Discovery and cluster formation settings
editDiscovery and cluster formation settings
editDiscovery and cluster formation are affected by the following settings:
-
discovery.seed_hosts
-
(Static) Provides a list of the addresses of the master-eligible nodes in the cluster. May also be a single string containing the addresses separated by commas. Each address has the format
host:port
orhost
. Thehost
is either a host name to be resolved by DNS, an IPv4 address, or an IPv6 address. IPv6 addresses must be enclosed in square brackets. If a host name resolves via DNS to multiple addresses, Elasticsearch uses all of them. DNS lookups are subject to JVM DNS caching. If theport
is not given then it is determined by checking the following settings in order:-
transport.profiles.default.port
-
transport.port
If neither of these is set then the default port is
9300
. The default value fordiscovery.seed_hosts
is["127.0.0.1", "[::1]"]
. Seediscovery.seed_hosts
.This setting was previously known as
discovery.zen.ping.unicast.hosts
. Its old name is deprecated but continues to work in order to preserve backwards compatibility. Support for the old name will be removed in a future version. -
-
discovery.seed_providers
-
(Static)
Specifies which types of seed hosts provider to
use to obtain the addresses of the seed nodes used to start the discovery
process. By default, it is the
settings-based seed hosts provider which
obtains the seed node addresses from the
discovery.seed_hosts
setting. This setting was previously known asdiscovery.zen.hosts_provider
. Its old name is deprecated but continues to work in order to preserve backwards compatibility. Support for the old name will be removed in a future version. -
discovery.type
-
(Static)
Specifies whether Elasticsearch should form a multiple-node cluster. By default, Elasticsearch
discovers other nodes when forming a cluster and allows other nodes to join
the cluster later. If
discovery.type
is set tosingle-node
, Elasticsearch forms a single-node cluster and suppresses the timeout set bycluster.publish.timeout
. For more information about when you might use this setting, see Single-node discovery. -
cluster.initial_master_nodes
-
(Static)
Sets the initial set of master-eligible nodes in a brand-new cluster. By default
this list is empty, meaning that this node expects to join a cluster that has
already been bootstrapped. See
cluster.initial_master_nodes
.
Expert settings
editDiscovery and cluster formation are also affected by the following expert-level settings, although it is not recommended to change any of these from their default values.
If you adjust these settings then your cluster may not form correctly or may become unstable or intolerant of certain failures.
-
discovery.cluster_formation_warning_timeout
-
(Static)
Sets how long a node will try to form a cluster before logging a warning that
the cluster did not form. Defaults to
10s
. If a cluster has not formed afterdiscovery.cluster_formation_warning_timeout
has elapsed then the node will log a warning message that starts with the phrasemaster not discovered
which describes the current state of the discovery process. -
discovery.find_peers_interval
-
(Static)
Sets how long a node will wait before attempting another discovery round.
Defaults to
1s
. -
discovery.probe.connect_timeout
-
(Static)
Sets how long to wait when attempting to connect to each address. Defaults to
3s
. -
discovery.probe.handshake_timeout
-
(Static)
Sets how long to wait when attempting to identify the remote node via a
handshake. Defaults to
1s
. -
discovery.request_peers_timeout
-
(Static)
Sets how long a node will wait after asking its peers again before considering
the request to have failed. Defaults to
3s
. -
discovery.seed_resolver.max_concurrent_resolvers
-
(Static)
Specifies how many concurrent DNS lookups to perform when resolving the
addresses of seed nodes. Defaults to
10
. This setting was previously known asdiscovery.zen.ping.unicast.concurrent_connects
. Its old name is deprecated but continues to work in order to preserve backwards compatibility. Support for the old name will be removed in a future version. -
discovery.seed_resolver.timeout
-
(Static)
Specifies how long to wait for each DNS lookup performed when resolving the
addresses of seed nodes. Defaults to
5s
. This setting was previously known asdiscovery.zen.ping.unicast.hosts.resolve_timeout
. Its old name is deprecated but continues to work in order to preserve backwards compatibility. Support for the old name will be removed in a future version. -
cluster.auto_shrink_voting_configuration
-
(Dynamic)
Controls whether the voting configuration sheds
departed nodes automatically, as long as it still contains at least 3 nodes. The
default value is
true
. If set tofalse
, the voting configuration never shrinks automatically and you must remove departed nodes manually with the voting configuration exclusions API. -
cluster.election.back_off_time
-
(Static)
Sets the amount to increase the upper bound on the wait before an election on
each election failure. Note that this is linear backoff. This defaults to
100ms
. Changing this setting from the default may cause your cluster to fail to elect a master node. -
cluster.election.duration
-
(Static)
Sets how long each election is allowed to take before a node considers it to
have failed and schedules a retry. This defaults to
500ms
. Changing this setting from the default may cause your cluster to fail to elect a master node. -
