remote: Create a remote future whose value will be resolved asynchronously in a remote process

Description

A remote future is a future that uses remote cluster evaluation, which means that its value is computed and resolved remotely in another process.

Usage

remote(
  ...,
  workers = NULL,
  revtunnel = TRUE,
  myip = NULL,
  persistent = TRUE,
  homogeneous = TRUE,
  envir = parent.frame()
)

Value

A ClusterFuture.

Arguments

...: Additional named elements passed to Future().
workers: A cluster object, a character vector of host names, a positive numeric scalar, or a function. If a character vector or a numeric scalar, a cluster object is created using makeClusterPSOCK(workers). If a function, it is called without arguments when the future is created and its value is used to configure the workers. The function should return any of the above types.
revtunnel: If TRUE, reverse SSH tunneling is used for the PSOCK cluster nodes to connect back to the master R process. This avoids the hassle of firewalls, port forwarding and having to know the internal / public IP address of the master R session.
myip: The external IP address of this machine. If NULL, then it is inferred using an online service (default).
persistent: If FALSE, the evaluation environment is cleared from objects prior to the evaluation of the future.
homogeneous: If TRUE, all cluster nodes is assumed to use the same path to Rscript as the main R session. If FALSE, the it is assumed to be on the PATH for each node. If NULL, then parallelly::makeClusterPSOCK() will decide on TRUE or FALSE depending on workers.
envir: The environment from where global objects should be identified.

'remote' versus 'cluster'

The remote plan is a very similar to the cluster plan, but provides more convenient default argument values when connecting to remote machines. #' Specifically, remote uses persistent = TRUE by default, and it sets homogeneous, revtunnel, and myip "wisely" depending on the value of workers. ' See below for example on how remote and cluster are related.

Details

This function is not meant to be called directly. Instead, the typical usages are:

# Evaluate futures on remote machine 'server.example.org', and
# any nested ones sequentially (default) on that remote machine
plan(remote, workers = "server.example.org")
# Evaluate futures on remote machine 'server.example.org', and
# nested ones in parallel on that remote machine
plan(list(
   tweak(remote, workers = "server.example.org"),
   multisession
))
# Evaluate futures on remote machine 'server.example.org', and
# nested ones in parallel on the remote machines n1, n2, and n3.
plan(list(
  tweak(remote, workers = "server.example.org"),
  tweak(cluster, workers = c("n1", "n2", "n3"))
))