ArangoDB Server Clusters Options

Agency endpoint

List of Agency endpoints:

--cluster.agency-endpoint <endpoint>

An Agency endpoint the server can connect to. The option can be specified multiple times, so the server can use a cluster of Agency servers. Endpoints have the following pattern:

  • tcp://ipv4-address:port - TCP/IP endpoint, using IPv4
  • tcp://[ipv6-address]:port - TCP/IP endpoint, using IPv6
  • ssl://ipv4-address:port - TCP/IP endpoint, using IPv4, SSL encryption
  • ssl://[ipv6-address]:port - TCP/IP endpoint, using IPv6, SSL encryption

At least one endpoint must be specified or ArangoDB will refuse to start. It is recommended to specify at least two endpoints so ArangoDB has an alternative endpoint if one of them becomes unavailable.

Examples

--cluster.agency-endpoint tcp://192.168.1.1:4001 --cluster.agency-endpoint tcp://192.168.1.2:4002 ...

My address

This server’s address / endpoint:

--cluster.my-address <endpoint>

The server’s endpoint for cluster-internal communication. If specified, it must have the following pattern:

  • tcp://ipv4-address:port - TCP/IP endpoint, using IPv4
  • tcp://[ipv6-address]:port - TCP/IP endpoint, using IPv6
  • ssl://ipv4-address:port - TCP/IP endpoint, using IPv4, SSL encryption
  • ssl://[ipv6-address]:port - TCP/IP endpoint, using IPv6, SSL encryption

If no endpoint is specified, the server will look up its internal endpoint address in the Agency. If no endpoint can be found in the Agency for the server’s id, ArangoDB will refuse to start.

Examples

Listen only on interface with address 192.168.1.1:

--cluster.my-address tcp://192.168.1.1:8530

Listen on all ipv4 and ipv6 addresses, which are configured on port 8530:

--cluster.my-address ssl://[::]:8530

My advertised endpoint

This server’s advertised endpoint (e.g. external IP address or load balancer, optional):

--cluster.my-advertised-endpoint <endpoint>

This servers’s endpoint for external communication. If specified, it must have the following pattern:

  • tcp://ipv4-address:port - TCP/IP endpoint, using IPv4
  • tcp://[ipv6-address]:port - TCP/IP endpoint, using IPv6
  • ssl://ipv4-address:port - TCP/IP endpoint, using IPv4, SSL encryption
  • ssl://[ipv6-address]:port - TCP/IP endpoint, using IPv6, SSL encryption

If no advertised endpoint is specified, no external endpoint will be advertised.

Examples

If an external interface is available to this server, it can be specified to communicate with external software / drivers:

--cluster.my-advertised-endpoint tcp://some.public.place:8530

All specifications of endpoints apply.

My role

This server’s role:

--cluster.my-role <dbserver|coordinator>

The server’s role. Is this instance a DB-Server (backend data server) or a Coordinator (frontend server for external and application access).

Require existing ID

Require an existing server id:

--cluster.require-persisted-id <bool>

If set to true, then the instance will only start if a UUID file is found in the database on startup. Setting this option will make sure the instance is started using an already existing database directory from a previous start, and not a new one. For the first start, the UUID file must either be created manually in the database directory, or the option must be set to false for the initial startup and only turned on for restarts.

API JWT policy

Introduced in: v3.8.0

Control the access permissions for the /_admin/cluster REST API endpoints:

--cluster.api-jwt-policy <string>

This security option controls whether extra access permissions for the /_admin/cluster REST API endpoints should be enabled.

The possible values for the option are:

  • jwt-all: requires a valid JWT for all accesses to /_admin/cluster and its sub-routes. If this configuration is used, the CLUSTER and NODES sections of the web interface will be disabled, as they are relying on the ability to read data from several cluster APIs.
  • jwt-write: requires a valid JWT for write accesses (all HTTP methods except HTTP GET) to /_admin/cluster. This setting can be used to allow privileged users to read data from the cluster APIs, but not to do any modifications. Modifications (carried out by write accesses) are then only possible by requests with a valid JWT. All existing permission checks for the cluster API routes are still in effect with this setting, meaning that read operations without a valid JWT may still require dedicated other permissions (as in v3.7).
  • jwt-compat: no additional access checks are in place for the cluster API. However, all existing permissions checks for the cluster API routes are still in effect with this setting, meaning that all operations may still require dedicated other permissions (as in v3.7).

