Sparkling Water Configuration Properties

The following configuration properties can be passed to Spark to configure Sparking Water.

Configuration properties independent of selected backend

Property name

Default value

H2OConf setter (* getter)

Description

Generic parameters

spark.ext.h2o.backend.cluster.mode

internal

setInternalClusterMode()

setExternalClusterMode()

This option can be set either to internal or external. When set to external, H2O Context is created by connecting to existing H2O cluster, otherwise H2O cluster located inside Spark is created. That means that each Spark executor will have one H2O instance running in it. The internal mode is not recommended for big clusters and clusters where Spark executors are not stable.

spark.ext.h2o.cloud.name

Generated unique name

setCloudName(String)

Name of H2O cluster.

spark.ext.h2o.nthreads

-1

setNthreads(Integer)

Limit for number of threads used by H2O, default -1 means: Use value of spark.executor.cores in case this property is set. Otherwise use H2O’s default value Runtime.getRuntime().availableProcessors().

spark.ext.h2o.repl.enabled

true

setReplEnabled()

setReplDisabled()

Decides whether H2O REPL is initiated or not.

spark.ext.scala.int.default.num

1

setDefaultNumReplSessions(Integer)

Number of parallel REPL sessions started at the start of Sparkling Water

spark.ext.h2o.topology.change.listener.enabled

true

setClusterTopologyListenerEnabled()

setClusterTopologyListenerDisabled()

Decides whether listener which kills H2O cluster on the change of the underlying cluster’s topology is enabled or not. This configuration has effect only in non-local mode.

spark.ext.h2o.spark.version.check.enabled

true

setSparkVersionCheckEnabled()

setSparkVersionCheckDisabled()

Enables check if run-time Spark version matches build time Spark version.

spark.ext.h2o.fail.on.unsupported.spark.param

true

setFailOnUnsupportedSparkParamEnabled()

setFailOnUnsupportedSparkParamDisabled()

If unsupported Spark parameter is detected, then application is forced to shutdown.

spark.ext.h2o.jks

None

setJks(String)

Path to Java KeyStore file.

spark.ext.h2o.jks.pass

None

setJksPass(String)

Password for Java KeyStore file.

spark.ext.h2o.jks.alias

None

setJksAlias(String)

Alias to certificate in keystore to secure H2O Flow.

spark.ext.h2o.hash.login

false

setHashLoginEnabled()

setHashLoginDisabled()

Enable hash login.

spark.ext.h2o.ldap.login

false

setLdapLoginEnabled()

setLdapLoginDisabled()

Enable LDAP login.

spark.ext.h2o.kerberos.login

false

setKerberosLoginEnabled()

setKerberosLoginDisabled()

Enable Kerberos login.

spark.ext.h2o.login.conf

None

setLoginConf(String)

Login configuration file.

spark.ext.h2o.user.name

None

setUserName(String)

Username used for the backend H2O cluster and to authenticate the client against the backend.

spark.ext.h2o.password

None

setPassword(String)

Password used to authenticate the client against the backend.

spark.ext.h2o.internal_security_conf

None

setSslConf(String)

Path to a file containing H2O or Sparkling Water internal security configuration.

spark.ext.h2o.auto.flow.ssl

false

setAutoFlowSslEnabled()

setAutoFlowSslDisabled()

Automatically generate the required key store and password to secure H2O flow by SSL.

spark.ext.h2o.node.log.level

INFO

setH2ONodeLogLevel(String)

H2O internal log level used for H2O nodes except the client.

spark.ext.h2o.node.log.dir

{user.dir}/h2ologs/{SparkAppId}

or YARN container dir

setH2ONodeLogDir(String)

Location of H2O logs on H2O nodes except on the client.

spark.ext.h2o.backend.heartbeat.interval

10000ms

setBackendHeartbeatInterval(Integer)

Interval for getting heartbeat from the H2O backend.

spark.ext.h2o.cloud.timeout

60*1000

setCloudTimeout(Integer)

Timeout (in msec) for cluster formation.

spark.ext.h2o.node.network.mask

None

setNodeNetworkMask(String)

Subnet selector for H2O running inside Spark executors. This disables using IP reported by Spark but tries to find IP based on the specified mask.

spark.ext.h2o.stacktrace.collector.interval

-1

setStacktraceCollectorInterval(Integer)

Interval specifying how often stack traces are taken on each H2O node. -1 means that no stack traces will be taken.

spark.ext.h2o.context.path

None

setContextPath(String)

Context path to expose H2O web server.

spark.ext.h2o.flow.scala.cell.async

false

setFlowScalaCellAsyncEnabled()

setFlowScalaCellAsyncDisabled()

