安裝環境 centos7.2 64位  openJDK1.8 

要求非root使用者執行  ./elasticsearch

報錯：

 max virtual memory areas vm.max_map_count [65530] likely too low, increase to at least [262144]  
  
max file descriptors [4096] for elasticsearch process likely too low, increase to at least [65536] 

解決辦法：

修改配置檔案：

sudo vim /etc/sysctl.conf

vm.max_map_count=262144

或：sudo sysctl -w vm.max_map_count=655360

sudo vim /etc/security/limits.conf

加入兩行：

username hard nofile 65536  
username soft nofile 65536  

叢集配置：

修改配置檔案config/elasticsearch.yml

假設配置2臺伺服器

cluster.name: my-application
node.name: node-1

network.host: 192.168.10.141
network.bind_host: 192.168.10.141
network.publish_host: 192.168.10.141

node.master: true
node.data: true

http.port: 9200
http.enabled: true
http.cors.enabled: true
http.cors.allow-origin: "*"

discovery.zen.ping.unicast.hosts: ["192.168.10.1","192.168.10.2"]

----------------------------------------------------------------------

cluster.name: my-application

node.name: node-2
network.host: 192.168.10.2
network.bind_host: 192.168.10.2
network.publish_host: 192.168.10.2
http.port: 9201
node.master: false
node.data: true

http.enabled: true
http.cors.enabled: true

http.cors.allow-origin: "*"

discovery.zen.ping.unicast.hosts: ["192.168.10.1","192.168.10.2"]

由於es5對head支援不友好，所以只能通過API來觀察伺服器狀態了。別安裝x-pack了，如果安裝了以後就需要你輸入使用者名稱密碼，java api裡面還不知道如何輸入

http://192.168.0.x:9201/_nodes/stats?pretty

maven依賴：

https://www.elastic.co/guide/en/elasticsearch/client/java-api/current/_maven_repository.html

Java api 呼叫程式碼：

public class ElasticsearchTools {
    private static String clustername="my-application";//es叢集
    private static String ip = "192.168.0.x";
    private static String ip2 = "192.168.0.x";
    private static int port = 9300;
    
    
    public static boolean addDocument(JSONObject object, String index, String type, String id) {
    TransportClient client = null;
        try {
        Settings settings = Settings.builder()
               .put("cluster.name", clustername).put("client.transport.sniff", true).build();
        client = new PreBuiltTransportClient(settings).addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName(ip), port)).addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName(ip2), port));