[student@workstation netfilters]$ cat ./tasks/main.yml
# Complete each task by setting the fact as the expected value.
# Replace ellipsis by the appropriate filter usage.
# All task but the last one should be using the 'ipaddr' filter.
# Use the lookup filter with the `dig` command for the last task
# Tasks make use of th gathered fact 'default_ipv4', and its keys 'address', 'network' and 'netmask'
- name: Task 1- Verify the 'ansible_default_ipv4.addresss' provided address is correctly formatted.
  set_fact:
    server_address: "{{ ansible_facts.default_ipv4.address | ipaddr }}"
- name: Task 2- Check 'server_address' value
  assert:
    that: "server_address == ansible_facts.default_ipv4.address"
    fail_msg: "'server_address' must be {{ ansible_facts.default_ipv4.address }}, but is {{ server_address }}"
- name: Task 3- Obtain the DNS name associated to the server IP address (reverse DNS)
  set_fact:
    address_dns: "{{ server_address | ipaddr('revdns') }}"
- name: Task 4- Check 'address_dns' value
  assert:
    that: "address_dns == '10.250.25.172.in-addr.arpa.'"
    fail_msg: "'address_dns' must be '10.250.25.172.in-addr.arpa.', but is {{ address_dns }}"
- name: Task 5- Obtain server's network/netmask
  set_fact:
    net_mask: "{{ ansible_facts.default_ipv4.network }}/{{ ansible_facts.default_ipv4.netmask }}"
- name: Task 6- Check 'net_mask' value
  assert:
    that: "net_mask == '172.25.250.0/255.255.255.0'"
    fail_msg: "'net_mask' must be '172.25.250.0/255.255.255.0', but is {{ net_mask }}"
- name: Task 7- Transform the network/netmask to the CIDR format
  set_fact:
    cidr: "{{ net_mask | ipaddr('net') }}"
- name: Task 8- Check 'cidr' value
  assert:
    that: "cidr == '172.25.250.0/24'"
    fail_msg: "'cidr' must be '172.25.250.0/24', but is {{ cidr }}"
- name: Task 9- Verify the server address actualy belong to the network/mask
  set_fact:
    address_in_range: "{{ server_address | ipaddr(net_mask) }}"
- name: Task 10- Check 'address_in_range' value
  assert:
    that: "address_in_range == server_address"
    fail_msg: "'address_in_range' must be {{ server_address }}, but is {{ address_in_range }}"
- name: Task 11- Obtain the broadcast address associated to the CIDR
  set_fact:
    broadcast: "{{ cidr | ipaddr('broadcast') }}"
- name: Task 12- Check 'broadcast' value
  assert:
    that: "broadcast == '172.25.250.255'"
    fail_msg: "'broadcast' must be '172.25.250.255', but is {{ broadcast }}"
- name: Task 13- DIG for the MX record of the domain 'example.com'
  set_fact:
    dig_record: "{{ lookup( 'dig', 'example.com.', 'qtype=MX') }}"
- name: Task 14- Check 'dig_record' value
  assert:
    that: "dig_record == '10 classroom.example.com.'"
    fail_msg: "'dig_record' must be '10 classroom.example.com.', but is '{{ dig_record }}'"
[student@workstation data-netfilters]$ ansible-playbook  site.yml
PLAY [Tasks for netfilter guided exercise] *****************************************************************************
TASK [Gathering Facts] *************************************************************************************************
ok: [servera.lab.example.com]
TASK [netfilters : Task 1- Verify the 'ansible_default_ipv4.addresss' provided address is correctly formatted.] ********
ok: [servera.lab.example.com]
TASK [netfilters : Task 2- Check 'server_address' value] ***************************************************************
ok: [servera.lab.example.com] => {
    "changed": false,
    "msg": "All assertions passed"
TASK [netfilters : Task 3- Obtain the DNS name associated to the server IP address (reverse DNS)] **********************
ok: [servera.lab.example.com]
TASK [netfilters : Task 4- Check 'address_dns' value] ******************************************************************
ok: [servera.lab.example.com] => {
    "changed": false,
    "msg": "All assertions passed"
TASK [netfilters : Task 5- Obtain server's network/netmask] ************************************************************
ok: [servera.lab.example.com]
TASK [netfilters : Task 6- Check 'net_mask' value] *********************************************************************
ok: [servera.lab.example.com] => {
    "changed": false,
    "msg": "All assertions passed"
TASK [netfilters : Task 7- Transform the network/netmask to the CIDR format] *******************************************
ok: [servera.lab.example.com]
TASK [netfilters : Task 8- Check 'cidr' value] *************************************************************************
ok: [servera.lab.example.com] => {
    "changed": false,
    "msg": "All assertions passed"
TASK [netfilters : Task 9- Verify the server address actualy belong to the network/mask] *******************************
ok: [servera.lab.example.com]
TASK [netfilters : Task 10- Check 'address_in_range' value] ************************************************************
ok: [servera.lab.example.com] => {
    "changed": false,
    "msg": "All assertions passed"
TASK [netfilters : Task 11- Obtain the broadcast address associated to the CIDR] ***************************************
ok: [servera.lab.example.com]
TASK [netfilters : Task 12- Check 'broadcast' value] *******************************************************************
ok: [servera.lab.example.com] => {
    "changed": false,
    "msg": "All assertions passed"
TASK [netfilters : Task 13- DIG for the MX record of the domain 'example.com'] *****************************************
ok: [servera.lab.example.com]
TASK [netfilters : Task 14- Check 'dig_record' value] ******************************************************************
ok: [servera.lab.example.com] => {
    "changed": false,
    "msg": "All assertions passed"
PLAY RECAP *************************************************************************************************************
servera.lab.example.com    : ok=15   changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
[student@workstation data-netfilters]$ cat site.yml
- name: Tasks for netfilter guided exercise
  hosts: servera.lab.example.com
  roles:
    - role: netfilters
[student@workstation data-netfilters]$
《DO447》
                    使用过滤器检查、验证和操作包含网络信息的变量理解不足小伙伴帮忙指正傍晚时分，你坐在屋檐下，看着天慢慢地黑下去，心里寂寞而凄凉，感到自己的生命被剥夺了。当时我是个年轻人，但我害怕这样生活下去，衰老下去。在我看来，这是比死亡更可怕的事。--------王小波。
每个playbook中的play 都必须包含 hosts 和 tasks两个项
使用“-”作为列表项,一个“-”代表一个任务，某项是一个动作，一个对象，或一个实体时，都加‘-’
zhangsan
wangwu
[zhangsan,lisi,wangwu]
“zhangsan”,
“lisi”,
				
