基本使用

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2023-12-01

说明

本部分包括 ansible 基本命令的演示

Ad Hoc 命令

环境准备

1. 控制节点安装 Ansible

# ansible --version
ansible 2.7.2
  config file = /etc/ansible/ansible.cfg
  configured module search path = [u'/root/.ansible/plugins/modules', u'/usr/share/ansible/plugins/modules']
  ansible python module location = /usr/lib/python2.7/site-packages/ansible
  executable location = /usr/bin/ansible
  python version = 2.7.5 (default, Sep 12 2018, 05:31:16) [GCC 4.8.5 20150623 (Red Hat 4.8.5-36)]

2. 被管节点网络可达

# for i in a b ; do ping server$i.example.com -c3; done

创建 Inventory 文件

1. 创建 hosts-basic-usage 文件，添加如下内容

[web]
servera.example.com

[sql]
serverb.example.com

2. 执行 ping 命令，测试 Inventory

# ansible -i hosts-basic-usage -m ping all
servera.example.com | UNREACHABLE! => {
    "changed": false,
    "msg": "Failed to connect to the host via ssh: Warning: Permanently added 'servera.example.com,10.66.208.131' (ECDSA) to the list of known hosts.\r\nAuthentication failed.\r\n",
    "unreachable": true
}

serverb.example.com | UNREACHABLE! => {
    "changed": false,
    "msg": "Failed to connect to the host via ssh: Could not create directory '/root/.ssh'.\r\nHost key verification failed.\r\n",
    "unreachable": true
}

生成 SSH Key，节点互信

1. 生成 Key

# ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /root/.ssh/id_rsa.
Your public key has been saved in /root/.ssh/id_rsa.pub.
The key fingerprint is:
SHA256:azG6KYPvwdspy/P3ZIFPHMwHMnUgxZFDpl9iMuJiZlA root@rhel7.example.com
The key's randomart image is:
+---[RSA 2048]----+
|    E   +=O+.    |
|   .     O+o     |
|  .   . + *.o    |
|   . . . B =     |
|    = . S =      |
|   = . . * .     |
|   .o . o +      |
|  ..=+ =.o       |
|   o*B*. ..      |
+----[SHA256]-----+

2. 拷贝 Key

# ssh-copy-id servera.example.com
# ssh-copy-id serverb.example.com

3. 执行 ping 命令

# ansible -i hosts-basic-usage -m ping all
serverb.example.com | SUCCESS => {
    "changed": false,
    "ping": "pong"
}
servera.example.com | SUCCESS => {
    "changed": false,
    "ping": "pong"
}

收集 Facts

# ansible -i hosts-basic-usage web -m setup
servera.example.com | SUCCESS => {
    "ansible_facts": {
        "ansible_all_ipv4_addresses": [
            "10.66.208.131"
        ],
        "ansible_all_ipv6_addresses": [
            "fe80::b7d8:1d0e:aaef:8621",
            "fe80::2516:9a52:5095:b38b",
            "fe80::1c49:7bbe:c37d:b08d"
        ],
        "ansible_apparmor": {
            "status": "disabled"
        },
...

安装包

1. 安装包

# ansible -i hosts-basic-usage web -m yum -a "name=httpd state=present"

2. 验证安装

# ssh servera.example.com 'rpm -qa | grep httpd-[0-9]*'
httpd-tools-2.4.6-80.el7.x86_64
httpd-2.4.6-80.el7.x86_64

启动服务

1. 启动服务

# ansible -i hosts-basic-usage web -m service -a "name=httpd state=started"

2. 验证

# ssh servera.example.com 'systemctl status httpd'
● httpd.service - The Apache HTTP Server
   Loaded: loaded (/usr/lib/systemd/system/httpd.service; disabled; vendor preset: disabled)
   Active: active (running) since Tue 2018-12-11 22:20:59 CST; 36s ago
     Docs: man:httpd(8)
           man:apachectl(8)
 Main PID: 11593 (httpd)
   Status: "Total requests: 0; Current requests/sec: 0; Current traffic:   0 B/sec"
   CGroup: /system.slice/httpd.service
           ├─11593 /usr/sbin/httpd -DFOREGROUND
           ├─11595 /usr/sbin/httpd -DFOREGROUND
           ├─11596 /usr/sbin/httpd -DFOREGROUND
           ├─11597 /usr/sbin/httpd -DFOREGROUND
           ├─11598 /usr/sbin/httpd -DFOREGROUND
           └─11599 /usr/sbin/httpd -DFOREGROUND

