# Requisites and Other Global State Arguments

## Requisites

The Salt requisite system is used to create relationships between states. This provides a method to easily define inter-dependencies between states. These dependencies are expressed by declaring the relationships using state names and IDs or names. The generalized form of a requisite target is `<state name>: <ID or name>`. The specific form is defined as a Requisite Reference.

A common use-case for requisites is ensuring a package has been installed before trying to ensure the service is running. In the following example, Salt will ensure nginx has been installed before trying to manage the service. If the package could not be installed, Salt will not try to manage the service.

    nginx:
      pkg.installed:
        - name: nginx-light
      service.running:
        - enable: True
        - require:
          - pkg: nginx

Without the requisite defined, salt would attempt to install the package and then attempt to manage the service even if the installation failed.

These requisites always form dependencies in a predictable single direction. Each requisite has an alternate <requisite>_in form that can be used to establish a "reverse" dependency--useful in for loops.

In the end, a single dependency map is created and everything is executed in a finite and predictable order.

### Requisite matching

Requisites typically need two pieces of information for matching:

- The state module name (e.g. `pkg` or `service`)

- The state identifier (e.g. `nginx` or `/etc/nginx/nginx.conf`)

    nginx:
      pkg.installed: []
      file.managed:
        - name: /etc/nginx/nginx.conf
      service.running:
        - require:
          - pkg: nginx
          - file: /etc/nginx/nginx.conf

#### Glob matching in requisites

New in version 0.9.8.

Glob matching is supported in requisites. This is mostly useful for file changes. In the example below, a change in `/etc/apache2/httpd.conf` or `/etc/apache2/sites-available/default.conf` will reload/restart the service:

    apache2:
      service.running:
        - watch:
          - file: /etc/apache2/*

### Omitting state module in requisites

New in version 2016.3.0.

In version 2016.3.0, the state module name was made optional. If the state module is omitted, all states matching the ID will be required, regardless of which module they are using.

    - require:
      - vim

#### State target matching

In order to understand how state targets are matched, it is helpful to know how the state compiler is working. Consider the following example:

    Deploy server package:
      file.managed:
        - name: /usr/local/share/myapp.tar.xz
        - source: salt://myapp.tar.xz

    Extract server package:
      archive.extracted:
        - name: /usr/local/share/myapp
        - source: /usr/local/share/myapp.tar.xz
        - archive_format: tar
        - onchanges:
          - file: Deploy server package

The first formula is converted to a dictionary which looks as follows (represented as YAML, some properties omitted for simplicity) as High Data:

    Deploy server package:
      file:
        - managed
        - name: /usr/local/share/myapp.tar.xz
        - source: salt://myapp.tar.xz

The `file.managed` format used in the formula is essentially syntactic sugar: at the end, the target is `file`, which is used in the `Extract server package` state above.

#### Identifier matching

Requisites match on both the ID Declaration and the `name` parameter. This means that, in the "Deploy server package" example above, a `require` requisite would match with `Deploy server package` or `/usr/local/share/myapp.tar.xz`, so either of the following versions for "Extract server package" is correct:

    # (Archive arguments omitted for simplicity)

    # Match by ID declaration
    Extract server package:
      archive.extracted:
        - onchanges:
          - file: Deploy server package

    # Match by name parameter
    Extract server package:
      archive.extracted:
        - onchanges:
          - file: /usr/local/share/myapp.tar.xz

#### Omitting state module in requisites

New in version 2016.3.0.

In version 2016.3.0, the state module name was made optional. If the state module is omitted, all states matching the ID will be required, regardless of which module they are using.

    - require:
      - vim

### Requisites Types

All requisite types have a corresponding <requisite>_in form:

- require: Requires that a list of target states succeed before execution

- onchanges: Execute if any target states succeed with changes

- watch: Similar to `onchanges`; modifies state behavior using `mod_watch`

- listen: Similar to `onchanges`; delays execution to end of state run using `mod_watch`

- prereq: Execute prior to target state if target state expects to produce changes

- onfail: Execute only if a target state fails

- use: Copy arguments from another state

Several requisite types have a corresponding requisite_any form:

- `require_any`

- `watch_any`

- `onchanges_any`

- `onfail_any`

Lastly, onfail has one special `onfail_all` form to account for when AND logic is desired instead of the default OR logic of onfail/onfail_any (which are equivalent).

