Uniffle Coordinator Guide

Uniffle is a unified remote shuffle service for compute engines, the role of coordinator is responsibility for collecting status of shuffle server and doing the assignment for the job.

Deploy

This document will introduce how to deploy Uniffle coordinators.

Steps

1. unzip package to RSS_HOME

2. update RSS_HOME/bin/rss-env.sh, eg,

     JAVA_HOME=<java_home>
     HADOOP_HOME=<hadoop home>
     XMX_SIZE="16g"

3. update RSS_HOME/conf/coordinator.conf, eg,

     rss.rpc.server.port 19999
     rss.jetty.http.port 19998
     rss.coordinator.server.heartbeat.timeout 30000
     rss.coordinator.app.expired 60000
     rss.coordinator.shuffle.nodes.max 5
     # enable dynamicClientConf, and coordinator will be responsible for most of client conf
     rss.coordinator.dynamicClientConf.enabled true
     # config the path of client conf
     rss.coordinator.dynamicClientConf.path <RSS_HOME>/conf/dynamic_client.conf
     # config the path of excluded shuffle server
     rss.coordinator.exclude.nodes.file.path <RSS_HOME>/conf/exclude_nodes

4. update <RSS_HOME>/conf/dynamic_client.conf, rss client will get default conf from coordinator eg,

    # MEMORY_LOCALFILE_HDFS is recommandation for production environment
    rss.storage.type MEMORY_LOCALFILE_HDFS
    # multiple remote storages are supported, and client will get assignment from coordinator
    rss.coordinator.remote.storage.path hdfs://cluster1/path,hdfs://cluster2/path
    rss.writer.require.memory.retryMax 1200
    rss.client.retry.max 100
    rss.writer.send.check.timeout 600000
    rss.client.read.buffer.size 14m

5. update <RSS_HOME>/conf/exclude_nodes, coordinator will update excluded node by this file eg,

    # shuffleServer's ip and port, connected with "-"
    110.23.15.36-19999
    110.23.15.35-19996

6. start Coordinator

    bash RSS_HOME/bin/start-coordnator.sh

Configuration

Common settings

Property Name	Default	Description
rss.coordinator.server.heartbeat.timeout	30000	Timeout if can't get heartbeat from shuffle server
rss.coordinator.server.periodic.output.interval.times	30	The periodic interval times of output alive nodes. The interval sec can be calculated by (rss.coordinator.server.heartbeat.timeout/3 * rss.coordinator.server.periodic.output.interval.times). Default output interval is 5min.
rss.coordinator.assignment.strategy	PARTITION_BALANCE	Strategy for assigning shuffle server, PARTITION_BALANCE should be used for workload balance
rss.coordinator.app.expired	60000	Application expired time (ms), the heartbeat interval should be less than it
rss.coordinator.shuffle.nodes.max	9	The max number of shuffle server when do the assignment
rss.coordinator.dynamicClientConf.path	-	The path of configuration file which have default conf for rss client
rss.coordinator.exclude.nodes.file.path	-	The path of configuration file which have exclude nodes
rss.coordinator.exclude.nodes.check.interval.ms	60000	Update interval (ms) for exclude nodes
rss.coordinator.access.checkers	org.apache.uniffle.coordinator.AccessClusterLoadChecker	The access checkers will be used when the spark client use the DelegationShuffleManager, which will decide whether to use rss according to the result of the specified access checkers
rss.coordinator.access.loadChecker.memory.percentage	15.0	The minimal percentage of available memory percentage of a server
rss.coordinator.dynamicClientConf.enabled	false	whether to enable dynamic client conf, which will be fetched by spark client
rss.coordinator.dynamicClientConf.path	-	The dynamic client conf of this cluster and can be stored in HDFS or local
rss.coordinator.dynamicClientConf.updateIntervalSec	120	The dynamic client conf update interval in seconds
rss.coordinator.remote.storage.cluster.conf	-	Remote Storage Cluster related conf with format $clusterId,$key=$value, separated by ';'
rss.rpc.server.port	-	RPC port for coordinator
rss.jetty.http.port	-	Http port for coordinator
rss.coordinator.remote.storage.select.strategy	APP_BALANCE	Strategy for selecting the remote path
rss.coordinator.remote.storage.io.sample.schedule.time	60000	The time of scheduling the read and write time of the paths to obtain different HDFS
rss.coordinator.remote.storage.io.sample.file.size	204800000	The size of the file that the scheduled thread reads and writes
rss.coordinator.remote.storage.io.sample.access.times	3	The number of times to read and write HDFS files
rss.coordinator.startup-silent-period.enabled	false	Enable the startup-silent-period to reject the assignment requests for avoiding partial assignments. To avoid service interruption, this mechanism is disabled by default. Especially it's recommended to use in coordinator HA mode when restarting single coordinator.
rss.coordinator.startup-silent-period.duration	20000	The waiting duration(ms) when conf of rss.coordinator.startup-silent-period.enabled is enabled.

AccessClusterLoadChecker settings

Property Name	Default	Description
rss.coordinator.access.loadChecker.serverNum.threshold	-	The minimal required number of healthy shuffle servers when being accessed by client. And when not specified, it will use the required shuffle-server number from client as the checking condition. If there is no client shuffle-server number specified, the coordinator conf of rss.coordinator.shuffle.nodes.max will be adopted

AccessCandidatesChecker settings

AccessCandidatesChecker is one of the built-in access checker, which will allow user to define the candidates list to use rss.

Property Name	Default	Description
rss.coordinator.access.candidates.updateIntervalSec	120	Accessed candidates update interval in seconds, which is only valid when AccessCandidatesChecker is enabled.
rss.coordinator.access.candidates.path	-	Accessed candidates file path, the file can be stored on HDFS