现在我有一个需求，我想要将获取到的变量的值中的所有字母都变成大写，如果想要在playbook中实现这个需求，我该怎么办呢？我可以借助一个叫做"过滤器"的东西，帮助我完成刚才的需求，"过滤器（filters）"可以帮助我们对数据进行处理，这样解释可能不够直观，不如这样，我们先来看一个过滤器的小例子，然后结合示例解释过滤器是个什么东西，示例如下：
[root@server4 ~]# vim gl1.y...
安装wgetyum -y install wget
	下载 python 文件wget https://www.python.org/ftp/python/3.7.0/Python-3.7.0.tgz （离线安装需提前准备压缩包）
	解压文件tar zxvf Python-3.7.0.tgz
	切换目录cd Python-3.7.0
编译并安装
编译./configure --prefix=/usr/local...
				
roles用于层次性、结构化地组织playbook。roles能够根据层次型结构自动装载变量文件、tasks以及handlers等。要使用roles只需要在playbook中使用include指令引入即可。
简单来讲，roles就是通过分别将变量、文件、任务、模板及处理器放置于单独的目录中，并可以便捷的include它们的一种机制。roles一般用于基于主机构建服务的场景中，但也可以是用于构建守护进程等场景中。主要使用场景代码复用度较高的情况下。假如我们现在有3个被管理主机，第一个要配置成httpd，第二个
				
在Ansible playbook中，可以使用错误处理机制来处理错误。以下是一些常见的错误处理技巧：
1. 忽略错误：可以在任务中使用ignore_errors选项来忽略错误。这将使Ansible在任务失败时不会停止执行。但需要注意的是，忽略错误可能会导致任务执行不完整，因此需要谨慎使用。
2. 检查错误：可以在任务中使用register选项将任务的输出保存到变量中，并使用failed_when选项检查任务是否失败。如果任务失败，可以使用fail模块输出错误消息并停止执行。
3. 处理错误：可以在任务中使用block和rescue块来处理错误。在block块中执行任务，如果任务失败，则跳转到rescue块中执行指定的任务。在rescue块中可以使用notify选项触发handler来处理错误。
4. 自定义错误处理：可以在playbook中定义handler来处理特定的错误。当任务失败时，可以使用notify选项触发handler执行相应的任务。
总之，Ansible提供了多种方式来处理错误，可以根据具体情况选择合适的方法来处理错误。