8. 安装Elasticsearch

8.1. 说明

用于语料检索的服务器，使用到ik分词器插件。目录下的yml脚本支持集群搭建，但目前只使用了一个节点，安装在192.168.0.129这台机，以后可拓展。

8.2. yml脚本

---
- hosts: elasticsearchservers
  remote_user: root
  vars_files:
    - ../vars.yml

  tasks:
    - name: mkdir jdk directory  #创建安装目录
      file: path={{ INSTALL_DIR }} state=directory mode=0755
      
    - name: Create es group
      group: name=elastic state=present

    - name: Create es user
      user: name=elastic group=elastic

    - name: copy and unzip es
      unarchive:
        src: "{{ PLAYBOOK_DIR }}/files/elasticsearch-7.6.2-linux-x86_64.tar.gz"
        dest: "{{ INSTALL_DIR }}"

    - name: copy and unzip ik analysis
      copy:
        src: "{{ PLAYBOOK_DIR }}/files/elasticsearch-analysis-ik-7.6.2"
        dest: "{{ INSTALL_DIR }}/elasticsearch-7.6.2/plugins"

    - name: mkdir ditectory for logs data
      file:
        dest: "{{ ES_LOGS_PATH }}"
        mode: 0755
        state: directory
        owner: elastic
        group: elastic

    - name: mkdir ditectory for es data
      file:
        dest: "{{ ES_DATA_PATH }}"
        mode: 0755
        state: directory
        owner: elastic
        group: elastic

    - name: change owner and group
      file:
        path: "{{ INSTALL_DIR }}/elasticsearch-7.6.2"
        owner: elastic
        group: elastic
        recurse: yes

    - name: make elastic permission
      file:
        path: "{{ INSTALL_DIR }}/elasticsearch-7.6.2"
        mode: "a+x"
        recurse: yes

    - name: update limits.conf
      lineinfile:
        dest: /etc/security/limits.conf
        insertafter: "{{ item.position }}"
        line: "{{ item.value }}"
        state: present
      with_items:
        - { position: EOF, value: "* soft nofile 65535" }
        - { position: EOF, value: "* hard nofile 65535" }

    - name: install configuration file for es
      template:
        src: "{{ PLAYBOOK_DIR }}/elasticsearch/templates/elasticsearch.yml.j2"
        dest: "{{ INSTALL_DIR }}/elasticsearch-7.6.2/config/elasticsearch.yml"

    - name: Copy service script
      template:
        src: "{{ PLAYBOOK_DIR }}/elasticsearch/templates/elasticsearch.service.j2"
        dest: /usr/lib/systemd/system/elasticsearch.service
        owner: root
        group: root
        mode: "u=rw,g=r,o=r"

    - name: reload systemctl
      shell: systemctl daemon-reload

    - name: source env
      shell: source ~/.bashrc

    - name: firewarld add 9200
      firewalld:
        port: 9200/tcp
        permanent: true
        immediate: true
        zone: public
        state: enabled
    - name: firewarld add 9300
      firewalld:
        port: 9300/tcp
        permanent: true
        immediate: true
        zone: public
        state: enabled

    - name: cert util
      shell: "{{ INSTALL_DIR }}/elasticsearch-7.6.2/bin/elasticsearch-certutil cert -out config/elastic-certificates.p12 -pass \"\""
      run_once: true

    - name: change certificate owner and group
      file:
        path: "{{ INSTALL_DIR }}/elasticsearch-7.6.2/config/elastic-certificates.p12"
        owner: elastic
        group: elastic
      run_once: true

    - name: start es
      service:
        name: elasticsearch.service
        state: started
      run_once: true
      tags:
        - start elasticsearch

