Python自動化運維之ansible的Haproxy+LAMP+Nagios經典案例角色說明

一 haproxy角色

1 點睛

haproxy角色主要實現了haproxy平臺的部署、配置功能。

2 roles/haproxy/tasks

---
# This role installs HAProxy and configures it.

- name: Download and install haproxy and socat
  yum: name={{ item }} state=present
  with_items:
  - haproxy
  - socat

- name: Configure the haproxy cnf file with hosts
  template: src=haproxy.cfg.j2 dest=/etc/haproxy/haproxy.cfg

3 說明

任務（tasks）定義了兩個功能，一爲安裝，二爲同步配置文件， 安裝使用了yum模塊，循環安裝haproxy、socat兩個工具，同時根據配置參數渲染roles/haproxy/templates/haproxy.cfg.j2模板文件，完成後同步到目標

主機/etc/haproxy/haproxy.cfg位置，狀態發生變化時重啓haproxy 服務，使之生效。

4 roles/haproxy/templates/haproxy.cfg.j2

global
    log         127.0.0.1 local2

    chroot      /var/lib/haproxy
    pidfile     /var/run/haproxy.pid
    maxconn     4000
    user        root
    group       root
    daemon

    # turn on stats unix socket
    stats socket /var/lib/haproxy/stats level admin

defaults
    mode                    {{ mode }}
    log                     global
    option                  httplog
    option                  dontlognull
    option http-server-close
    option forwardfor       except 127.0.0.0/8
    option                  redispatch
    retries                 3
    timeout http-request    10s
    timeout queue           1m
    timeout connect         10s
    timeout client          1m
    timeout server          1m
    timeout http-keep-alive 10s
    timeout check           10s
    maxconn                 3000

backend app
    {% for host in groups['lbservers'] %}
        listen {{ daemonname }} {{ hostvars[host]['ansible_' + iface].ipv4.address }}:{{ listenport }}
    {% endfor %}
    balance     {{ balance }}
    {% for host in groups['webservers'] %}
        server {{ hostvars[host].ansible_hostname }} {{ hostvars[host]['ansible_' + iface].ipv4.address }}:{{ httpd_port }}
    {% endfor %}

{{hostvars[host]['ansible_'+iface].ipv4.address}}實現了獲取網卡名變量iface（group_vars/lbservers中定義）的IPv4 IP地址。

二 web角色

1 點睛

web角色主要實現了php、php-mysql、git平臺部署及SELinux的配 置功能。

2 roles/web/tasks/main.yml

---
# This will install nagios

- name: install nagios
  yum: pkg={{ item }} state=present
  with_items:
   - nagios
   - nagios-plugins
   - nagios-plugins-nrpe
   - nagios-plugins-ping
   - nagios-plugins-ssh
   - nagios-plugins-http
   - nagios-plugins-mysql
   - nagios-devel
  notify: restart httpd

- name: create nagios config dir
  file: path=/etc/nagios/ansible-managed state=directory

- name: configure nagios
  copy: src=nagios.cfg dest=/etc/nagios/nagios.cfg
  notify: restart nagios

- name: configure localhost monitoring
  copy: src=localhost.cfg dest=/etc/nagios/objects/localhost.cfg
  notify: restart nagios

- name: configure nagios services
  copy: src=ansible-managed-services.cfg dest=/etc/nagios/

- name: create the nagios object files
  template: src={{ item + ".j2" }}
            dest=/etc/nagios/ansible-managed/{{ item }}
  with_items:
    - webservers.cfg
    - dbservers.cfg
    - lbservers.cfg
  notify: restart nagios

- name: start nagios
  service: name=nagios state=started enabled=yes

判斷sestatus變量（roles/common/tasks/main.yml中定義）返回的 rc（運行代碼）不等於0（失敗），則配置selinux httpd訪問遠程數據庫的權限，使用的是Ansible的seboolean模塊，該條語句等價於命令 行“setsebool httpd_can_network_connect_db 1”，其中“persistent=yes”表 示開機自啓動。

三 nagios角色

1 點睛 

nagios角色主要實現了nagios監控平臺的部署。

2 roles/nagios/tasks/main.yml

---
# This will install nagios

- name: install nagios
  yum: pkg={{ item }} state=present
  with_items:
   - nagios
   - nagios-plugins
   - nagios-plugins-nrpe
   - nagios-plugins-ping
   - nagios-plugins-ssh
   - nagios-plugins-http
   - nagios-plugins-mysql
   - nagios-devel
  notify: restart httpd

- name: create nagios config dir
  file: path=/etc/nagios/ansible-managed state=directory

- name: configure nagios
  copy: src=nagios.cfg dest=/etc/nagios/nagios.cfg
  notify: restart nagios

- name: configure localhost monitoring
  copy: src=localhost.cfg dest=/etc/nagios/objects/localhost.cfg
  notify: restart nagios

- name: configure nagios services
  copy: src=ansible-managed-services.cfg dest=/etc/nagios/

- name: create the nagios object files
  template: src={{ item + ".j2" }}
            dest=/etc/nagios/ansible-managed/{{ item }}
  with_items:
    - webservers.cfg
    - dbservers.cfg
    - lbservers.cfg
  notify: restart nagios

- name: start nagios
  service: name=nagios state=started enabled=yes

template分發多個模板文件時可以使用with_items來循環同步，變量與字符使用“+”號連接。