The default value for the option is jwt-compat, which means that this option will not cause any extra JWT checks compared to v3.7.

Upgrade

Introduced in: v3.6.0

Toggle cluster upgrade mode on a Coordinator:

--cluster.upgrade <string>

The following values can be used for the options:

  • auto: perform a cluster upgrade and shut down afterwards if the startup option --database.auto-upgrade is set to true. Otherwise, do not perform an upgrade.
  • disable: never perform a cluster upgrade, regardless of the value of --database.auto-upgrade.
  • force: always perform a cluster upgrade and shut down, regardless of the value of --database.auto-upgrade.
  • online: always perform a cluster upgrade but don’t shut down afterwards

The default value is auto. The option only affects Coordinators. It does not have any affect on single servers, Agents or DB-Servers.

More advanced options

When multiple Coordinators are used, the following options should have identical values on all Coordinators.

Maximum number of move shards

Introduced in: v3.9.0

--cluster.max-number-of-move-shards <integer>

Limits the maximum number of move shards operations that can be made when the Rebalance Shards button is clicked in the Web UI. For backwards compatibility purposes, the default value is 10. If the value is 0, the tab containing this button will be inactive and the button cannot be clicked. For more information, refer to Rebalance Shards.

Maximum number of shards

Introduced in: v3.5.1

--cluster.max-number-of-shards <integer>

Maximum number of shards than can be configured when creating new collections. The default value is 1000.

When changing the value of this setting and restarting servers, no changes will be applied to existing collections that would violate the new setting.

The option only affects Coordinators. It does not have any affect on single servers, Agents or DB-Servers.

Force OneShard

Introduced in: v3.6.0

--cluster.force-one-shard <bool>

This option is only available in the Enterprise Edition, including ArangoDB Oasis.

When set to true, forces the cluster into creating all future collections with only a single shard and using the same DB-Server as these collections’ shards leader. All collections created this way will be eligible for specific AQL query optimizations that can improve query performance and provide advanced transactional guarantees.

The option only affects Coordinators. It does not have any affect on single servers, Agents or DB-Servers.

Synchronous replication minimum timeout

Introduced in: v3.4.8, v3.5.1

--cluster.synchronous-replication-timeout-minimum <double>

This option should generally remain untouched and only changed with great care.

The minimum timeout in seconds for the internal synchronous replication mechanism between DB-Servers. If replication requests are slow, but the servers are otherwise healthy, timeouts can cause followers to be dropped unnecessarily, resulting in costly resync operations. Increasing this value may help avoid such resyncs. Conversely, decreasing it may cause more resyncs, while lowering the latency of individual write operations. Default at 30.0 seconds.

Synchronous replication timeout scaling

--cluster.synchronous-replication-timeout-factor <double>

This option should generally remain untouched and only changed with great care.

Stretch or clinch timeouts for internal synchronous replication mechanism between DB-Servers. All such timeouts are affected by this change. Default at 1.0.

System replication factor

--cluster.system-replication-factor <integer>

Change default replication factor for system collections. Default at 2.

The option only affects Coordinators. It does not have any affect on single servers, Agents or DB-Servers.

Minimum replication factor

--cluster.min-replication-factor <integer>

Introduced in: v3.5.1

Minimum replication factor that needs to be used when creating new collections. The default value is 1. When changing the value of this setting and restarting servers, no changes will be applied to existing collections that would violate the new setting.

The option only affects Coordinators. It does not have any affect on single servers, Agents or DB-Servers.

Maximum replication factor

Introduced in: v3.5.1

--cluster.max-replication-factor <integer>

Maximum replication factor that can be used when creating new collections. The default value is 10. When changing the value of this setting and restarting servers, no changes will be applied to existing collections that would violate the new setting.

The option only affects Coordinators. It does not have any affect on single servers, Agents or DB-Servers.

Default replication factor

--cluster.default-replication-factor <integer>

Default replication factor to be used implicit for new collections when no replication factor is set.

If this value is not set, it will default to the value of the option --cluster.min-replication-factor. If set, the value must be between the values of --cluster.min-replication-factor and --cluster.max-replication-factor. Note that the replication factor can still be adjusted per collection. This value is only the default value used for new collections when no replication factor is specified when creating a collection.

The option only affects Coordinators. It does not have any affect on single servers, Agents or DB-Servers.

Write concern

Introduced in: v3.6.0

--cluster.write-concern <integer>

Sets the global default write concern. Used by databases as default, which in turn is used by collections as default.

Also see:

❮  Backup

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