1. Modify the file and copy it to the host
1.1 Common file modules
| blockinfile | Add a text block to an existing file |
|---|---|
| copy | Copy files to managed host |
| fetch | Copy files from managed host to control node |
| file | Set file attributes |
| lineinfile | Make sure a specific line is in a file |
| stat | Retrieve file status information |
| synchronize | A packager for the rsync command |
| file | The module processes the file, and if it does not exist, it is created |
cat file.yml
---
- name: Test
hosts: webservers
tasks:
- name: Touch a file
file:
path: /root/file
owner: student
group: student
mode: 0640
state: touch
Modify file attributes
cat file.yml
---
- name: Test
hosts: webservers
tasks:
- name: Touch a file
file:
path: /root/file
owner: student
group: student
mode: 0640
state: touch
- name: Set SElinux
file:
path: /root/file
setype: samba_share_t
Permanent change
cat file.yml
- name: Test
hosts: webservers
tasks:
- name: Touch a file
file:
path: /root/file
owner: student
group: student
mode: 0640
state: touch
- name: Set SElinux
file:
path: /root/file
setype: samba_share_t
- name: Set SElinux
sefcontext:
target: /root/file
setype: samba_share_t
state: present
Copy and edit files
on managed hosts Delete files from managed hosts
- name: Delete file
file:
dest: /root/file
state: absent #absent 即删除
Check the file status on the managed host
Check the MD5 checksum of the file
- name: Verify the status
stat:
path: /root/file
checksum_algorithm: md5
register: result
-debug:
msg: "The checksum is {{ result.stat.checksum }}"
Run (add the above code to file.yml at the end)
TASK [debug] *******************************************************************
ok: [servera.lab.example.com] => {
"msg": "The checksum is d41d8cd98f00b204e9800998ecf8427e"
}
Synchronize files between control node and managed host
- name: synchronize file
synchronize:
src: file
dest: /root/file
Second, use jinja2 template to deploy custom files
Build a template to manage files more conveniently
{% EXPR%} #Expression or logic
{{EXPR}} #Finally output the expression or result to the user
{# COMMENT #} #Comment
2.1 Build jinja2 template
The jinja2 template is composed of multiple elements: data, variables, expressions
. The variables used in the template can be specified in the vars of the playbook
. All values in the template use variables, which will be replaced by the corresponding values of the managed host in the future. For
example: / etc / ssh / sshd_config file
Port 22 ==> Port {{ssh_port}}
PermitRootLogin yes ==> {{root_allowed}}
2.2 Deploying jinja2 template
tasks:
- name: template
template:
src: /root/j2-template.j2
dest: /root/dest-config-file.txt
Use loop
jinja2 Use the for statement to provide loop:
# 1.
{% For user in users%}
{{user}} #user variable will traverse users
{% endfor%}
# 2.
{% For myhost in groups ['myhosts'] %} #List all hosts in the myhosts group
{{myhosts}}
{% endfor%} #Use
conditional sentences
{% if finished%} #Only if this condition is true, will the value of the result variable be put into the file
{{result }}
{% endif%}
Jinja2 loops and conditions can only be used in templates, not in playbooks
2.3 Variable filters
{{output | to_json}} #Output in json format
{{output | to_yaml}}
{{output | from_json}} #Parse json format string
{{output | from_yaml}}
3. Management of large projects
3.1 Use wildcards to match multiple hosts
- hosts: '*'
- hosts: '*.example.com'
- hosts: '172.25.254.*'
3.2 Matching hosts or host groups by list
- hosts: www1.example.com,www2.example.com,172.25.254.250
- hosts: webservers,westos
You can also use wildcards and lists together
- hosts: webservers,&westos #即属于webserver 组，也属于westos 组
- hosts: westos,!servera.lab.example.com#匹配westos 组中所有主机，但是servera.lab.example.com 除外
- all,!servera.lab.example.com #所有主机除了servera.lab.example.com
4. Management Dynamic List
4.1 Writing a dynamic inventory program
Convert list in INI format to JSON format
ansible-inventory -i inventory --list
Using forks to configure parallel
ansible in ansible The maximum number of simultaneous connections is controlled by the forks parameter in the ansible configuration file
grep forks /etc/ansible/ansible.cfg
#forks = 5 #默认是5
ansible-config dump | grep -i forks
DEFAULT_FORKS(default) = 5
You can use the -f or --forks parameter on the command line to specify the number of parallels
V. Management of rolling updates
If the update occurs on the load balancing server, it will restart after the update is completed, which may cause all back-end web servers to stop serving. You can use the serial keyword to run in batches
---
- name: Rolling update
hosts: webservers
serial: 2
tasks:
- name: Install apache
yum:
name: httpd
state: latest
notify: restart apache
handlers:
- name: restart apache
service:
name: httpd
state: restarted
The serial parameter also has an advantage: if there is a problem during the update, then the problem in the first two is that the playbook will stop running, and the subsequent servers will not be executed, so the high availability of the service is also guaranteed
Six, include and import files
Large playbooks are more complicated to manage and can be managed in a modular way.
Two methods: include, import
Import playbook
example 1:
- name: configure webserver
import_playbook: web.yml
Example 2:
- name: Play 1
hosts: localhost
tasks:
- debug:
msg: Play1
- name: Import Playbook
import_playbook: play2.yml
Import and include a playbook of
tasks
cat tasks.yml
- name: Install apache
yum:
name: httpd
state: latest
- name: Start Apache
service:
name: httpd
state: started
Import task
---
- name: Install web
hosts: webservers
tasks:
- import_tasks: tasks.yml
When importing, conditional statements such as when are applied to each task of the import; the loop cannot be applied to the imported
task.
---
- name: Install web
hosts: webservers
tasks:
- include_tasks: tasks.yml
External play and tasks defined variables, improve reusability
a package installation tasks and configuration of the boot
---
- name: Install the {{ packages }}
yum:
name: "{{ packages }}"
state: latest
- name: Start the {{ service }}
service:
name: "{{ service }}"
enabled: true
state: started
Can be used for import
tasks:
- name: Import task
import_tasks: task.yml
vars:
package: httpd
service: httpd
Comprehensive experiment of managing large projects
cat ansible.cfg
[defaults]
inventory = ./inventory
cat inventory
servera.lab.example.com
serverb.lab.example.com
serverc.lab.example.com
ansible server*.lab.example.com --list-hosts
Same module: installation package
cat install_and_enabled.yml
---
- name: Install {{ packages }}
yum:
name: "{{ packages }}"
state: latest
- name: Enable and start {{ service }}
service:
name: "{{ service }}"
enabled: true
state: started
Apache configuration
cat web_tasks.yml
---
- name: Install and start httpd
import_tasks: install_and_enabled.yml
vars:
packages: httpd
service: httpd
- name: Configure apache
copy:
src: files/example.conf
dest: /etc/httpd/conf.d/example.conf
owner: root
group: root
mode: 0644
notify:
- restart httpd
firewall configuration
cat firewall_tasks.yml
---
- name: Install and start firewalld
import_tasks: install_and_enabled.yml
vars:
packages: firewalld
service: firewalld
- name: Firewall permit apache
firewalld:
service: http
immediate: true
permanent: true
state: enabled
主playbook
cat playbook.yml
---
- name: Install and Configure web service
hosts: server*.lab.example.com
serial: 2
tasks:
- name: Import web_tasks.yml
import_tasks: tasks/web_tasks.yml
- name: Import the firewall_tasks.yml
import_tasks: tasks/firewall_tasks.yml
handlers:
- name: restart httpd
service:
name: httpd
state: restarted
