ONgDB項目是neo4j企業版的一個開源分支。另外ONgDB的發起組織也在快速更新。目前最新是3.6.0版本，與企業版neo4j-3.6.0版本功能基本一致。目前企業版neo4j已經更新到4.0版本，最大的特點是支持分庫操作，ONgDB還不支持分庫操作。
一、安裝虛擬機
使用VMware虛擬機安裝CentOS7，搭建三個節點的集羣。
CentOS7是服務器常用的常用的操作系統，一般安裝好系統之後JDK8默認就安裝了。三臺機器用戶名均爲ongdb，密碼123456。虛擬機裝好之後繼續操作。
1、配置hosts
vim /etc/hosts
# 新增如下內容
192.168.91.128 node-1
192.168.91.129 node-2
192.168.91.130 node-3
2、配置可打開文件數
vim /etc/security/limits.conf
# 新增如下內容
neo4j soft nofile 40000
neo4j hard nofile 40000
二、關閉防火牆
# 查看防火牆狀態
systemctl status firewalld.service
# 關閉防火牆
systemctl disable firewalld.service
三、配置互信
1、修改SSH配置文件
vim /etc/ssh/sshd_config
# 找到下列行 去掉註釋井號#
RSAAuthentication yes //字面意思..允許RSA認證
PubkeyAuthentication yes //允許公鑰認證
AuthorizedKeysFile .ssh/authorized_keys //公鑰存放在.ssh/au..文件中
# 保存退出。
# 修改後需要重啓ssh
systemctl restart sshd
# 分別在host1，host2和host3上執行上述命令。
2、生成密碼對
ssh-keygen -t rsa
# 直接回車幾次，可在默認路徑~/.ssh/下生成私鑰idrsa公鑰idrsa.pub。
# 分別在host1，host2和host3上執行上述命令
3、 生成authorized_keys
# 將host2、host3的公鑰傳到host1上。
# 在host2上輸入
scp /home/ongdb/.ssh/id_rsa.pub ongdb@host1:~/.ssh/id_rsa.pub.host2
# 在host3上輸入
scp /home/ongdb/.ssh/id_rsa.pub ongdb@host1:~/.ssh/id_rsa.pub.host3
# 以上命令目前還需要輸入目標機用戶密碼。
# 在host1上輸入
cd ~/.ssh/
ls
# 查看idrsa.pub.host2、idrsa.pub.host3是否已經傳輸過來。
$ cat id_rsa.pub >> authorized_keys
$ cat id_rsa.pub.host2 >> authorized_keys
$ cat id_rsa.pub.host3 >> authorized_keys
# 生成authorized_keys。
# 給authorized_keys修改權限
chmod 644 authorized_keys
# 利用scp把該文件傳送到host2、host3的.ssh/下
scp authorized_keys hadoop@host2:~/.ssh/
scp authorized_keys hadoop@host3:~/.ssh/
4、 驗證
# 測試在host1下輸入
$ssh host2
$exit
$ssh host3
$exit
# 應該都不需要密碼。 這三個互聯都應該不需要密碼。
四、節點修改密碼
節點在啓動之後必須要先進shell修改密碼，首次進入默認的用戶密碼都是neo4j。
[ongdb@node-1 ongdb-node-1]$ bin/cypher-shell
username: neo4j
password: *****
Connected to Neo4j 3.5.16 at bolt://localhost:7687 as user neo4j.
Type :help for a list of available commands or :exit to exit the shell.
Note that Cypher queries must end with a semicolon.
neo4j> CALL dbms.changePassword('123456');
