一、安装elasticsearch

1. 环境

2. 安装docker
3. 拉取elasticsearch
   打开docker官方仓库，搜索elasticsearch以查看需要下载的版本，拉取镜像的时候，官方推荐要指定版本号
   https://hub.docker.com
   
   搜索es
   
   
   获取镜像
   
   
   获取版本
   
   
   获取对应版本

[root@master ~]# docker pull elasticsearch:7.4.2
7.4.2: Pulling from library/elasticsearch
d8d02d457314: Pull complete 
f26fec8fc1eb: Pull complete 
8177ad1fe56d: Pull complete 
d8fdf75b73c1: Pull complete 
47ac89c1da81: Pull complete 
fc8e09b48887: Pull complete 
367b97f47d5c: Pull complete 
Digest: sha256:543bf7a3d61781bad337d31e6cc5895f16b55aed4da48f40c346352420927f74
Status: Downloaded newer image for elasticsearch:7.4.2
docker.io/library/elasticsearch:7.4.2

4. 查看镜像

[root@master ~]# docker images
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
elasticsearch       7.4.2               b1179d41a7b4        2 weeks ago         855MB

5. 创建容器

[root@master ~]# docker run -d -p 9200:9200 -p 9300:9300 --name elasticsearch elasticsearch:7.4.2
28e360177e4a45a0ae0ed6e5f8e3eefc385bc71718b4293e65bc78efb59e6e93
[root@master ~]# docker ps
CONTAINER ID        IMAGE                 COMMAND                  CREATED             STATUS              PORTS                                            NAMES
28e360177e4a        elasticsearch:7.4.2   "/usr/local/bin/dock…"   10 seconds ago      Up 9 seconds        0.0.0.0:9200->9200/tcp, 0.0.0.0:9300->9300/tcp   elasticsearch

--name 名称 给容器起个名字
-p 外部访问端口:容器端口 9200是供htpp访问端口，9300是供tcp访问的端口，如果不做端口映射，浏览器就不能访问elasticsearch的服务

6. 修改配置

# 启动容器
[root@master ~]# docker start c85dca5150d8 

# 进入容器
[root@master ~]# docker exec -it c85dca5150d8 /bin/bash

7. 访问测试

[root@master ~]# curl http://192.168.56.101:9200
{
  "name" : "I7hHCsK",
  "cluster_name" : "docker-cluster",
  "cluster_uuid" : "3sH4lSgDSjeSiJClo-wZBg",
  "version" : {
    "number" : "6.7.2",
    "build_flavor" : "default",
    "build_type" : "docker",
    "build_hash" : "56c6e48",
    "build_date" : "2019-04-29T09:05:50.290371Z",
    "build_snapshot" : false,
    "lucene_version" : "7.7.0",
    "minimum_wire_compatibility_version" : "5.6.0",
    "minimum_index_compatibility_version" : "5.0.0"
  },
  "tagline" : "You Know, for Search"
}

常见问题：

1. curl: (7) Failed connect to 192.168.56.101:9200; Connection refused

# 查看日志
[root@master ~]# docker logs -f c85dca5150d8 
# 发现错误
ERROR: [1] bootstrap checks failed
[1]: max virtual memory areas vm.max_map_count [65530] is too low, increase to at least [262144]

显示max_map_count的值太小了，需要设大到262144
修改：

# 设置max_map_count:
[root@master ~]# sysctl -w vm.max_map_count=262144
vm.max_map_count = 262144

# 重启容器
[root@master ~]# systemctl restart docker