cluster.election.initial_timeout
-
(Static)
Sets the upper bound on how long a node will wait initially, or after the
elected master fails, before attempting its first election. This defaults to
100ms
. Changing this setting from the default may cause your cluster to fail to elect a master node. -
cluster.election.max_timeout
-
(Static)
Sets the maximum upper bound on how long a node will wait before attempting an
first election, so that an network partition that lasts for a long time does not
result in excessively sparse elections. This defaults to
10s
. Changing this setting from the default may cause your cluster to fail to elect a master node. -
cluster.fault_detection.follower_check.interval
-
(Static)
Sets how long the elected master waits between follower checks to each other
node in the cluster. Defaults to
1s
. Changing this setting from the default may cause your cluster to become unstable. -
cluster.fault_detection.follower_check.timeout
-
(Static)
Sets how long the elected master waits for a response to a follower check before
considering it to have failed. Defaults to
10s
. Changing this setting from the default may cause your cluster to become unstable. -
cluster.fault_detection.follower_check.retry_count
-
(Static)
Sets how many consecutive follower check failures must occur to each node before
the elected master considers that node to be faulty and removes it from the
cluster. Defaults to
3
. Changing this setting from the default may cause your cluster to become unstable. -
cluster.fault_detection.leader_check.interval
-
(Static)
Sets how long each node waits between checks of the elected master. Defaults to
1s
. Changing this setting from the default may cause your cluster to become unstable. -
cluster.fault_detection.leader_check.timeout
-
(Static)
Sets how long each node waits for a response to a leader check from the elected
master before considering it to have failed. Defaults to
10s
. Changing this setting from the default may cause your cluster to become unstable. -
cluster.fault_detection.leader_check.retry_count
-
(Static)
Sets how many consecutive leader check failures must occur before a node
considers the elected master to be faulty and attempts to find or elect a new
master. Defaults to
3
. Changing this setting from the default may cause your cluster to become unstable. -
cluster.follower_lag.timeout
-
(Static)
Sets how long the master node waits to receive acknowledgements for cluster
state updates from lagging nodes. The default value is
90s
. If a node does not successfully apply the cluster state update within this period of time, it is considered to have failed and is removed from the cluster. See Publishing the cluster state. -
cluster.join.timeout
-
(Static)
[7.10]
Deprecated in 7.10. Has no effect in 7.x clusters
Sets how long a node will
wait after sending a request to join a version 6.8 master before it
considers the request to have failed and retries. Defaults to
60s
. -
cluster.max_voting_config_exclusions
-
(Dynamic)
Sets a limit on the number of voting configuration exclusions at any one time.
The default value is
10
. See Adding and removing nodes. -
cluster.publish.info_timeout
-
(Static)
Sets how long the master node waits for each cluster state update to be
completely published to all nodes before logging a message indicating that some
nodes are responding slowly. The default value is
10s
. -
cluster.publish.timeout
-
(Static)
Sets how long the master node waits for each cluster state update to be
completely published to all nodes, unless
discovery.type
is set tosingle-node
. The default value is30s
. See Publishing the cluster state.
-
cluster.no_master_block
-
(Dynamic) Specifies which operations are rejected when there is no active master in a cluster. This setting has three valid values:
-
all
- All operations on the node (both read and write operations) are rejected. This also applies for API cluster state read or write operations, like the get index settings, update mapping, and cluster state API.
-
write
- (default) Write operations are rejected. Read operations succeed, based on the last known cluster configuration. This situation may result in partial reads of stale data as this node may be isolated from the rest of the cluster.
-
metadata_write
- Only metadata write operations (e.g. mapping updates, routing table changes) are rejected but regular indexing operations continue to work. Read and write operations succeed, based on the last known cluster configuration. This situation may result in partial reads of stale data as this node may be isolated from the rest of the cluster.
-
The
cluster.no_master_block
setting doesn’t apply to nodes-based APIs (for example, cluster stats, node info, and node stats APIs). Requests to these APIs are not be blocked and can run on any available node. - For the cluster to be fully operational, it must have an active master.
This setting replaces the
discovery.zen.no_master_block
setting in earlier versions. Thediscovery.zen.no_master_block
setting is ignored. -
-
monitor.fs.health.enabled
-
(Dynamic)
If
true
, the node runs periodic filesystem health checks. Defaults totrue
. -
monitor.fs.health.refresh_interval
-
(Static)
Interval between successive
filesystem health checks. Defaults
to
2m
. -
monitor.fs.health.slow_path_logging_threshold
-
(Dynamic)
If a filesystem health checks
takes longer than this threshold then Elasticsearch logs a warning. Defaults to
5s
.