0 rows available after 320 ms, consumed after another 2 ms
neo4j>
五、配置兩個CORE節點
ongdb-node-1配置
#*****************************************************************
# Network connector configuration
#*****************************************************************
dbms.connectors.default_listen_address=0.0.0.0
dbms.connectors.default_advertised_address=node-1
# Bolt connector
dbms.connector.bolt.enabled=true
#dbms.connector.bolt.tls_level=OPTIONAL
dbms.connector.bolt.listen_address=:7687
# HTTP Connector. There can be zero or one HTTP connectors.
dbms.connector.http.enabled=true
dbms.connector.http.listen_address=:7474
# HTTPS Connector. There can be zero or one HTTPS connectors.
dbms.connector.https.enabled=true
dbms.connector.https.listen_address=:7473
#*****************************************************************
# Causal Clustering Configuration
#*****************************************************************
dbms.mode=CORE
causal_clustering.minimum_core_cluster_size_at_formation=2
causal_clustering.minimum_core_cluster_size_at_runtime=2
causal_clustering.initial_discovery_members=node-1:5000,node-2:5001
causal_clustering.discovery_listen_address=:5000
# Remote debugging
dbms.jvm.additional=-agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=5005
# algo|apoc|* plugins
dbms.security.procedures.unrestricted=algo.*,apoc.*,*
apoc.export.file.enabled=true
apoc.import.file.enabled=true
#********************************************************************
# Prometheus monitor
#********************************************************************
# Enable the Prometheus endpoint. Default is 'false'.
metrics.prometheus.enabled=true
# The default is localhost:2004.
metrics.prometheus.endpoint=localhost:2004
ongdb-node-2配置
#*****************************************************************
# Network connector configuration
#*****************************************************************
dbms.connectors.default_listen_address=0.0.0.0
dbms.connectors.default_advertised_address=node-2
# Bolt connector
dbms.connector.bolt.enabled=true
#dbms.connector.bolt.tls_level=OPTIONAL
dbms.connector.bolt.listen_address=:7687
# HTTP Connector. There can be zero or one HTTP connectors.
dbms.connector.http.enabled=true
dbms.connector.http.listen_address=:7474
# HTTPS Connector. There can be zero or one HTTPS connectors.
dbms.connector.https.enabled=true
dbms.connector.https.listen_address=:7473
#*****************************************************************
# Causal Clustering Configuration
#*****************************************************************
dbms.mode=CORE
causal_clustering.minimum_core_cluster_size_at_formation=2
causal_clustering.minimum_core_cluster_size_at_runtime=2
causal_clustering.initial_discovery_members=node-1:5000,node-2:5001
causal_clustering.discovery_listen_address=:5000
# Remote debugging
dbms.jvm.additional=-agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=5005
# algo|apoc|* plugins
dbms.security.procedures.unrestricted=algo.*,apoc.*,*
apoc.export.file.enabled=true
apoc.import.file.enabled=true
#********************************************************************
# Prometheus monitor
#********************************************************************
# Enable the Prometheus endpoint. Default is 'false'.
metrics.prometheus.enabled=true
# The default is localhost:2004.
metrics.prometheus.endpoint=localhost:2004
六、增加一個只讀READ_REPLICA節點
ongdb-node-3配置
#*****************************************************************
# Network connector configuration
#*****************************************************************
dbms.connectors.default_listen_address=0.0.0.0
dbms.connectors.default_advertised_address=node-3
# Bolt connector
dbms.connector.bolt.enabled=true
#dbms.connector.bolt.tls_level=OPTIONAL
dbms.connector.bolt.listen_address=:7687
# HTTP Connector. There can be zero or one HTTP connectors.
dbms.connector.http.enabled=true
dbms.connector.http.listen_address=:7474
# HTTPS Connector. There can be zero or one HTTPS connectors.
dbms.connector.https.enabled=true
dbms.connector.https.listen_address=:7473
#*****************************************************************
# Causal Clustering Configuration
#*****************************************************************
dbms.mode=READ_REPLICA
causal_clustering.minimum_core_cluster_size_at_formation=2
causal_clustering.minimum_core_cluster_size_at_runtime=2
causal_clustering.initial_discovery_members=node-1:5000,node-2:5001,node-3:5002
causal_clustering.discovery_listen_address=:5002
# Remote debugging
dbms.jvm.additional=-agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=5005
# algo|apoc|* plugins
dbms.security.procedures.unrestricted=algo.*,apoc.*,*
apoc.export.file.enabled=true
apoc.import.file.enabled=true
#********************************************************************
# Prometheus monitor
#********************************************************************
# Enable the Prometheus endpoint. Default is 'false'.
metrics.prometheus.enabled=true
# The default is localhost:2004.
metrics.prometheus.endpoint=localhost:2004
七、檢驗apoc和algo插件
CALL algo.list()
CALL apoc.config.list()
八、查看集羣成員角色
CALL dbms.cluster.overview()
CALL dbms.cluster.role()
kill掉節點2，之後再看一下：
九、更多信息
apoc與Neo4j的版本對應關係及下載
algo與Neo4j的版本對應關係及下載
自定義插件包
ONgDB下載 - 本次測試使用的版本3.5.16
相關插件包與配置文件的下載