Decide whether the Scala cells in H2O Flow will run synchronously or Asynchronously. Default is synchronously.

spark.ext.h2o.flow.scala.cell.max.parallel

-1

setMaxParallelScalaCellJobs(Integer)

Number of max parallel Scala cell jobs The value -1 means not limited.

spark.ext.h2o.internal.port.offset

1

setInternalPortOffset(Integer)

Offset between the API(=web) port and the internal communication port on the client node; api_port + port_offset = h2o_port

spark.ext.h2o.node.port.base

54321

setNodeBasePort(Integer)

Base port used for individual H2O nodes.

spark.ext.h2o.mojo.destroy.timeout

600000

setMojoDestroyTimeout(Integer)

If a scoring MOJO instance is not used within a Spark executor JVM for a given timeout in milliseconds, it’s evicted from executor’s cache. Default timeout value is 10 minutes.

spark.ext.h2o.node.extra

None

setNodeExtraProperties(String)

A string containing extra parameters passed to H2O nodes during startup. This parameter should be configured only if H2O parameters do not have any corresponding parameters in Sparkling Water.

spark.ext.h2o.flow.extra.http.headers

None

setFlowExtraHttpHeaders(Map[String,String])

setFlowExtraHttpHeaders(String)

Extra HTTP headers that will be used in communication between the front-end and back-end part of Flow UI. The headers should be delimited by a new line. Don’t forget to escape special characters when passing the parameter from a command line.

spark.ext.h2o.internal_secure_connections

false

setInternalSecureConnectionsEnabled()

setInternalSecureConnectionsDisabled()

Enables secure communications among H2O nodes. The security is based on automatically generated keystore and truststore. This is equivalent for -internal_secure_conections option in H2O Hadoop deployments.

H2O client parameters

spark.ext.h2o.client.flow.dir

None

setFlowDir(String)

Directory where flows from H2O Flow are saved.

spark.ext.h2o.client.ip

None

setClientIp(String)

IP of H2O client node.

spark.ext.h2o.client.iced.dir

None

setClientIcedDir(String)

Location of iced directory for the driver instance.

spark.ext.h2o.client.log.level

INFO

setH2OClientLogLevel(String)

H2O internal log level used for H2O client running inside Spark driver.

spark.ext.h2o.client.log.dir

{user.dir}/h2ologs/{SparkAppId}

setH2OClientLogDir(String)

Location of H2O logs on the driver machine.

spark.ext.h2o.client.port.base

54321

setClientBasePort(Integer)

Port on which H2O client publishes its API. If already occupied, the next odd port is tried on so on.

spark.ext.h2o.client.web.port

-1

setClientWebPort(Integer)

Exact client port to access web UI. The value -1 means automatic search for a free port starting at spark.ext.h2o.port.base.

spark.ext.h2o.client.verbose

false

setClientVerboseEnabled()

setClientVerboseDisabled()

The client outputs verbose log output directly into console. Enabling the flag increases the client log level to INFO.

spark.ext.h2o.client.network.mask

None

setClientNetworkMask(String)

Subnet selector for H2O client, this disables using IP reported by Spark but tries to find IP based on the specified mask.

spark.ext.h2o.client.flow.baseurl.override

None

setClientFlowBaseurlOverride(String)

Allows to override the base URL address of Flow UI, including the scheme, which is showed to the user.

spark.ext.h2o.cluster.client.retry.timeout

60000

setClientCheckRetryTimeout(Integer)

Timeout in milliseconds specifying how often we check whether the the client is still connected.

spark.ext.h2o.client.extra

None

setClientExtraProperties(String)

A string containing extra parameters passed to H2O client during startup. This parameter should be configured only if H2O parameters do not have any corresponding parameters in Sparkling Water.

spark.ext.h2o.verify_ssl_certificates

True

setVerifySslCertificates(Boolean)

Whether certificates should be verified before using in H2O or not.


Internal backend configuration properties

Property name

Default value

H2OConf setter (* getter)

Description

Generic parameters

spark.ext.h2o.cluster.size

None

setNumH2OWorkers(Integer)

Expected number of workers of H2O cluster. Value None means automatic detection of cluster size. This number must be equal to number of Spark executors.

spark.ext.h2o.dummy.rdd.mul.factor

10

setDrddMulFactor(Integer)

Multiplication factor for dummy RDD generation. Size of dummy RDD is spark.ext.h2o.cluster.size * spark.ext.h2o.dummy.rdd.mul.factor .

spark.ext.h2o.spreadrdd.retries

10

setNumRddRetries(Integer)

Number of retries for creation of an RDD spread across all existing Spark executors.

spark.ext.h2o.default.cluster.size

20

setDefaultCloudSize(Integer)

Starting size of cluster in case that size is not explicitly configured.

spark.ext.h2o.subseq.tries

5

setSubseqTries(Integer)

Subsequent successful tries to figure out size of Spark cluster, which are producing the same number of nodes.

spark.ext.h2o.hdfs_conf

sc.hadoopConfig

setHdfsConf(String)

Either a string with the Path to a file with Hadoop HDFS configuration or the org.apache.hadoop.conf.Configuration object. Useful for HDFS credentials settings and other HDFS-related configurations.

