HugeGraph-Computer Quick Start

1 HugeGraph-Computer Overview

The HugeGraph-Computer is a distributed graph processing system for HugeGraph (OLAP). It is an implementation of Pregel. It runs on a Kubernetes(K8s) framework.(It focuses on supporting graph data volumes of hundreds of billions to trillions, using disk for sorting and acceleration, which is one of the biggest differences from Vermeer)

Features

• Support distributed MPP graph computing, and integrates with HugeGraph as graph input/output storage.
• Based on the BSP (Bulk Synchronous Parallel) model, an algorithm performs computing through multiple parallel iterations; every iteration is a superstep.
• Auto memory management. The framework will never be OOM(Out of Memory) since it will split some data to disk if it doesn’t have enough memory to hold all the data.
• The part of edges or the messages of super node can be in memory, so you will never lose it.
• You can load the data from HDFS or HugeGraph, or any other system.
• You can output the results to HDFS or HugeGraph, or any other system.
• Easy to develop a new algorithm. You just need to focus on vertex-only processing just like as in a single server, without worrying about message transfer and memory/storage management.

2 Dependency for Building/Running

2.1 Install Java 11 (JDK 11)

Must use ≥ Java 11 to run Computer, and configure by yourself.

Be sure to execute the java -version command to check the jdk version before reading

3 Get Started

3.1 Run PageRank algorithm locally

To run the algorithm with HugeGraph-Computer, you need to install Java 11 or later versions.

You also need to deploy HugeGraph-Server and Etcd.

There are two ways to get HugeGraph-Computer:

• Download the compiled tarball
• Clone source code then compile and package

3.1.1 Download the compiled archive

Download the latest version of the HugeGraph-Computer release package:

wget https://downloads.apache.org/incubator/hugegraph/${version}/apache-hugegraph-computer-incubating-${version}.tar.gz
tar zxvf apache-hugegraph-computer-incubating-${version}.tar.gz -C hugegraph-computer

3.1.2 Clone source code to compile and package

Clone the latest version of HugeGraph-Computer source package:

$ git clone https://github.com/apache/hugegraph-computer.git

Compile and generate tar package:

cd hugegraph-computer
mvn clean package -DskipTests

3.1.3 Start master node

You can use -c parameter specify the configuration file, more computer config please see:Computer Config Options

cd hugegraph-computer
bin/start-computer.sh -d local -r master

3.1.4 Start worker node

bin/start-computer.sh -d local -r worker

3.1.5 Query algorithm results

3.1.5.1 Enable OLAP index query for server

If the OLAP index is not enabled, it needs to be enabled. More reference: modify-graphs-read-mode

PUT http://localhost:8080/graphs/hugegraph/graph_read_mode

"ALL"

3.1.5.2 Query page_rank property value:

curl "http://localhost:8080/graphs/hugegraph/graph/vertices?page&limit=3" | gunzip

3.2 Run PageRank algorithm in Kubernetes

To run an algorithm with HugeGraph-Computer, you need to deploy HugeGraph-Server first

3.2.1 Install HugeGraph-Computer CRD

# Kubernetes version >= v1.16
kubectl apply -f https://raw.githubusercontent.com/apache/hugegraph-computer/master/computer-k8s-operator/manifest/hugegraph-computer-crd.v1.yaml

# Kubernetes version < v1.16
kubectl apply -f https://raw.githubusercontent.com/apache/hugegraph-computer/master/computer-k8s-operator/manifest/hugegraph-computer-crd.v1beta1.yaml

3.2.2 Show CRD

kubectl get crd

NAME                                        CREATED AT
hugegraphcomputerjobs.hugegraph.apache.org   2021-09-16T08:01:08Z

3.2.3 Install hugegraph-computer-operator&etcd-server

kubectl apply -f https://raw.githubusercontent.com/apache/hugegraph-computer/master/computer-k8s-operator/manifest/hugegraph-computer-operator.yaml

3.2.4 Wait for hugegraph-computer-operator&etcd-server deployment to complete

kubectl get pod -n hugegraph-computer-operator-system

NAME                                                              READY   STATUS    RESTARTS   AGE
hugegraph-computer-operator-controller-manager-58c5545949-jqvzl   1/1     Running   0          15h
hugegraph-computer-operator-etcd-28lm67jxk5                       1/1     Running   0          15h

3.2.5 Submit a job

More computer crd please see: Computer CRD

More computer config please see: Computer Config Options

cat <<EOF | kubectl apply --filename -
apiVersion: hugegraph.apache.org/v1
kind: HugeGraphComputerJob
metadata:
  namespace: hugegraph-computer-operator-system
  name: &jobName pagerank-sample
spec:
  jobId: *jobName
  algorithmName: page_rank
  image: hugegraph/hugegraph-computer:latest # algorithm image url
  jarFile: /hugegraph/hugegraph-computer/algorithm/builtin-algorithm.jar # algorithm jar path
  pullPolicy: Always
  workerCpu: "4"
  workerMemory: "4Gi"
  workerInstances: 5
  computerConf:
    job.partitions_count: "20"
    algorithm.params_class: org.apache.hugegraph.computer.algorithm.centrality.pagerank.PageRankParams
    hugegraph.url: http://${hugegraph-server-host}:${hugegraph-server-port} # hugegraph server url
    hugegraph.name: hugegraph # hugegraph graph name
EOF

3.2.6 Show job

kubectl get hcjob/pagerank-sample -n hugegraph-computer-operator-system

NAME               JOBID              JOBSTATUS
pagerank-sample    pagerank-sample    RUNNING

3.2.7 Show log of nodes

# Show the master log
kubectl logs -l component=pagerank-sample-master -n hugegraph-computer-operator-system

# Show the worker log
kubectl logs -l component=pagerank-sample-worker -n hugegraph-computer-operator-system

# Show diagnostic log of a job
# NOTE: diagnostic log exist only when the job fails, and it will only be saved for one hour.
kubectl get event --field-selector reason=ComputerJobFailed --field-selector involvedObject.name=pagerank-sample -n hugegraph-computer-operator-system

3.2.8 Show success event of a job

NOTE: it will only be saved for one hour

kubectl get event --field-selector reason=ComputerJobSucceed --field-selector involvedObject.name=pagerank-sample -n hugegraph-computer-operator-system

3.2.9 Query algorithm results

If the output to Hugegraph-Server is consistent with Locally, if output to HDFS, please check the result file in the directory of /hugegraph-computer/results/{jobId} directory.

4. Built-In algorithms document

4.1 Supported algorithms list:

Centrality Algorithm:

• PageRank
• BetweennessCentrality
• ClosenessCentrality
• DegreeCentrality

Community Algorithm:

• ClusteringCoefficient
• Kcore
• Lpa
• TriangleCount
• Wcc

Path Algorithm:

• RingsDetection
• RingsDetectionWithFilter

More algorithms please see: Built-In algorithms

4.2 Algorithm describe

TODO

5 Algorithm development guide

TODO

6 Note

• If some classes under computer-k8s cannot be found, you need to execute mvn compile in advance to generate corresponding classes.