All requisites define specific relationships and always work with the dependency logic defined above.

#### require

The use of `require` builds a dependency that prevents a state from executing until all required states execute successfully. If any required state fails, then the state will fail due to requisites.

In the following example, the `service` state will not be checked unless both `file` states execute without failure.

    nginx:
      service.running:
        - require:
          - file: /etc/nginx/nginx.conf
          - file: /etc/nginx/conf.d/ssl.conf

##### Require SLS File

As of Salt 0.16.0, it is possible to require an entire sls file. Do this by first including the sls file and then setting a state to `require` the included sls file:

    include:
      - foo

    bar:
      pkg.installed:
        - require:
          - sls: foo

This will add a `require` to all of the state declarations found in the given sls file. This means that `bar` will `require` every state within `foo`. This makes it very easy to batch large groups of states easily in any requisite statement.

#### onchanges

New in version 2014.7.0.

The `onchanges` requisite makes a state only apply if the required states generate changes, and if the watched state's "result" is `True` (does not fail). This can be a useful way to execute a post hook after changing aspects of a system.

If a state has multiple `onchanges` requisites then the state will trigger if any of the watched states changes.

    myservice:
      file.managed:
        - name: /etc/myservice/myservice.conf
        - source: salt://myservice/files/myservice.conf
      cmd.run:
        - name: /usr/local/sbin/run-build
        - onchanges:
          - file: /etc/myservice/myservice.conf

In the example above, `cmd.run` will run only if there are changes in the `file.managed` state.

An easy mistake to make is using `onchanges_in` when `onchanges` is the correct choice, as seen in this next example.

    myservice:
      file.managed:
        - name: /etc/myservice/myservice.conf
        - source: salt://myservice/files/myservice.conf
      cmd.run:
        - name: /usr/local/sbin/run-build
        - onchanges_in:  # <-- broken logic
          - file: /etc/myservice/myservice.conf

This will set up a requisite relationship in which the `cmd.run` state always executes, and the `file.managed` state only executes if the `cmd.run` state has changes (which it always will, since the `cmd.run` state includes the command results as changes).

It may semantically seem like the `cmd.run` state should only run when there are changes in the file state, but remember that requisite relationships involve one state watching another state, and a requisite_in does the opposite: it forces the specified state to watch the state with the `requisite_in`.

Note

An `onchanges` requisite has no effect on SLS requisites (monitoring for changes in an included SLS). Only the individual state IDs from an included SLS can be monitored.

#### watch

A `watch` requisite is used to add additional behavior when there are changes in other states. This is done using the `mod_watch` function available from the execution module and will execute any time a watched state changes.

Note

If a state should only execute when another state has changes, and otherwise do nothing, the `onchanges` requisite should be used instead of `watch`. `watch` is designed to add additional behavior when there are changes, but otherwise the state executes normally.

Note

A `watch` requisite has no effect on SLS requisites (watching for changes in an included SLS). Only the individual state IDs from an included SLS can be watched.

A good example of using `watch` is with a `service.running` state. When a service watches a state, then the service is reloaded/restarted when the watched state changes, in addition to Salt ensuring that the service is running.

    ntpd:
      service.running:
        - watch:
          - file: /etc/ntp.conf
      file.managed:
        - name: /etc/ntp.conf
        - source: salt://ntp/files/ntp.conf

Another useful example of `watch` is using salt to ensure a configuration file is present and in a correct state, ensure the service is running, and trigger `service nginx reload` instead of `service nginx restart` in order to avoid dropping any connections.

    nginx:
      service.running:
        - reload: True
        - watch:
          - file: nginx
      file.managed:
        - name: /etc/nginx/conf.d/tls-settings.conf
        - source: salt://nginx/files/tls-settings.conf

Note

Not all state modules contain `mod_watch`. If `mod_watch` is absent from the watching state module, the `watch` requisite behaves exactly like a `require` requisite.