7.3. j2模板配置

7.3.1 elasticsearch.yml.j2

节点配置文件

# ======================== Elasticsearch Configuration =========================
#
# NOTE: Elasticsearch comes with reasonable defaults for most settings.
#       Before you set out to tweak and tune the configuration, make sure you
#       understand what are you trying to accomplish and the consequences.
#
# The primary way of configuring a node is via this file. This template lists
# the most important settings you may want to configure for a production cluster.
#
# Please consult the documentation for further information on configuration options:
# https://www.elastic.co/guide/en/elasticsearch/reference/index.html
#
# ---------------------------------- Cluster -----------------------------------
#
# Use a descriptive name for your cluster:
#
cluster.name: {{ ES_CLUSTER_NAME }}
#
# ------------------------------------ Node ------------------------------------
#
# Use a descriptive name for the node:
#
node.name: {{ es_node_name }}
node.master: {{ es_node_master }}
#
# Add custom attributes to the node:
#
#node.rack: r1
#
# ----------------------------------- Paths ------------------------------------
#
# Path to directory where to store the data (separate multiple locations by comma):
#
path.data: {{ ES_DATA_PATH }}
#
# Path to log files:
#
path.logs: {{ ES_LOGS_PATH }}
#
# ----------------------------------- Memory -----------------------------------
#
# Lock the memory on startup:
#
#bootstrap.memory_lock: true
#
# Make sure that the heap size is set to about half the memory available
# on the system and that the owner of the process is allowed to use this
# limit.
#
# Elasticsearch performs poorly when the system is swapping the memory.
#
# ---------------------------------- Network -----------------------------------
#
# Set the bind address to a specific IP (IPv4 or IPv6):
#
network.host: {{ ansible_default_ipv4.address }}
#
# Set a custom port for HTTP:
#
http.port: 9200
transport.tcp.port: 9300
transport.tcp.compress: true
#
# For more information, consult the network module documentation.
#
# --------------------------------- Discovery ----------------------------------
#
# Pass an initial list of hosts to perform discovery when this node is started:
# The default list of hosts is ["127.0.0.1", "[::1]"]
#
discovery.seed_hosts: [{% set comma = joiner(",") %}
{% for item in groups['elasticsearchservers'] -%}
    {{ comma() }}"{{ hostvars[item].ansible_default_ipv4.address }}"
{%- endfor %}
]
#
# Bootstrap the cluster using an initial set of master-eligible nodes:
#
cluster.initial_master_nodes: ["{{ hostvars[groups['elasticsearchservers'][0]].ansible_default_ipv4.address }}"]
#
# For more information, consult the discovery and cluster formation module documentation.
#
# ---------------------------------- Gateway -----------------------------------
#
# Block initial recovery after a full cluster restart until N nodes are started:
#
#gateway.recover_after_nodes: 3
#
# For more information, consult the gateway module documentation.
#
# ---------------------------------- Various -----------------------------------
#
# Require explicit names when deleting indices:
#
#action.destructive_requires_name: true
thread_pool.write.queue_size: 1000
xpack.security.enabled: true
xpack.monitoring.enabled: true
xpack.monitoring.collection.enabled: true
xpack.security.transport.ssl.enabled: true
xpack.security.transport.ssl.verification_mode: certificate
xpack.security.transport.ssl.keystore.path: elastic-certificates.p12
xpack.security.transport.ssl.truststore.path: elastic-certificates.p12

需注意的是，在elasticsearch.yml这个文件里有两个属性discovery.seed_hosts和cluster.initial_master_nodes需要使用IP地址而不能使用域名，否则启用会找不到主节点。

7.3.2 elasticsearch.service.j2

[Unit]
Description=Elasticsearch
Documentation=http://www.elastic.co
Wants=network-online.target
After=network-online.target

[Service]
Environment=ES_HOME={{ INSTALL_DIR }}/elasticsearch-7.6.2/
Environment=ES_PID_DIR={{ INSTALL_DIR }}/elasticsearch-7.6.2/
EnvironmentFile=-/etc/sysconfig/elasticsearch
WorkingDirectory={{ INSTALL_DIR }}/elasticsearch-7.6.2/

User=elastic
Group=elastic

ExecStart={{ INSTALL_DIR }}/elasticsearch-7.6.2/bin/elasticsearch -p ${ES_PID_DIR}/elasticsearch.pid

StandardOutput=journal
StandardError=inherit
LimitNOFILE=65536
LimitMEMLOCK=infinity
TimeoutStopSec=0
KillSignal=SIGTERM
SendSIGKILL=no
SuccessExitStatus=143

[Install]
WantedBy=multi-user.target

7.4. 运行ansible-playbook

ansible-playbook -i /etc/ansible/hosts elasticsearch/main.yml

7.5. 安装成功

若安装成功，则能看到最后一行显示节点状态[es-1] started

image.png

7.6. 设置密码

从Elasticsearch 7开始，为提高安全性，安全认证已免费开放，需要使用交互式命令进行设置密码。

/home/tools/elasticsearch-7.6.2/bin/elasticsearch-setup-passwords interactive

输入完命令后启动有点慢，然后出现以下提示，输入y，按提示输入密码即可。

image.png

7.7. 查看节点状态

浏览器输入地址http://192.168.0.129:9200/，根据提示输入用户名（elastic）和密码可看到节点相关信息

7.8. 搭建集群

该小节为集群搭建步骤，第一个脚本是启动主节点，start.yml脚本是把生成的证书和配置复制到其他节点的同目录下，然后再启动节点。

---
- hosts: elasticsearchservers
  remote_user: root
  vars_files:
    - ../vars.yml

  tasks:
    - name: install rsync
      yum:
        name: rsync
        state: present
    - name: copy all config files except elasticsearch.yml
      synchronize:
        src: "{{ INSTALL_DIR }}/elasticsearch-7.6.2/config"
        dest: "{{ INSTALL_DIR }}/elasticsearch-7.6.2"
        rsync_opts:
          - "--exclude=elasticsearch.yml"
      when: inventory_hostname != groups['elasticsearchservers'][0]
      
    - name: start es
      service:
        name: elasticsearch.service
        state: started
      when: inventory_hostname != groups['elasticsearchservers'][0]
      tags:
        - start elasticsearch