Pillar is an interface for Salt designed to offer global values that can be distributed to all minions. Pillar data is managed in a similar way as the Salt State Tree.
Pillar was added to Salt in version 0.9.8
Note
Storing sensitive data
Unlike state tree, pillar data is only available for the targeted minion specified by the matcher type. This makes it useful for storing sensitive data specific to a particular minion.
The Salt Master server maintains a pillar_roots setup that matches the
structure of the file_roots used in the Salt file server. Like the
Salt file server the pillar_roots
option in the master config is based
on environments mapping to directories. The pillar data is then mapped to
minions based on matchers in a top file which is laid out in the same way
as the state top file. Salt pillars can use the same matcher types as the
standard top file.
The configuration for the pillar_roots
in the master config file
is identical in behavior and function as file_roots
:
pillar_roots:
base:
- /srv/pillar
This example configuration declares that the base environment will be located
in the /srv/pillar
directory. It must not be in a subdirectory of the
state tree.
The top file used matches the name of the top file used for States, and has the same structure:
/srv/pillar/top.sls
base:
'*':
- packages
In the above top file, it is declared that in the 'base' environment, the glob matching all minions will have the pillar data found in the 'packages' pillar available to it. Assuming the 'pillar_roots' value of '/srv/salt' taken from above, the 'packages' pillar would be located at '/srv/salt/packages.sls'.
Another example shows how to use other standard top matching types to deliver specific salt pillar data to minions with different properties.
Here is an example using the 'grains' matcher to target pillars to minions by their 'os' grain:
dev:
'os:Debian':
- match: grain
- servers
/srv/pillar/packages.sls
{% if grains['os'] == 'RedHat' %}
apache: httpd
git: git
{% elif grains['os'] == 'Debian' %}
apache: apache2
git: git-core
{% endif %}
company: Foo Industries
The above pillar sets two key/value pairs. If a minion is running RedHat, then the 'apache' key is set to 'httpd' and the 'git' key is set to the value of 'git'. If the minion is running Debian, those values are changed to 'apache2' and 'git-core' respctively. All minions that have this pillar targeting to them via a top file will have the key of 'company' with a value of 'Foo Industries'.
Consequently this data can be used from within modules, renderers, State SLS files, and more via the shared pillar dict:
apache:
pkg.installed:
- name: {{ pillar['apache'] }}
git:
pkg.installed:
- name: {{ pillar['git'] }}
Finally, the above states can utilize the values provided to them via Pillar. All pillar values targeted to a minion are available via the 'pillar' dictionary. As seen in the above example, Jinja substitution can then be utilized to access the keys and values in the Pillar dictionary.
Note that you cannot just list key/value-information in top.sls
. Instead,
target a minion to a pillar file and then list the keys and values in the
pillar. Here is an example top file that illustrates this point:
base:
'*':
- common_pillar
And the actual pillar file at '/srv/salt/common_pillar.sls':
foo: bar
boo: baz
The separate pillar files all share the same namespace. Given a top.sls
of:
base:
'*':
- packages
- services
a packages.sls
file of:
bind: bind9
and a services.sls
file of:
bind: named
Then a request for the bind
pillar will only return 'named'; the 'bind9'
value is not available. It is better to structure your pillar files with more
hierarchy. For example your package.sls
file could look like:
packages:
bind: bind9
With some care, the pillar namespace can merge content from multiple pillar files under a single key, so long as conflicts are avoided as described above.
For example, if the above example were modified as follows, the values are merged below a single key:
base:
'*':
- packages
- services
And a packages.sls
file like:
bind:
package-name: bind9
version: 9.9.5
And a services.sls
file like:
bind:
port: 53
listen-on: any
The resulting pillar will be as follows:
$ salt-call pillar.get bind
local:
----------
listen-on:
any
package-name:
bind9
port:
53
version:
9.9.5
Note
Remember: conflicting keys will be overwritten in a non-deterministic manner!
New in version 0.16.0.
Pillar SLS files may include other pillar files, similar to State files. Two syntaxes are available for this purpose. The simple form simply includes the additional pillar as if it were part of the same file:
include:
- users
The full include form allows two additional options -- passing default values to the templating engine for the included pillar file as well as an optional key under which to nest the results of the included pillar:
include:
- users:
defaults:
sudo: ['bob', 'paul']
key: users
With this form, the included file (users.sls) will be nested within the 'users' key of the compiled pillar. Additionally, the 'sudo' value will be available as a template variable to users.sls.
Once the pillar is set up the data can be viewed on the minion via the
pillar
module, the pillar module comes with two functions,
pillar.items
and and pillar.raw
. pillar.items
will return a freshly reloaded pillar and pillar.raw
will return the current pillar without a refresh:
salt '*' pillar.items
Note
Prior to version 0.16.2, this function is named pillar.data
. This
function name is still supported for backwards compatibility.
New in version 0.14.0.
The pillar.get
function works much in the same
way as the get
method in a python dict, but with an enhancement: nested
dict components can be extracted using a : delimiter.
If a structure like this is in pillar:
foo:
bar:
baz: qux
Extracting it from the raw pillar in an sls formula or file template is done this way:
{{ pillar['foo']['bar']['baz'] }}
Now, with the new pillar.get
function the data
can be safely gathered and a default can be set, allowing the template to fall
back if the value is not available:
{{ salt['pillar.get']('foo:bar:baz', 'qux') }}
This makes handling nested structures much easier.
Note
pillar.get()
vs salt['pillar.get']()
It should be noted that within templating, the pillar
variable is just
a dictionary. This means that calling pillar.get()
inside of a
template will just use the default dictionary .get()
function which
does not include the extra :
delimiter functionality. It must be
called using the above syntax (salt['pillar.get']('foo:bar:baz',
'qux')
) to get the salt function, instead of the default dictionary
behavior.
When pillar data is changed on the master the minions need to refresh the data
locally. This is done with the saltutil.refresh_pillar
function.
salt '*' saltutil.refresh_pillar
This function triggers the minion to asynchronously refresh the pillar and will
always return None
.
Pillar data can be used when targeting minions. This allows for ultimate control and flexibility when targeting minions.
salt -I 'somekey:specialvalue' test.ping
Like with Grains, it is possible to use globbing
as well as match nested values in Pillar, by adding colons for each level that
is being traversed. The below example would match minions with a pillar named
foo
, which is a dict containing a key bar
, with a value beginning with
baz
:
salt -I 'foo:bar:baz*' test.ping
Pillar data can be set at the command line like the following example:
salt '*' state.highstate pillar='{"cheese": "spam"}'
This will create a dict with a key of 'cheese' and a value of 'spam'. A list can be created like this:
salt '*' state.highstate pillar='["cheese", "milk", "bread"]'
For convenience the data stored in the master configuration file is made available in all minion's pillars. This makes global configuration of services and systems very easy but may not be desired if sensitive data is stored in the master configuration.
To disable the master config from being added to the pillar set pillar_opts
to False
:
pillar_opts: False