The state containing the `watch` requisite is defined as the watching state. The state specified in the `watch` statement is defined as the watched state. When the watched state executes, it will return a dictionary containing a key named "changes". Here are two examples of state return dictionaries, shown in json for clarity:

    {
        "local": {
            "file_|-/tmp/foo_|-/tmp/foo_|-directory": {
                "comment": "Directory /tmp/foo updated",
                "__run_num__": 0,
                "changes": {
                    "user": "bar"
                },
                "name": "/tmp/foo",
                "result": true
            }
        }
    }

    {
        "local": {
            "pkgrepo_|-salt-minion_|-salt-minion_|-managed": {
                "comment": "Package repo 'salt-minion' already configured",
                "__run_num__": 0,
                "changes": {},
                "name": "salt-minion",
                "result": true
            }
        }
    }

If the "result" of the watched state is `True`, the watching state will execute normally, and if it is `False`, the watching state will never run. This part of `watch` mirrors the functionality of the `require` requisite.

If the "result" of the watched state is `True` and the "changes" key contains a populated dictionary (changes occurred in the watched state), then the `watch` requisite can add additional behavior. This additional behavior is defined by the `mod_watch` function within the watching state module. If the `mod_watch` function exists in the watching state module, it will be called in addition to the normal watching state. The return data from the `mod_watch` function is what will be returned to the master in this case; the return data from the main watching function is discarded.

If the "changes" key contains an empty dictionary, the `watch` requisite acts exactly like the `require` requisite (the watching state will execute if "result" is `True`, and fail if "result" is `False` in the watched state).

Note

If the watching state `changes` key contains values, then `mod_watch` will not be called. If you're using `watch` or `watch_in` then it's a good idea to have a state that only enforces one attribute - such as splitting out `service.running` into its own state and have `service.enabled` in another.

One common source of confusion is expecting `mod_watch` to be called for every necessary change. You might be tempted to write something like this:

    httpd:
      service.running:
        - enable: True
        - watch:
          - file: httpd-config

    httpd-config:
      file.managed:
        - name: /etc/httpd/conf/httpd.conf
        - source: salt://httpd/files/apache.conf

If your service is already running but not enabled, you might expect that Salt will be able to tell that since the config file changed your service needs to be restarted. This is not the case. Because the service needs to be enabled, that change will be made and `mod_watch` will never be triggered. In this case, changes to your `apache.conf` will fail to be loaded. If you want to ensure that your service always reloads the correct way to handle this is either ensure that your service is not running before applying your state, or simply make sure that `service.running` is in a state on its own:

    enable-httpd:
      service.enabled:
        - name: httpd

    start-httpd:
      service.running:
        - name: httpd
        - watch:
          - file: httpd-config

    httpd-config:
      file.managed:
        - name: /etc/httpd/conf/httpd.conf
        - source: salt://httpd/files/apache.conf

Now that `service.running` is its own state, changes to `service.enabled` will no longer prevent `mod_watch` from getting triggered, so your `httpd` service will get restarted like you want.

#### listen

New in version 2014.7.0.

A `listen` requisite is used to trigger the `mod_watch` function of a state module. Rather than modifying execution order, the `mod_watch` state created by `listen` will execute at the end of the state run.

    restart-apache2:
      service.running:
        - name: apache2
        - listen:
          - file: /etc/apache2/apache2.conf

    configure-apache2:
      file.managed:
        - name: /etc/apache2/apache2.conf
        - source: salt://apache2/apache2.conf

This example will cause apache2 to restart when the apache2.conf file is changed, but the apache2 restart will happen at the end of the state run.

    restart-apache2:
      service.running:
        - name: apache2

    configure-apache2:
      file.managed:
        - name: /etc/apache2/apache2.conf
        - source: salt://apache2/apache2.conf
        - listen_in:
          - service: apache2

This example does the same as the above example, but puts the state argument on the file resource, rather than the service resource.

