在linux系统上，如何安装Elasticsearch？

1.问题描述

当尝试连接时报错，报错内容为：
elastic_transport.ConnectionError: Connection error caused by: ConnectionError(Connection error caused by: NewConnectionError(<urllib3.connection.HTTPConnection object at 0x7fd808b179d0>: Failed to establish a new connection: [Errno 111] Connection refused))

这个错误表明你的Python脚本无法连接到Elasticsearch服务。错误ConnectionRefusedError: [Errno 111] Connection refused通常意味着：

1. Elasticsearch服务没有运行

2. Elasticsearch运行在不同的端口或主机上

3. 防火墙或网络设置阻止了连接

2.解决方案

（1）首先确保Elasticsearch正在运行

在终端运行：

sudo systemctl status elasticsearch

提示系统上没有安装Elasticsearch服务

（2）接下来安装Elasticsearch

对于Ubuntu/Debian系统，在终端执行下列代码：

wget -qO - https://artifacts.elastic.co/GPG-KEY-elasticsearch | sudo apt-key add -
sudo apt-get install apt-transport-https
echo "deb https://artifacts.elastic.co/packages/7.x/apt stable main" | sudo tee -a /etc/apt/sources.list.d/elastic-7.x.list
sudo apt-get update && sudo apt-get install elasticsearch

(3)启动并启用Elasticsearch服务

sudo systemctl daemon-reload
sudo systemctl enable elasticsearch
sudo systemctl start elasticsearch

(4)验证安装

curl -X GET "localhost:9200/"

当看到类似这样的输出说明就可以了：

{"name" : "user-R8424-G12","cluster_name" : "elasticsearch","cluster_uuid" : "OSRkQoNcSHWTfTkk3UiJlw","version" : {"number" : "7.17.28","build_flavor" : "default","build_type" : "deb","build_hash" : "xxxxx","build_date" : "2025-02-20T09:05:31.349013687Z","build_snapshot" : false,"lucene_version" : "8.11.3","minimum_wire_compatibility_version" : "6.8.0","minimum_index_compatibility_version" : "6.0.0-beta1"},"tagline" : "You Know, for Search"
}

(5)安装完成后，回到你的Python程序，确保你的连接代码使用的是正确的地址：

from elasticsearch import Elasticsearch# 对于本地安装
es = Elasticsearch("http://localhost:9200")# 对于Docker安装（如果Docker运行在另一台机器）
# es = Elasticsearch("http://your-host-ip:9200")# 测试连接
if es.ping():print("成功连接到Elasticsearch")
else:print("无法连接到Elasticsearch")