pools.zeek

Cluster

Defines an interface for managing pools of cluster nodes. Pools are a useful way to distribute work or data among nodes within a cluster.

Namespace:: Cluster
Imports:: base/frameworks/cluster/main.zeek, base/utils/hash_hrw.zeek

Summary

State Variables

`Cluster::logger_pool`: `Cluster::Pool`	A pool containing all the logger nodes of a cluster.
`Cluster::logger_pool_spec`: `Cluster::PoolSpec` `&redef`	The specification for `Cluster::logger_pool`.
`Cluster::proxy_pool`: `Cluster::Pool`	A pool containing all the proxy nodes of a cluster.
`Cluster::proxy_pool_spec`: `Cluster::PoolSpec` `&redef`	The specification for `Cluster::proxy_pool`.
`Cluster::worker_pool`: `Cluster::Pool`	A pool containing all the worker nodes of a cluster.
`Cluster::worker_pool_spec`: `Cluster::PoolSpec` `&redef`	The specification for `Cluster::worker_pool`.

Types

`Cluster::PoolNode`: `record`	Store state of a cluster within the context of a work pool.
`Cluster::PoolNodeTable`: `table`
`Cluster::PoolSpec`: `record`	A pool specification.
`Cluster::RoundRobinTable`: `table`

Functions

`Cluster::hrw_topic`: `function`	Retrieve the topic associated with the node mapped via Rendezvous hash of an arbitrary key.
`Cluster::register_pool`: `function`	Registers and initializes a pool.
`Cluster::rr_log_topic`: `function`	Distributes log message topics among logger nodes via round-robin.
`Cluster::rr_topic`: `function`	Retrieve the topic associated with the node in a round-robin fashion.

Detailed Interface

State Variables

Cluster::logger_pool 

Type:

Cluster::Pool

Default:

{
   spec=[topic=<uninitialized>, node_type=<uninitialized>, max_nodes=<uninitialized>, exclusive=F]
   nodes={

   }
   node_list=[]
   hrw_pool=[sites={

   }]
   rr_key_seq={

   }
   alive_count=0
}

A pool containing all the logger nodes of a cluster. The pool’s node membership/availability is automatically maintained by the cluster framework.

Cluster::logger_pool_spec 

Type:

Cluster::PoolSpec

Attributes:

&redef

Default:

{
   topic="zeek/cluster/pool/logger"
   node_type=Cluster::LOGGER
   max_nodes=<uninitialized>
   exclusive=F
}

Redefinition:

from policy/frameworks/cluster/backend/zeromq/main.zeek

=:

Cluster::PoolSpec($topic=zeek.cluster.pool.logger, $node_type=Cluster::LOGGER)

The specification for Cluster::logger_pool.

Cluster::proxy_pool 

Type:

Cluster::Pool

Default:

{
   spec=[topic=<uninitialized>, node_type=<uninitialized>, max_nodes=<uninitialized>, exclusive=F]
   nodes={

   }
   node_list=[]
   hrw_pool=[sites={

   }]
   rr_key_seq={

   }
   alive_count=0
}

A pool containing all the proxy nodes of a cluster. The pool’s node membership/availability is automatically maintained by the cluster framework.

Cluster::proxy_pool_spec 

Type:

Cluster::PoolSpec

Attributes:

&redef

Default:

{
   topic="zeek/cluster/pool/proxy"
   node_type=Cluster::PROXY
   max_nodes=<uninitialized>
   exclusive=F
}

Redefinition:

from policy/frameworks/cluster/backend/zeromq/main.zeek

=:

Cluster::PoolSpec($topic=zeek.cluster.pool.proxy, $node_type=Cluster::PROXY)

The specification for Cluster::proxy_pool.

Cluster::worker_pool 

Type:

Cluster::Pool

Default:

{
   spec=[topic=<uninitialized>, node_type=<uninitialized>, max_nodes=<uninitialized>, exclusive=F]
   nodes={

   }
   node_list=[]
   hrw_pool=[sites={

   }]
   rr_key_seq={

   }
   alive_count=0
}

A pool containing all the worker nodes of a cluster. The pool’s node membership/availability is automatically maintained by the cluster framework.

Cluster::worker_pool_spec 

Type:

Cluster::PoolSpec

Attributes:

&redef

Default:

{
   topic="zeek/cluster/pool/worker"
   node_type=Cluster::WORKER
   max_nodes=<uninitialized>
   exclusive=F
}

Redefinition:

from policy/frameworks/cluster/backend/zeromq/main.zeek

=:

Cluster::PoolSpec($topic=zeek.cluster.pool.worker, $node_type=Cluster::WORKER)

The specification for Cluster::worker_pool.

Types

Cluster::PoolNode 

Type:

record

Fields:

name: string: The node name (e.g. “manager”).

alias: string: An alias of name used to prevent hashing collisions when creating site_id.

site_id: count: A 32-bit unique identifier for the pool node, derived from name/alias.

alive: bool &default = F &optional: Whether the node is currently alive and can receive work.

topic: string: The pre-computed result from Cluster::node_topic

Store state of a cluster within the context of a work pool.

Cluster::PoolNodeTable 

Type:: table [string] of Cluster::PoolNode

Cluster::PoolSpec 

Type:

record

Fields:

topic: string: A topic string that can be used to reach all nodes within a pool.

node_type: Cluster::NodeType: The type of nodes that are contained within the pool.

max_nodes: count &optional: The maximum number of nodes that may belong to the pool. If not set, then all available nodes will be added to the pool, else the cluster framework will automatically limit the pool membership according to the threshold.

exclusive: bool &default = F &optional: Whether the pool requires exclusive access to nodes. If true, then max_nodes nodes will not be assigned to any other pool. When using this flag, max_nodes must also be set.

A pool specification.

Cluster::RoundRobinTable 

Type:: table [string] of int

Functions

Cluster::hrw_topic 

Type:: function (pool: Cluster::Pool, key: any) : string

Retrieve the topic associated with the node mapped via Rendezvous hash of an arbitrary key.

Parameters:

pool – the pool of nodes to consider.
key – data used for input to the hashing function that will uniformly distribute keys among available nodes.

Returns:

a topic string associated with a cluster node that is alive or an empty string if nothing is alive.

Cluster::register_pool 

Type:: function (spec: Cluster::PoolSpec) : Cluster::Pool

Registers and initializes a pool.

Cluster::rr_log_topic 

Type:: function (id: Log::ID, path: string) : string

Distributes log message topics among logger nodes via round-robin. This will be automatically assigned to Broker::log_topic if Cluster::enable_round_robin_logging is enabled. If no logger nodes are active, then this will return the value of Broker::default_log_topic.

Cluster::rr_topic 

Type:: function (pool: Cluster::Pool, key: string &default = "" &optional) : string

Retrieve the topic associated with the node in a round-robin fashion.

Parameters:

pool – the pool of nodes to consider.
key – an arbitrary string to identify the purpose for which you’re requesting the topic. e.g. consider using a name-spaced key like “Intel::cluster_rr_key” if you need to guarantee that a group of messages get distributed in a well-defined pattern without other messages being interleaved within the round-robin. Usually sharing the default key is fine for load-balancing purposes.

Returns:

a topic string associated with a cluster node that is alive, or an empty string if nothing is alive.