11.2. Event Driven Ansible - Events and Facts
In this lab we will have a closer look at events and facts.
Task 1
- Copy the rulebook from Lab 11.2 Task 3 to a new one with the name
debug_event_rulebook.yml. - Substitute the
run_playbook action with a debug action. - That debug action should print out all information from the event.
- Stop the httpd service on node1.
- Run the rulebook in verbose mode. The debug action should show all information about the event.
Solution Task 1
1
| cat debug_event_rulebook.yml
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
| ---
- name: show event json if site down
hosts: web
sources:
- name: check webserver
ansible.eda.url_check:
urls:
- http://<ip-of-node1>:80/
- http://<ip-of-node2>:80/
delay: 8
rules:
- name: check if site down and debug
condition: event.url_check.status == "down"
action:
debug:
var: event
|
1
| ansible node1 -i inventory/hosts -b -m service -a "name=httpd state=stopped"
|
1
| ansible-rulebook --rulebook debug_event_rulebook.yml -i inventory/hosts -vv
|
1
2
3
4
5
6
| ...
2023-06-26 15:04:55,381 - ansible_rulebook.rule_set_runner - INFO - call_action debug
2023-06-26 15:04:55,381 - ansible_rulebook.rule_set_runner - INFO - substitute_variables [{'var': 'event'}] [{'event': {'url_check': {'error_msg': "Cannot connect to host 5.102.146.223:80 ssl:default [Connect call failed ('5.102.146.223', 80)]", 'url': 'http://5.102.146.223/', 'status': 'down'}, 'meta': {'received_at': '2023-06-26T13:04:55.379428Z', 'source': {'name': 'check webserver', 'type': 'ansible.eda.url_check'}, 'uuid': '6710f9a8-c489-4699-a804-8e796855e290'}}}]
2023-06-26 15:04:55,381 - ansible_rulebook.rule_set_runner - INFO - action args: {'var': 'event'}
{'url_check': {'error_msg': "Cannot connect to host 5.102.146.223:80 ssl:default [Connect call failed ('5.102.146.223', 80)]", 'url': 'http://5.102.146.223/', 'status': 'down'}, 'meta': {'received_at': '2023-06-26T13:04:55.379428Z', 'source': {'name': 'check webserver', 'type': 'ansible.eda.url_check'}, 'uuid': '6710f9a8-c489-4699-a804-8e796855e290'}}
...
|
Task 2
- Rewrite the rulebook
debug_event_rulebook.yml: - Use a
run_playbook action to start a playbook named sos.yml - The playbook
sos.yml should create an unattended sos report labeled with the fully qualified collection name of the source plugin used. Be sure to install the appropriate packages so that the sos report can be created. - The name of the source plugin should be taken from the json output as a variable.
- The creation of the sos report takes quite some time.
- Ensure that the condition is throttled to run the action once within 5 minutes at most.
- The delay of the source check should stay at 8 seconds.
- Run the rulebook
debug_event_rulebook.yml and ensure the sos reports on the webservers have the needed label.
Note
There are good onlinetools to convert
one-line json to multiline json as well as
json to yaml converters. Note: The json copied from the output has sometimes single quotes, RFC 8259 demands double quotes. Be sure that your converter fixes this as well. These converters can come in handy for easier reading of the output.
Solution Task 2
See the documentation on how to throttle event storms.
1
| cat debug_event_rulebook.yml
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
| ---
- name: run sos playbook if site down
hosts: web
sources:
- name: check webserver
ansible.eda.url_check:
urls:
- http://<ip-of-node1>:80/
- http://<ip-of-node2>:80/
delay: 8
rules:
- name: check if site down and rebuild
condition: event.url_check.status == "down"
throttle:
once_within: 5 minutes
group_by_attributes:
- event.meta.source.type
action:
run_playbook:
name: sos.yml
|
1
2
3
4
5
6
7
8
9
10
11
12
13
| ---
- hosts: web
become: true
tasks:
- name: install sos package
ansible.builtin.dnf:
name:
- sos
state: installed
- name: create a sos report unattended containing no sensitive information
ansible.builtin.command: |
"sos report --clean --batch --label {{ ansible_eda.event.meta.source.type }}"
|
1
| ansible-rulebook --rulebook debug_event_rulebook.yml -i inventory/hosts -vv
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
| ...
2023-06-28 11:15:53,766 - ansible_rulebook.builtin - INFO - ruleset: show event \
json if site down, rule: check if site down and rebuild
2023-06-28 11:15:53,766 - ansible_rulebook.builtin - INFO - Calling Ansible runner
PLAY [web] *********************************************************************
TASK [Gathering Facts] *********************************************************
ok: [node1]
TASK [install sos package] *****************************************************
ok: [node1]
TASK [create a sos report unattended containing no sensitive information] ******
changed: [node1]
...
PLAY RECAP *********************************************************************
node1 : ok=3 changed=1 unreachable=0 failed=0
skipped=0 rescued=0 ignored=0
2023-06-28 11:17:59,741 - ansible_rulebook.builtin - INFO - Ansible Runner \
Queue task cancelled
2023-06-28 11:17:59,742 - ansible_rulebook.builtin - INFO - Playbook rc: 0, \
status: successful
...
|
All done?