mirror of
https://github.com/ansible/awx.git
synced 2024-11-01 16:51:11 +03:00
43 lines
2.2 KiB
Markdown
43 lines
2.2 KiB
Markdown
# AWX as an Ansible Fact Cache
|
|
AWX can store and retrieve per-host facts via an Ansible Fact Cache Plugin.
|
|
This behavior is configurable on a per-job-template basis. When enabled, AWX
|
|
will serve fact requests for all Hosts in an Inventory related to the Job
|
|
running. This allows users to use Job Templates with `--limit` while still
|
|
having access to the entire Inventory of Host facts.
|
|
|
|
## AWX Fact Cache Implementation Details
|
|
### AWX Injection
|
|
In order to understand the behavior of AWX as a fact cache you will need to
|
|
understand how fact caching is achieved in AWX. When a Job launches with
|
|
`use_fact_cache=True`, AWX will write all `ansible_facts` associated with
|
|
each Host in the associated Inventory as JSON files on the local file system
|
|
(one JSON file per host). Jobs invoked with `use_fact_cache=False` will not
|
|
write `ansible_facts` files.
|
|
|
|
### Ansible plugin usage
|
|
When `use_fact_cache=True`, Ansible will be configured to use the `jsonfile`
|
|
cache plugin. Any `get()` call to the fact cache interface in Ansible will
|
|
result in a JSON file lookup for the host-specific set of facts. Any `set()`
|
|
call to the fact cache will result in a JSON file being written to the local
|
|
file system.
|
|
|
|
### AWX Cache to DB
|
|
When a Job with `use_fact_cache=True` finishes running, AWX will look at all
|
|
of the local JSON files that represent the fact data. Any records with file
|
|
modification times that have increased (because Ansible updated the file via
|
|
`cache.set()`) will result in the latest value being saved to the database. On
|
|
subsequent playbook runs, AWX will _only_ inject cached facts that are _newer_
|
|
than `settings.ANSIBLE_FACT_CACHE_TIMEOUT` seconds.
|
|
|
|
## AWX Fact Logging
|
|
New and changed facts will be logged via AWX's logging facility. Specifically,
|
|
to the `system_tracking` namespace or logger. The logging payload will include
|
|
the fields: `host_name`, `inventory_id`, and `ansible_facts`. Where
|
|
`ansible_facts` is a dictionary of all ansible facts for `host_name` in AWX
|
|
Inventory `inventory_id`.
|
|
|
|
## Integration Testing
|
|
* ensure `clear_facts` set's `hosts/<id>/ansible_facts` to `{}`
|
|
* ensure that `gather_facts: False` does NOT result in clearing existing facts
|
|
* ensure that the when a host fact timeout is reached, that the facts are not used from the cache
|