Ansible实现主备模式的高可用(Keepalived)

前言

　　Ansible是一款极其简单的IT自动化运维工具，基于Python开发，集合了众多运维工具(puppet、cfengine、chef、func、fabric)的优点，实现了批量系统配置、批量程序部署、批量运行命令等功能。Ansible是基于模块工作的，本身没有批量部署的能力，真正具有批量部署的是Ansible所运行的模块，Ansible只是提供一种框架。Ansible主要承担的工作包括：配置管理、服务即时开通、应用部署、流程编排、监控告警、日志记录等。

　　Ansible的基本架构：

• 核心模块(Core Module)：在模块库(Module Library)中分为两块，一个是核心模块,另外一个就是自定义模块(Custom Modules)。核心模块中都是Ansible自带的模块，模块资源分发到远程节点使其执行特定任务或匹配一个特定的状态；
• 自定义模块(Custom Modules)：如果Ansible满足不了你所需求的模块，则在此处添加自定义化的模块；
• 插件(Plugins)：协助模块来完成某个功能；
• 剧本(Playbooks)：定义需要给远程主机执行的一系列任务；
• 连接插件(Connectior Plugins)：Ansible默认基于SSH连接到目标机器上执行操作的，但也支持不同的连接方法，此时需要连接插件来帮助我们完成连接；
• 主机清单(Host Inventory)：定义需要管理的主机，小型环境中我们只需要在host文件中写入主机的IP地址即可，但到了中大型环境我们有可能需要使用静态inventory或者动态主机清单来生成我们所需要执行的目标主机。

实验拓扑图

　　两台Nginx作为Web Proxy，配置实现KeepAlived做主备；后端两台Apache，一台部署Apache+PHP，一台部署Apache+MySQL。

搭建Ansible

[root@ansible ~]# systemctl stop firewalld.service
[root@ansible ~]# systemctl disable firewalld.serive
[root@ansible ~]# vim /etc/selinux/config
    ...
    SELINUX=disabled
    ...
[root@ansible ~]# init 6
[root@ansible ~]# ntpdate ntp1.aliyun.com
[root@ansible ~]# yum -y install ansible
[root@ansible ~]# vim /etc/ansible/hosts
    ...
    [hasrvs]
    192.168.4.117
    192.168.4.118
    [websrvs]
    192.168.4.119
    192.168.4.120
　　[php]
　　192.168.4.119
　　[mysql]
　　192.168.4.120
[root@ansible ~]# vim /etc/hosts
    ...
    192.168.4.117 nginx1
    192.168.4.118 nginx2
    192.168.4.119 apache1
    192.168.4.120 apache2
[root@ansible ~]# ssh-keygen -t rsa -N ''  #生成密钥对，实现ssh免密码登录
    Generating public/private rsa key pair.
    Enter file in which to save the key (/root/.ssh/id_rsa): 
    Created directory '/root/.ssh'.
    Your identification has been saved in /root/.ssh/id_rsa.
    Your public key has been saved in /root/.ssh/id_rsa.pub
[root@ansible ~]# ssh-copy-id -i .ssh/id_rsa.pub root@192.168.4.117  #复制公钥到各远程主机
[root@ansible ~]# ssh-copy-id -i .ssh/id_rsa.pub root@192.168.4.118
[root@ansible ~]# ssh-copy-id -i .ssh/id_rsa.pub root@192.168.4.119
[root@ansible ~]# ssh-copy-id -i .ssh/id_rsa.pub root@192.168.4.120

 测试连通性

[root@ansible ~]# ansible all -m ping
    192.168.4.117 | SUCCESS => {
        "changed": false, 
        "ping": "pong"
    }
    192.168.4.118 | SUCCESS => {
        "changed": false, 
        "ping": "pong"
    }
    192.168.4.120 | SUCCESS => {
        "changed": false, 
        "ping": "pong"
    }
    192.168.4.119 | SUCCESS => {
        "changed": false, 
        "ping": "pong"
    }

同步时间，关闭firewalld及selinux

[root@ansible ~]# ansible all -m shell -a 'echo "TZ='Asia/Shanghai'; export TZ" >> /etc/profile'
[root@ansible ~]# ansible all -m cron -a 'minute=*/5 job="/usr/sbin/ntpdate ntp1.aliyun.com &> /dev/null" name=UpdateTime'  #每隔3分钟同步一次时间
[root@ansible ~]# ansible all -m shell -a 'systemctl stop firewalld.service; systemctl disable firewalld.service; setenfore 0'

