Initialize and Connect to H2O

Source: R/connection.R

Attempts to start and/or connect to and H2O instance.

h2o.init(
  ip = "localhost",
  port = 54321,
  name = NA_character_,
  startH2O = TRUE,
  forceDL = FALSE,
  enable_assertions = TRUE,
  license = NULL,
  nthreads = -1,
  max_mem_size = NULL,
  min_mem_size = NULL,
  ice_root = tempdir(),
  log_dir = NA_character_,
  log_level = NA_character_,
  strict_version_check = TRUE,
  proxy = NA_character_,
  https = FALSE,
  cacert = NA_character_,
  insecure = FALSE,
  username = NA_character_,
  password = NA_character_,
  use_spnego = FALSE,
  cookies = NA_character_,
  context_path = NA_character_,
  ignore_config = FALSE,
  extra_classpath = NULL,
  jvm_custom_args = NULL,
  bind_to_localhost = TRUE
)

Arguments

ip

Object of class character representing the IP address of the server where H2O is running.
port

Object of class numeric representing the port number of the H2O server.
name

(Optional) A character string representing the H2O cluster name.
startH2O

(Optional) A logical value indicating whether to try to start H2O from R if no connection with H2O is detected. This is only possible if ip = "localhost" or ip = "127.0.0.1". If an existing connection is detected, R does not start H2O.
forceDL

(Optional) A logical value indicating whether to force download of the H2O executable. Defaults to FALSE, so the executable will only be downloaded if it does not already exist in the h2o R library resources directory h2o/java/h2o.jar. This value is only used when R starts H2O.
enable_assertions

(Optional) A logical value indicating whether H2O should be launched with assertions enabled. Used mainly for error checking and debugging purposes. This value is only used when R starts H2O.
license

(Optional) A character string value specifying the full path of the license file. This value is only used when R starts H2O.
nthreads

(Optional) Number of threads in the thread pool. This relates very closely to the number of CPUs used. -1 means use all CPUs on the host (Default). A positive integer specifies the number of CPUs directly. This value is only used when R starts H2O.
max_mem_size

(Optional) A character string specifying the maximum size, in bytes, of the memory allocation pool to H2O. This value must a multiple of 1024 greater than 2MB. Append the letter m or M to indicate megabytes, or g or G to indicate gigabytes. This value is only used when R starts H2O. If max_mem_size is not defined, then the amount of memory that H2O allocates will be determined by the default memory of Java Virtual Machine. This amount is dependent on the Java version, but it will generally be 25 percent of the machine's physical memory.
min_mem_size

(Optional) A character string specifying the minimum size, in bytes, of the memory allocation pool to H2O. This value must a multiple of 1024 greater than 2MB. Append the letter m or M to indicate megabytes, or g or G to indicate gigabytes. This value is only used when R starts H2O.
ice_root

(Optional) A directory to handle object spillage. The defaul varies by OS.
log_dir

(Optional) A directory where H2O server logs are stored. The default varies by OS.
log_level

(Optional) The level of logging of H2O server. The default is INFO.
strict_version_check

(Optional) Setting this to FALSE is unsupported and should only be done when advised by technical support.
proxy

(Optional) A character string specifying the proxy path.
https

(Optional) Set this to TRUE to use https instead of http.
cacert

(Optional) Path to a CA bundle file with root and intermediate certificates of trusted CAs.
insecure

(Optional) Set this to TRUE to disable SSL certificate checking.
username

(Optional) Username to login with.
password

(Optional) Password to login with.
use_spnego

(Optional) Set this to TRUE to enable SPNEGO authentication.
cookies

(Optional) Vector(or list) of cookies to add to request.
context_path

(Optional) The last part of connection URL: http://<ip>:<port>/<context_path>
ignore_config

(Optional) A logical value indicating whether a search for a .h2oconfig file should be conducted or not. Default value is FALSE.
extra_classpath

(Optional) A vector of paths to libraries to be added to the Java classpath when H2O is started from R.
jvm_custom_args

(Optional) A character list of custom arguments for the JVM where new H2O instance is going to run, if started. Ignored when connecting to an existing instance.
bind_to_localhost

(Optional) A logical flag indicating whether access to the H2O instance should be restricted to the local machine (default) or if it can be reached from other computers on the network. Only applicable when H2O is started from R.

Value

this method will load it and return a H2OConnection object containing the IP address and port number of the H2O server.

Details

By default, this method first checks if an H2O instance is connectible. If it cannot connect and start = TRUE with ip = "localhost", it will attempt to start and instance of H2O at localhost:54321. If an open ip and port of your choice are passed in, then this method will attempt to start an H2O instance at that specified ip port.

When initializing H2O locally, this method searches for h2o.jar in the R library resources (system.file("java", "h2o.jar", package = "h2o")), and if the file does not exist, it will automatically attempt to download the correct version from Amazon S3. The user must have Internet access for this process to be successful.

Once connected, the method checks to see if the local H2O R package version matches the version of H2O running on the server. If there is a mismatch and the user indicates she wishes to upgrade, it will remove the local H2O R package and download/install the H2O R package from the server.

Note

Users may wish to manually upgrade their package (rather than waiting until being prompted), which requires that they fully uninstall and reinstall the H2O package, and the H2O client package. You must unload packages running in the environment before upgrading. It's recommended that users restart R or R studio after upgrading

See also

H2O R package documentation for more details. h2o.shutdown for shutting down from R.

Examples

if (FALSE) {
# Try to connect to a local H2O instance that is already running.
# If not found, start a local H2O instance from R with the default settings.
h2o.init()

# Try to connect to a local H2O instance.
# If not found, raise an error.
h2o.init(startH2O = FALSE)

# Try to connect to a local H2O instance that is already running.
# If not found, start a local H2O instance from R with 5 gigabytes of memory.
h2o.init(max_mem_size = "5g")

# Try to connect to a local H2O instance that is already running.
# If not found, start a local H2O instance from R that uses 5 gigabytes of memory.
h2o.init(max_mem_size = "5g")
}