flux-config-tbon(5)

DESCRIPTION

The tbon table may be used to tune the configuration of the Flux tree-based overlay network (TBON).

It may contain the following keys:

KEYS

topo

(optional) A URI that selects a specific tree topology. The default value is kary:32 when bootstrapping from PMI, and custom when bootstrapping from configuration, as described in flux-config-bootstrap(5). The configured value may be overridden by setting the tbon.topo broker attribute.

torpid_min

(optional) The amount of time (in RFC 23 Flux Standard Duration format) that a broker will allow the connection to its TBON parent to remain idle before sending a control message to create activity. The default value of 5s should be reasonable in most circumstances. This configured value may be overridden by setting the tbon.torpid_min broker attribute.

torpid_max

(optional) The amount of time (in RFC 23 Flux Standard Duration format) that a broker will wait for an idle TBON child connection to send messages before declaring it torpid (unresponsive). A value of 0 disables torpid node checking. New work is not scheduled on a node while torpid, but a job running on a node when it becomes torpid is allowed to complete. This configured value may be overridden by setting the tbon.torpid_max broker attribute.

tcp_user_timeout

(optional) The amount of time (in RFC 23 Flux Standard Duration format) that a broker waits for a TBON child connection to acknowledge transmitted TCP data before forcibly closing the connection. A value of 0 means use the system default. This value affects how Flux responds to an abruptly turned off node. The configured value may be overridden by setting the tbon.tcp_user_timeout broker attribute. See also: tcp(7), TCP_USER_TIMEOUT socket option. Default: 20s.

connect_timeout

(optional) The amount of time (in RFC 23 Flux Standard Duration format) that a broker waits for a connect(1) attempt to its TBON parent to succeed before before retrying. A value of 0 means use the system default. The configured value may be overridden by setting the tbon.connect_timeout broker attribute. Default: 30s.

zmqdebug

(optional) Integer value indicating whether ZeroMQ socket debug logging should be enabled: 0=disabled, 1=enabled. Default: 0. This configured value may be overridden by setting the tbon.zmqdebug broker attribute.

zmq_io_threads

(optional) Integer value to set the number of I/O threads libzmq will start on the leader node. The default is 1. This configured value may be overridden by setting the tbon.zmq_io_threads broker attribute.

child_rcvhwm

(optional) Integer value that limits the number of messages stored locally on behalf of each downstream TBON peer. When the limit is reached, messages are queued on the peer instead. Setting this reduces memory usage for nodes with a large number of downstream peers, at the expense of message latency. The value should be 0 (unlimited) or >= 2. The default is 0. This configured value may be overridden by setting the tbon.child_rcvhwm broker attribute.

interface-hint

When the broker's bind address is not explicitly configured via flux-config-bootstrap(5), it is chosen dynamically, influenced by one of the following hints:

default-route: The address associated with the default route (the default hint).
hostname: The address associated with the system hostname.
interface: The address associated with the named network interface, e.g. enp4s0
network: The address associated with the first interface that matches the network address in CIDR form, e.g. 10.0.2.0/24. NOTE: IPv6 network addresses are not supported at this time.

This configured value may be overridden by setting the tbon.interface-hint broker attribute on the command line. It is inherited by sub-instances spawned for batch jobs and allocations. Refer to flux-broker-attributes(7) for more information.

EXAMPLE

[tbon]
torpid_min = "10s"
torpid_max = "1m"

tcp_user_timeout = "2m"

RESOURCES

Flux: http://flux-framework.org

Flux RFC: https://flux-framework.readthedocs.io/projects/flux-rfc

Issue Tracker: https://github.com/flux-framework/flux-core/issues

FLUX RFC

23/Flux Standard Duration