#### prereq

New in version 0.16.0.

The `prereq` requisite works similar to `onchanges` except that it uses the result from `test=True` on the observed state to determine if it should run prior to the observed state being run.

The best way to define how `prereq` operates is displayed in the following practical example: When a service should be shut down because underlying code is going to change, the service should be off-line while the update occurs. In this example, `graceful-down` is the pre-requiring state and `site-code` is the pre-required state.

    graceful-down:
      cmd.run:
        - name: service apache graceful
        - prereq:
          - file: site-code

    site-code:
      file.recurse:
        - name: /opt/site_code
        - source: salt://site/code

In this case, the apache server will only be shut down if the site-code state expects to deploy fresh code via the file.recurse call. The site-code deployment will only be executed if the graceful-down run completes successfully.

When a `prereq` requisite is evaluated, the pre-required state reports if it expects to have any changes. It does this by running the pre-required single state as a test-run by enabling `test=True`. This test-run will return a dictionary containing a key named "changes". (See the `watch` section above for examples of "changes" dictionaries.)

If the "changes" key contains a populated dictionary, it means that the pre-required state expects changes to occur when the state is actually executed, as opposed to the test-run. The pre-requiring state will now run. If the pre-requiring state executes successfully, the pre-required state will then execute. If the pre-requiring state fails, the pre-required state will not execute.

If the "changes" key contains an empty dictionary, this means that changes are not expected by the pre-required state. Neither the pre-required state nor the pre-requiring state will run.

#### onfail

New in version 2014.7.0.

The `onfail` requisite allows for reactions to happen strictly as a response to the failure of another state. This can be used in a number of ways, such as sending a notification or attempting an alternate task or thread of tasks when an important state fails.

The `onfail` requisite is applied in the same way as `require` and `watch`:

    primary_mount:
      mount.mounted:
        - name: /mnt/share
        - device: 10.0.0.45:/share
        - fstype: nfs

    backup_mount:
      mount.mounted:
        - name: /mnt/share
        - device: 192.168.40.34:/share
        - fstype: nfs
        - onfail:
          - mount: primary_mount

    build_site:
      cmd.run:
        - name: /srv/web/app/build_site

    notify-build_failure:
      hipchat.send_message:
        - room_id: 123456
        - message: "Building website fail on {{ salt.grains.get('id') }}"

The default behavior of the `onfail` when multiple requisites are listed is the opposite of other requisites in the salt state engine, it acts by default like `any()` instead of `all()`. This means that when you list multiple onfail requisites on a state, if any fail the requisite will be satisfied. If you instead need all logic to be applied, you can use `onfail_all` form:

    test_site_a:
      cmd.run:
        - name: ping -c1 10.0.0.1

    test_site_b:
      cmd.run:
        - name: ping -c1 10.0.0.2

    notify_site_down:
      hipchat.send_message:
        - room_id: 123456
        - message: "Both primary and backup sites are down!"
      - onfail_all:
        - cmd: test_site_a
        - cmd: test_site_b

In this contrived example notify_site_down will run when both 10.0.0.1 and 10.0.0.2 fail to respond to ping.

Note

Setting failhard (globally or in the failing state) to `True` will cause `onfail`, `onfail_in` and `onfail_any` requisites to be ignored. If you want to combine a global failhard set to True with `onfail`, `onfail_in` or `onfail_any`, you will have to explicitly set failhard to `False` (overriding the global setting) in the state that could fail.

Note

Beginning in the `2016.11.0` release of Salt, `onfail` uses OR logic for multiple listed `onfail` requisites. Prior to the `2016.11.0` release, `onfail` used AND logic. See Issue #22370 for more information. Beginning in the `Neon` release of Salt, a new `onfail_all` requisite form is available if AND logic is desired.

#### use

The `use` requisite is used to inherit the arguments passed in another id declaration. This is useful when many files need to have the same defaults.