H2O nodes parameters

spark.ext.h2o.node.iced.dir

None

setNodeIcedDir(String)

Location of iced directory for H2O nodes on the Spark executors.


External backend configuration properties

Property name

Default value

H2OConf setter (* getter)

Description

spark.ext.h2o.cloud.representative

None

setH2OCluster(String)

ip:port of arbitrary H2O node to identify external H2O cluster.

spark.ext.h2o.external.cluster.size

None

setClusterSize(Integer)

Number of H2O nodes to start in auto mode and wait for in manual mode when starting Sparkling Water in external H2O cluster mode.

spark.ext.h2o.cluster.start.timeout

120s

setClusterStartTimeout(Integer)

Timeout in seconds for starting H2O external cluster.

spark.ext.h2o.cluster.info.name

None

setClusterInfoFile(Integer)

Full path to a file which is used sd the notification file for the startup of external H2O cluster.

spark.ext.h2o.hadoop.memory

6G

setMapperXmx(String)

Amount of memory assigned to each H2O node on YARN/Hadoop.

spark.ext.h2o.external.hdfs.dir

None

setHDFSOutputDir(String)

Path to the directory on HDFS used for storing temporary files.

spark.ext.h2o.external.start.mode

manual

useAutoClusterStart()

useManualClusterStart()

If this option is set to auto then H2O external cluster is automatically started using the provided H2O driver JAR on YARN, otherwise it is expected that the cluster is started by the user manually.

spark.ext.h2o.external.h2o.driver

None

setH2ODriverPath(String)

Path to H2O driver used during auto start mode.

spark.ext.h2o.external.yarn.queue

None

setYARNQueue(String)

Yarn queue on which external H2O cluster is started.

spark.ext.h2o.external.kill.on.unhealthy

true

setKillOnUnhealthyClusterEnabled()

setKillOnUnhealthyClusterDisabled()

If true, the client will try to kill the cluster and then itself in case some nodes in the cluster report unhealthy status.

spark.ext.h2o.external.kerberos.principal

None

setKerberosPrincipal(String)

Kerberos Principal.

spark.ext.h2o.external.kerberos.keytab

None

setKerberosKeytab(String)

Kerberos Keytab.

spark.ext.h2o.external.run.as.user

None

setRunAsUser(String)

Impersonated Hadoop user.

spark.ext.h2o.external.driver.if

None

setExternalH2ODriverIf(String)

Ip address or network of mapper->driver callback interface. Default value means automatic detection.

spark.ext.h2o.external.driver.port

None

setExternalH2ODriverPort(Integer)

Port of mapper->driver callback interface. Default value means automatic detection.

spark.ext.h2o.external.driver.port.range

None

setExternalH2ODriverPortRange(String)

Range portX-portY of mapper->driver callback interface; eg: 50000-55000.

spark.ext.h2o.external.extra.memory.percent

10

setExternalExtraMemoryPercent(Integer)

This option is a percentage of spark.ext.h2o.hadoop.memory and specifies memory for internal JVM use outside of Java heap.

spark.ext.h2o.external.backend.stop.timeout

10000ms

setExternalBackendStopTimeout(Integer)

Timeout for confirmation from worker nodes when stopping the external backend. It is also possible to pass -1 to ensure the indefinite timeout. The unit is milliseconds.

spark.ext.h2o.external.hadoop.executable

hadoop

setExternalHadoopExecutable(String)

Name or path to path to a hadoop executable binary which is used to start external H2O backend on YARN.

spark.ext.h2o.external.extra.jars

None

setExternalExtraJars(String)

setExternalExtraJars(String[])

Comma-separated paths to jars that will be placed onto classpath of each H2O node.

spark.ext.h2o.external.communication.compression

SNAPPY

setExternalCommunicationCompression(String)

The type of compression used for data transfer between Spark and H2O node. Possible values are NONE, DEFLATE, GZIP, SNAPPY.

H2OConf getter can be derived from the corresponding setter. All getters are parameter-less. If the type of the property is Boolean, the getter is prefixed with is (E.g. setReplEnabled() -> isReplEnabled()). Property getters of other types do not have any prefix and start with lowercase (E.g. setUserName(String) -> userName for Scala, userName() for Python).