discovery-voting,voting configuration>>
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sheds departed nodes automatically, as long as it still contains at least 3
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nodes. The default value is `true`. If set to `false`, the voting
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configuration never shrinks automatically and you must remove departed
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nodes manually with the <<voting-config-exclusions,voting configuration
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exclusions API>>.
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[[master-election-settings]]`cluster.election.back_off_time`::
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Sets the amount to increase the upper bound on the wait before an election
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on each election failure. Note that this is _linear_ backoff. This defaults
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to `100ms`
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`cluster.election.duration`::
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Sets how long each election is allowed to take before a node considers it to
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have failed and schedules a retry. This defaults to `500ms`.
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`cluster.election.initial_timeout`::
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Sets the upper bound on how long a node will wait initially, or after the
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elected master fails, before attempting its first election. This defaults
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to `100ms`.
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`cluster.election.max_timeout`::
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Sets the maximum upper bound on how long a node will wait before attempting
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an first election, so that an network partition that lasts for a long time
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does not result in excessively sparse elections. This defaults to `10s`
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[[fault-detection-settings]]`cluster.fault_detection.follower_check.interval`::
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Sets how long the elected master waits between follower checks to each
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other node in the cluster. Defaults to `1s`.
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`cluster.fault_detection.follower_check.timeout`::
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Sets how long the elected master waits for a response to a follower check
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before considering it to have failed. Defaults to `10s`.
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`cluster.fault_detection.follower_check.retry_count`::
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Sets how many consecutive follower check failures must occur to each node
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before the elected master considers that node to be faulty and removes it
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from the cluster. Defaults to `3`.
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`cluster.fault_detection.leader_check.interval`::
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Sets how long each node waits between checks of the elected master.
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Defaults to `1s`.
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`cluster.fault_detection.leader_check.timeout`::
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Sets how long each node waits for a response to a leader check from the
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elected master before considering it to have failed. Defaults to `10s`.
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`cluster.fault_detection.leader_check.retry_count`::
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Sets how many consecutive leader check failures must occur before a node
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considers the elected master to be faulty and attempts to find or elect a
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new master. Defaults to `3`.
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`cluster.follower_lag.timeout`::
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Sets how long the master node waits to receive acknowledgements for cluster
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state updates from lagging nodes. The default value is `90s`. If a node does
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not successfully apply the cluster state update within this period of time,
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it is considered to have failed and is removed from the cluster. See
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<<cluster-state-publishing>>.
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`cluster.initial_master_nodes`::
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Sets a list of the <<node.name,node names>> or transport addresses of the
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initial set of master-eligible nodes in a brand-new cluster. By default
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this list is empty, meaning that this node expects to join a cluster that
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has already been bootstrapped. See <<initial_master_nodes>>.
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`cluster.join.timeout`::
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Sets how long a node will wait after sending a request to join a cluster
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before it considers the request to have failed and retries. Defaults to
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`60s`.
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`cluster.max_voting_config_exclusions`::
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Sets a limit on the number of voting configuration exclusions at any one
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time. The default value is `10`. See
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<<modules-discovery-adding-removing-nodes>>.
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`cluster.publish.timeout`::
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Sets how long the master node waits for each cluster state update to be
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completely published to all nodes. The default value is `30s`. If this
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period of time elapses, the cluster state change is rejected. See
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<<cluster-state-publishing>>.
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[[no-master-block]]`cluster.no_master_block`::
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Specifies which operations are rejected when there is no active master in a
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cluster. This setting has two valid values:
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+
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--
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`all`::: All operations on the node (both read and write operations) are rejected.
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This also applies for API cluster state read or write operations, like the get
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index settings, put mapping and cluster state API.
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`write`::: (default) Write operations are rejected. Read operations succeed,
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based on the last known cluster configuration. This situation may result in
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partial reads of stale data as this node may be isolated from the rest of the
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cluster.
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[NOTE]
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===============================
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* The `cluster.no_master_block` setting doesn't apply to nodes-based APIs
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(for example, cluster stats, node info, and node stats APIs). Requests to these
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APIs are not be blocked and can run on any available node.
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* For the cluster to be fully operational, it must have an active master.
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===============================
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WARNING: This setting replaces the `discovery.zen.no_master_block` setting in
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earlier versions. The `discovery.zen.no_master_block` setting is ignored.
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--
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