    /etc/foo.conf:
      file.managed:
        - source: salt://foo.conf
        - template: jinja
        - mkdirs: True
        - user: apache
        - group: apache
        - mode: 755

    /etc/bar.conf:
      file.managed:
        - source: salt://bar.conf
        - use:
          - file: /etc/foo.conf

The `use` statement was developed primarily for the networking states but can be used on any states in Salt. This makes sense for the networking state because it can define a long list of options that need to be applied to multiple network interfaces.

The `use` statement does not inherit the requisites arguments of the targeted state. This means also a chain of `use` requisites would not inherit inherited options.

#### The _in version of requisites

Direct requisites form a dependency in a single direction. This makes it possible for Salt to detect cyclical dependencies and helps prevent faulty logic. In some cases, often in loops, it is desirable to establish a dependency in the opposite direction.

All direct requisites have an `_in` counterpart that behaves the same but forms the dependency in the opposite direction. The following sls examples will produce the exact same dependency mapping.

    httpd:
      pkg.installed: []
      service.running:
        - require:
          - pkg: httpd

    httpd:
      pkg.installed:
        - require_in:
          - service: httpd
      service.running: []

In the following example, Salt will not try to manage the nginx service or any configuration files unless the nginx package is installed because of the `pkg: nginx` requisite.

    nginx:
      pkg.installed: []
      service.running:
        - enable: True
        - reload: True
        - require:
          - pkg: nginx

php.sls

    include:
      - http

    php:
      pkg.installed:
        - require_in:
          - service: httpd

mod_python.sls

    include:
      - http

    mod_python:
      pkg.installed:
        - require_in:
          - service: httpd

Now the httpd server will only start if both php and mod_python are first verified to be installed. Thus allowing for a requisite to be defined "after the fact".

    {% for cfile in salt.pillar.get('nginx:config_files') %}
    /etc/nginx/conf.d/{{ cfile }}:
      file.managed:
        - source: salt://nginx/configs/{{ cfile }}
        - require:
          - pkg: nginx
        - listen_in:
          - service: nginx
    {% endfor %}

In this scenario, `listen_in` is a better choice than `require_in` because the `listen` requisite will trigger `mod_watch` behavior which will wait until the end of state execution and then reload the service.

#### The _any version of requisites

New in version 2018.3.0.

Some requisites have an `_any` counterpart that changes the requisite behavior from `all()` to `any()`.

    A:
      cmd.run:
        - name: echo A
        - require_any:
          - cmd: B
          - cmd: C

    B:
      cmd.run:
        - name: echo B

    C:
      cmd.run:
        - name: /bin/false

In this example A will run because at least one of the requirements specified, B or C, will succeed.

    myservice:
      pkg.installed

    /etc/myservice/myservice.conf:
      file.managed:
        - source: salt://myservice/files/myservice.conf

    /etc/yourservice/yourservice.conf:
      file.managed:
        - source: salt://yourservice/files/yourservice.conf

    /usr/local/sbin/myservice/post-changes-hook.sh
      cmd.run:
        - onchanges_any:
          - file: /etc/myservice/myservice.conf
          - file: /etc/your_service/yourservice.conf
        - require:
          - pkg: myservice

In this example, cmd.run would be run only if either of the file.managed states generated changes and at least one of the watched state's "result" is `True`.

### Altering States

The state altering system is used to make sure that states are evaluated exactly as the user expects. It can be used to double check that a state preformed exactly how it was expected to, or to make 100% sure that a state only runs under certain conditions. The use of unless or onlyif options help make states even more stateful. The `check_cmd` option helps ensure that the result of a state is evaluated correctly.

#### reload

`reload_modules` is a boolean option that forces salt to reload its modules after a state finishes. `reload_pillar` and `reload_grains` can also be set. See Reloading Modules.

    grains_refresh:
      module.run:
       - name: saltutil.refresh_grains
       - reload_grains: true

    grains_read:
      module.run:
       - name: grains.items

#### unless

New in version 2014.7.0.

The `unless` requisite specifies that a state should only run when any of the specified commands return `False`. The `unless` requisite operates as NAND and is useful in giving more granular control over when a state should execute.

