Documentation

set_fact – Set host facts from a task

Synopsis

  • This module allows setting new variables.
  • Variables are set on a host-by-host basis just like facts discovered by the setup module.
  • These variables will be available to subsequent plays during an ansible-playbook run.
  • Set cacheable to yes to save variables across executions using a fact cache. Variables created with set_fact have different precedence depending on whether they are or are not cached.
  • Per the standard Ansible variable precedence rules, many other types of variables have a higher priority, so this value may be overridden.
  • This module is also supported for Windows targets.

Parameters

Parameter Choices/Defaults Comments
cacheable
boolean
added in 2.4
    Choices:
  • no ←
  • yes
This boolean converts the variable into an actual 'fact' which will also be added to the fact cache, if fact caching is enabled.
Normally this module creates 'host level variables' and has much higher precedence, this option changes the nature and precedence (by 7 steps) of the variable created. https://docs.ansible.com/ansible/latest/user_guide/playbooks_variables.html#variable-precedence-where-should-i-put-a-variable
This actually creates 2 copies of the variable, a normal 'set_fact' host variable with high precedence and a lower 'ansible_fact' one that is available for persistance via the facts cache plugin. This creates a possibly confusing interaction with meta: clear_facts as it will remove the 'ansible_fact' but not the host variable.
key_value
- / required
The set_fact module takes key=value pairs as variables to set in the playbook scope. Or alternatively, accepts complex arguments using the args: statement.

Notes

Note

  • The var=value notation can only create strings or booleans. If you want to create lists/arrays or dictionary/hashes use var: [val1, val2].
  • Since ‘cacheable’ is now a module param, ‘cacheable’ is no longer a valid fact name as of Ansible 2.4.
  • This module is also supported for Windows targets.

See Also

See also

include_vars – Load variables from files, dynamically within a task
The official documentation on the include_vars module.
Variable precedence: Where should I put a variable?
More information related to variable precedence and which type of variable wins over others.

Examples

# Example setting host facts using key=value pairs, note that this always creates strings or booleans
- set_fact: one_fact="something" other_fact="{{ local_var }}"

# Example setting host facts using complex arguments
- set_fact:
     one_fact: something
     other_fact: "{{ local_var * 2 }}"
     another_fact: "{{ some_registered_var.results | map(attribute='ansible_facts.some_fact') | list }}"

# Example setting facts so that they will be persisted in the fact cache
- set_fact:
    one_fact: something
    other_fact: "{{ local_var * 2 }}"
    cacheable: yes

# As of Ansible 1.8, Ansible will convert boolean strings ('true', 'false', 'yes', 'no')
# to proper boolean values when using the key=value syntax, however it is still
# recommended that booleans be set using the complex argument style:
- set_fact:
    one_fact: yes
    other_fact: no

Status

Red Hat Support

More information about Red Hat’s support of this module is available from this Red Hat Knowledge Base article.

Authors

  • Dag Wieers (@dagwieers)

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