 配置Apache服务的roles

[root@ansible ~]# mkdir -pv /etc/ansible/roles/apache/{files,templates,tasks,handlers,vars,meta,default}  #创建相关目录
[root@ansible ~]# vim /etc/ansible/roles/apache/templates/vhost.conf.j2  #Apache主机模板
    <virtualhost *:80>
        ServerName www.test.org
        DirectoryIndex index.html index.php
        DocumentRoot /var/www/html
        ProxyRequests off
        ProxyPassMatch ^/(.*.php)$ fcgi://192.168.4.119:9000/var/www/html/$1
        ProxyPassMatch ^/(ping|status)$ fcgi://192.168.4.119:9000/$1
        <Directory />
        options FollowSymlinks
        Allowoverride None
        Require all granted
        </Directory>
    </virtualhost>
[root@ansible ~]# vim /etc/ansible/roles/apache/templates/index.html  #Apache主页
    <h1> This is {{ ansible_hostname }} </h1>
[root@ansible ~]# vim /etc/ansible/roles/apache/files/index.php
    <?php
        phpinfo();
    ?>
[root@ansible ~]# vim /etc/ansible/roles/apache/tasks/main.yml  #定义实现Apache的task
    - name: install apache
      yum: name=httpd state=latest
    - name: copy conf
      template: src=vhost.conf.j2 dest=/etc/httpd/conf.d/vhost.conf
    - name: copy index.html
      template: src=index.html dest=/var/www/html/index.html
    - name: copy index.php
      copy: src=index.php dest=/var/www/html/index.php
    - name: start httpd
      service: name=httpd state=started

配置php-fpm服务的roles

[root@ansible ~]# mkdir -pv /etc/ansible/roles/php-fpm/{files,templates,tasks,handlers,vars,meta,default}  #创建相关目录
[root@ansible ~]# cp /etc/php-fpm.d/www.conf /etc/ansible/roles/php-fpm/templates/www.conf.j2  #直接复制事先准备的配置模板
[root@ansible ~]# vim /etc/ansible/roles/php-fpm/templates/www.conf.j2
    #修改如下配置
    listem = 0.0.0.0:9000
    ;listen.allowed_clients = 127.0.0.1
    pm.status_path = /status
    ping.path = /ping
    ping.response = pong
[root@ansible ~]# vim /etc/ansible/roles/php-fpm/tasks/main.yml  #定义实现php-fpm的task
    - name: install php
      yum: name={{ item }} state=latest
      with_items:
      - php-fpm
      - php-mysql
      - php-mbstring
      - php-mcrypt
    - name: copy config
      template: src=www.conf.j2 dest=/etc/php-fpm.d/www.conf
    - name: create directory
      file: path=/var/lib/php/session group=apache owner=apache state=directory
    - name: start php-fpm
      service: name=php-fpm state=started

 配置MySQL服务的roles

[root@ansible ~]# mkdir -pv /etc/ansible/roles/mysql/{files,templates,tasks,handlers,vars,meta,default}  #创建相关目录
[root@ansible ~]# cp /etc/my.cnf /etc/ansible/roles/mysql/templates/my.cnf.j2  #复制事先准备的模板
[root@ansible ~]# vim /etc/ansible/roles/mysql/templates/my.cnf.j2
    #添加如下配置
    skip-name-resolve=ON
    innodb-file-per-table=ON
[root@ansible ~]# vim /etc/ansible/roles/mysql/tasks/main.yml  #定义实现MySQL的task
    - name: install mysql
      yum: name=mariadb-server state=latest
    - name: copy config
      template: src=my.cnf.j2 dest=/etc/my.cnf
    - name: start mysql
      service: name=mariadb state=started

配置Nginx服务的roles

[root@ansible ~]# mkdir -pv /etc/ansible/roles/nginx/{files,templates,tasks,handlers,vars,meta,default}  #创建相关目录
[root@ansible ~]# cp /etc/nginx/nginx.conf /etc/ansible/roles/nginx/templates/nginx.conf.j2  #复制事先准备的模板
[root@ansible ~]# vim /etc/ansible/roles/nginx/templates/nginx.conf.j2
　　#修改配置
    http {
        ...
        upstream websrvs {
            server 192.168.4.119:80;
            server 192.168.4.120:80;
            server 127.0.0.1:80 backup;
        }
        server {
        
            listen 80;
            include /etc/nginx/default.d/*.conf;
    
            location / {
                proxy_pass http://websrvs;
                proxy_set_header host $http_host;
                proxy_set_header X-Forward-For $remote_addr;
            }
            ...
        }
        ...
    }
[root@ansible ~]# vim /etc/ansible/roles/nginx/templates/localhost.conf.j2  #定义本地的Nginx服务
    server {
        listen 127.0.0.1:80;
        root /usr/share/nginx/html;
        index index.html;
    }
[root@ansible ~]# vim /etc/ansible/roles/nginx/templates/index.html
    <h1> Balance Server {{ ansible_hostname }} </h1>
[root@ansible ~]# vim /etc/ansible/roles/nginx/tasks/main.yml  #定义实现Nginx的task
    - name: install nginx
      yum: name=nginx state=latest
    - name: copy nginx conf
      template: src=nginx.conf.j2 dest=/etc/nginx/nginx.conf
    - name: copy local conf
      template: src=localhost.conf.j2 dest=/etc/nginx/conf.d/localhost.conf
    - name: copy index
      template: src=index.html dest=/usr/share/nginx/html/index.html
    - name: start nginx
      service: name=nginx state=started