Dec 11 22:20:56 servera.example.com systemd[1]: Starting The Apache HTTP Server...
Dec 11 22:20:57 servera.example.com httpd[11593]: AH00558: httpd: Could not reliably determine the server's fully qualified domain name, using servera.example.com. Set the 'ServerName' directive globally to suppress this message
Dec 11 22:20:59 servera.example.com systemd[1]: Started The Apache HTTP Server.

ansible-playbook

准备 playbook

创建 site.yml，添加如下内容

---
- hosts: web
  name: Install the web server and start it
  become: yes
  vars:
    httpd_packages:
      - httpd
      - mod_wsgi
    apache_test_message: This is a test message
    apache_max_keep_alive_requests: 115

  tasks:
    - name: Install the apache web server
      yum:
        name: ""
        state: present
      with_items: ""
      notify: restart apache service

    - name: Generate apache's configuration file from jinja2 template
      template:
        src: templates/httpd.conf.j2
        dest: /etc/httpd/conf/httpd.conf
      notify: restart apache service

    - name: Generate a basic homepage from jinja2 template
      template:
        src: templates/index.html.j2
        dest: /var/www/html/index.html

    - name: Start the apache web server
      service:
        name: httpd
        state: started
        enabled: yes

  handlers:
    - name: restart apache service
      service:
        name: httpd
        state: restarted
        enabled: yes

创建 Jinja2 模版

1. 创建 templates 目录

# mkdir templates

2. 创建 httpd.conf.j2 文件，添加如下内容

ServerRoot "/etc/httpd"
Listen 80
Include conf.modules.d/*.conf
User apache
Group apache
ServerAdmin root@localhost
<Directory />
    AllowOverride none
    Require all denied
</Directory>
DocumentRoot "/var/www/html"
<Directory "/var/www">
    AllowOverride None
    Require all granted
</Directory>
<Directory "/var/www/html">
    Options Indexes FollowSymLinks
    AllowOverride None
    Require all granted
</Directory>
<IfModule dir_module>
    DirectoryIndex index.html
</IfModule>
<Files ".ht*">
    Require all denied
</Files>
ErrorLog "logs/error_log"
MaxKeepAliveRequests
LogLevel warn
<IfModule log_config_module>
    LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\"" combined
    LogFormat "%h %l %u %t \"%r\" %>s %b" common
    <IfModule logio_module>
      LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\" %I %O" combinedio
    </IfModule>
    CustomLog "logs/access_log" combined
</IfModule>
<IfModule alias_module>
    ScriptAlias /cgi-bin/ "/var/www/cgi-bin/"
</IfModule>
<Directory "/var/www/cgi-bin">
    AllowOverride None
    Options None
    Require all granted
</Directory>
<IfModule mime_module>
    TypesConfig /etc/mime.types
    AddType application/x-compress .Z
    AddType application/x-gzip .gz .tgz
    AddType text/html .shtml
    AddOutputFilter INCLUDES .shtml
</IfModule>
AddDefaultCharset UTF-8
<IfModule mime_magic_module>
    MIMEMagicFile conf/magic
</IfModule>
EnableSendfile on
IncludeOptional conf.d/*.conf

3. 创建 index.html.j2 文件，添加如下内容

    <br>
Current Host:  <br>
Server list: <br>

4. 确保文件创建如下

templates/
├── httpd.conf.j2
└── index.html.j2

执行 Playbook

1. 执行 ansible-playbook

# ansible-playbook -i hosts-basic-usage site.yml

2. 测试 Web 服务

# curl servera.example.com
This is a test message RedHat 7.5  <br>
Current Host: servera <br>
Server list: <br>
servera.example.com <br>