1. Loop
Loop iteration task
1. Simple loop
loop: ##Assignment list
- value1
- value2
-...
{<!-- -->{item}} ##Iteration variable name
#Example#
---
- name: create file
hosts: 172.25.0.254
tasks:
- name: file module
file:
name: /mnt/{<!-- -->{item}}
state: present
loop:
- westos_file1
- westos_file2
2. Circular hash or dictionary list
---
- name: create file
hosts: 172.25.0.254
tasks:
- name: file module
service:
name: "{<!-- -->{ item.name}}"
state: "{<!-- -->{ item.state }}"
loop:
- name: httpd
state: started
- name: vsftpd
state: stopped
2. Conditions
when:
- Condition 1
- Condition 2
#Conditional judgment#
= value == "string",value == number
< value < number
> value > number
<= value <= number
>= value >= number
!= value != number
is defined value value is defined variable exists
is not defined value is not defined The variable does not exist
in value is in value variable is
not in value is not in value variable is not
bool variable is true value value is true
bool variable false not value value is false
value in value2 value is in the value2 list
#Multiple conditions combination# when： Condition 1 and Condition 2 - Condition 1 - Condition 2 when: Condition 1 or Condition 2 when: > Condition 1 or Condition 2
true and false
3. Trigger
notify: The trigger triggers handlers when encountering changes. handlers: Actions executed after the trigger is fired
#Example#
---
- name: create virtualhost for web server
hosts: 172.25.0.254
vars_files:
./vhost_list.yml
tasks:
- name: create document
file:
path: "{<!-- -->{web2.document}}"
state: directory
- name: create vhost.conf
copy:
dest: /etc/httpd/conf.d/vhost.conf
content:
"<VirtualHost *:{<!-- -->{web1.port}}>\\
\tServerName {<!-- -->{web1.name}}\\
\tDocumentRoot
{<!-- -->{web1.document}}\\
\tCustomLog logs/{<!-- -->{web1.name}}.log combined\\
</VirtualHost>\\
\ \
<VirtualHost *:
{<!-- -->{web2.port}}>\\
\tServerName {<!-- -->{web2.name}}\\
\tDocumentRoot {<!-- -->{ web2.document}}\\
\tCustomLog logs/
{<!-- -->{web2.name}}.log combined\\
</VirtualHost>"
notify: notify
restart apache
handlers:
- name: restart apache
service:
name: httpd
state: restarted
4. Handle failed tasks
1.ignore_errors
#effect:
Play will terminate when it encounters a task failure
ignore_errors: yes will ignore task failures and allow the following tasks to continue running
#Example#
- name: check file play
hosts: all
tasks:
- name: check file
shell:
test -e /mnt/file
ignore_errors: yes
register: check_state
- name: show message
debug:
msg: hello world
2.force_handlers
#effect:
#When the task fails and the play is terminated, the trigger process will also be called.
#example
---
- name: apache change port
hosts: 172.25.0.254
force_handlers: yes
vars:
http_port: 80
tasks:
- name: configure apache conf file
lineinfile:
path: /etc/httpd/conf/httpd.conf
regexp: "^Listen"
line: "Listen {<!-- -->{ http_port }}"
notify: restart apache
- name: install error
dnf:
name: westos
state: latest
handlers:
- name: restart apache
service:
name: httpd
state: restarted
enabled: yes
3.changed_when
#effect:
#Control when a task reports that it has made changes; force changes: true, force no changes: false
---
- name: apache change port
hosts: 172.25.0.254
force_handlers: yes
vars:
http_port: 8080
tasks:
- name: configure apache conf file
lineinfile:
path: /etc/httpd/conf/httpd.conf
regexp: "^Listen"
line: "Listen {<!-- -->{ http_port }}"
changed_when: true
notify: restart apache
handlers:
- name: restart apache
service:
name: httpd
state: restarted
enabled: yes
4.failed_when
#Force the task to fail when the conditions are met
#Force a play to fail
---
- name: test
hosts: 172.25.0.254
tasks:
- name: shell
shell: echo hello
register: westos
failed_when: "'hello' in westos.stdout"
5.block
block: ##Define the tasks to be run
rescue: ##Define the task to be run when a failed task appears in the block sentence
##block runs successfully, then rescue does not run.
always: ##Define the task that will eventually run independently
5. Practice
The requirements for creating playbook ~/westos.yml are as follows: Create a device named /dev/vdb1 with a size of 1500M If /dev/vdb does not exist please enter: /dev/vdb is not present If the size of /dev/vdb is less than 1.5G, please output: /dev/vdb is less then 1.5G And create 800M size /dev/vdb1 This device is mounted on /westos
- name: test fdisk
hosts: all
tasks:
- name: check sdb
debug:
msg: /dev/sdb is not present
when: ansible_facts['devices']['sdb'] is not defined
- name: create /dev/sdb1
block:
- name: check size
parted:
device: /dev/sdb
number: 1
state: present
part_end: 1.5GiB
when: ansible_facts['devices']['sdb'] is defined
- name: show size is not enough 1.5G
debug:
msg: /dev/sdb is not enough 1.5G
rescue:
- name: create /dev/sdb1
parted:
device: /dev/sdb
number: 1
state: present
part_end: 800MiB
notify: notify
- set filesystem
- mount /dev/sdb1
when: ansible_facts['devices']['sdb'] is defined
always:
- name: create mount point
file:
path: /westos
state: directory
handlers:
- name: set filesystem
filesystem:
fstype: ext4
dev: /dev/sdb1
- name: mount /dev/sdb1
mount:
path: /westos/
src: /dev/sdb1
fstype: ext4
state: mounted