 配置KeepAlived服务的roles

[root@ansible keepalived]# mkdir -pv /etc/ansible/roles/keepalived/{files,templates,tasks,handlers,vars,meta,default}  #创建相关目录
[root@ansible keepalived]# vim /etc/ansible/roles/keepalived/templates/keepalived.conf.j2  #KeepAlived配置文件
    global_defs {
           notification_email {
             root@localhost
           }
           notification_email_from keepalived@localhost
           smtp_server 127.0.0.1
           smtp_connect_timeout 30
           router_id {{ ansible_nodename }}
           vrrp_skip_check_adv_addr
           vrrp_mcast_group4 224.0.0.10
    }
    
    vrrp_instance VIP_1 {
        state {{ keepalived_role }}
        interface eno16777736
        virtual_router_id 1
        priority {{ keepalived_pri }}
        advert_int 1
        authentication {
            auth_type PASS
            auth_pass %&hhjj99
        }
        virtual_ipaddress {
        　　192.168.4.155/24 dev eno16777736 label eno16777736:0
        }
    }
[root@ansible keepalived]# vim /etc/ansible/hosts  #添加变量
        ...
    [hasrvs]
    192.168.4.117 keepalived_role=MASTER keepalived_pri=100
    192.168.4.118 keepalived_role=BACKUP keepalived_pri=99
    ...
[root@ansible keepalived]# vim /etc/ansible/roles/keepalived/tasks/main.yml  #定义实现Keepalived的task
    - name: install keepalived
      yum: name=keepalived state=latest
    - name: copy config
      template: src=keepalived.conf.j2 dest=/etc/keepalived/keepalived.conf
    - name: start keepalived
      service: name=keepalived state=started

 配置Apache+PHP服务的playbook

[root@ansible keepalived]# mkdir /etc/ansible/playbooks  #创建playbook存放目录
[root@ansible roles]# vim /etc/ansible/playbooks/ap1.yml  定义实现Apache+php-fpm的playbook
    - hosts: php
      remote_user: root
      roles:
      - apache
      - php-fpm
[root@ansible roles]# ansible-playbook --syntax-check /etc/ansible/playbooks/ap1.yml  #检查是否有语法错误
[root@ansible roles]# ansible-playbook /etc/ansible/playbooks/ap1.yml  #执行

配置Apache+MySQL服务的playbook

[root@ansible ~]# vim /etc/ansible/playbooks/ap2.yml
    - hosts: mysql
      remote_user: root
      roles:
      - apache
      - mysql
[root@ansible ~]# ansible-playbook --syntax-check /etc/ansibleplaybooks/ap2.yml
[root@ansible ~]# ansible-playbook /etc/ansibleplaybooks/ap2.yml

 配置Nginx+Keepalived服务的playbook

[root@ansible ~]# vim /etc/ansible/playbooks/ha.yml
    - hosts: hasrvs
      remote_user: root
      roles:
      - nginx
      - keepalived 
[root@ansible ~]# ansible-playbook --syntax-check /etc/ansible/playbooks/ha.yml 
[root@ansible ~]# ansible-playbook /etc/ansible/playbooks/ha.yml

 客户端测试访问

[root@client ~]# vim /etc/hosts
    ...
    192.168.4.155 www.test.org
    ...
[root@client ~]# for i in {1..10};do curl http://www.test.org;done
    <h1> This is apache2 </h1>
    <h1> This is apache1 </h1>
    <h1> This is apache2 </h1>
    <h1> This is apache1 </h1>
    <h1> This is apache2 </h1>
    <h1> This is apache1 </h1>
    <h1> This is apache2 </h1>
    <h1> This is apache1 </h1>
    <h1> This is apache2 </h1>
    <h1> This is apache1 </h1>

小插曲：

　　[root@ansible ~]# ansible all -m ping --list-hosts
　　ERROR! Unexpected Exception, this is probably a bug: (cryptography 0.8.2 (/usr/lib64/python2.7/site-packages), Requirement.parse('cryptography>=1.1'))

　　运行ansible命令时报错，python的cryptography版本必须>=1.1。

　　解决办法：

　　[root@ansible ~]# yum -y install python-pip

　　[root@ansible ~]# pip install --upgrade cryptography