NOTE: Under the hood `unless` calls `cmd.retcode` with `python_shell=True`. This means the commands referenced by `unless` will be parsed by a shell, so beware of side-effects as this shell will be run with the same privileges as the salt-minion. Also be aware that the boolean value is determined by the shell's concept of `True` and `False`, rather than Python's concept of `True` and `False`.

    vim:
      pkg.installed:
        - unless:
          - rpm -q vim-enhanced
          - ls /usr/bin/vim

In the example above, the state will only run if either the vim-enhanced package is not installed (returns `False`) or if /usr/bin/vim does not exist (returns `False`). The state will run if both commands return `False`.

However, the state will not run if both commands return `True`.

Unless checks are resolved for each name to which they are associated.

For example:

    deploy_app:
      cmd.run:
        - names:
          - first_deploy_cmd
          - second_deploy_cmd
        - unless: some_check

In the above case, `some_check` will be run prior to _each_ name -- once for `first_deploy_cmd` and a second time for `second_deploy_cmd`.

Changed in version 3000: The `unless` requisite can take a module as a dictionary field in unless. The dictionary must contain an argument `fun` which is the module that is being run, and everything else must be passed in under the args key or will be passed as individual kwargs to the module function.

    install apache on debian based distros:
      cmd.run:
        - name: make install
        - cwd: /path/to/dir/whatever-2.1.5/
        - unless:
          - fun: file.file_exists
            path: /usr/local/bin/whatever

    set mysql root password:
      debconf.set:
        - name: mysql-server-5.7
        - data:
            'mysql-server/root_password': {'type': 'password', 'value': {{pillar['mysql.pass']}} }
        - unless:
          - fun: pkg.version
            args:
              - mysql-server-5.7

Changed in version sodium: For modules which return a deeper data structure, the `get_return` key can be used to access results.

    test:
      test.nop:
        - name: foo
        - unless:
          - fun: consul.get
            consul_url: http://127.0.0.1:8500
            key:  not-existing
            get_return: res

#### onlyif

New in version 2014.7.0.

The `onlyif` requisite specifies that if each command listed in `onlyif` returns `True`, then the state is run. If any of the specified commands return `False`, the state will not run.

NOTE: Under the hood `onlyif` calls `cmd.retcode` with `python_shell=True`. This means the commands referenced by `onlyif` will be parsed by a shell, so beware of side-effects as this shell will be run with the same privileges as the salt-minion. Also be aware that the boolean value is determined by the shell's concept of `True` and `False`, rather than Python's concept of `True` and `False`.

    stop-volume:
      module.run:
        - name: glusterfs.stop_volume
        - m_name: work
        - onlyif:
          - gluster volume status work
        - order: 1

    remove-volume:
      module.run:
        - name: glusterfs.delete
        - m_name: work
        - onlyif:
          - gluster volume info work
        - watch:
          - cmd: stop-volume

The above example ensures that the stop_volume and delete modules only run if the gluster commands return a 0 ret value.

Changed in version 3000: The `onlyif` requisite can take a module as a dictionary field in onlyif. The dictionary must contain an argument `fun` which is the module that is being run, and everything else must be passed in under the args key or will be passed as individual kwargs to the module function.

    install apache on redhat based distros:
      pkg.latest:
        - name: httpd
        - onlyif:
          - fun: match.grain
            tgt: 'os_family:RedHat'

    install apache on debian based distros:
      pkg.latest:
        - name: apache2
        - onlyif:
          - fun: match.grain
            tgt: 'os_family:Debian'

    arbitrary file example:
      file.touch:
        - name: /path/to/file
        - onlyif:
          - fun: file.search
            args:
              - /etc/crontab
              - 'entry1'

Changed in version sodium: For modules which return a deeper data structure, the `get_return` key can be used to access results.

    test:
      test.nop:
        - name: foo
        - onlyif:
          - fun: consul.get
            consul_url: http://127.0.0.1:8500
            key:  does-exist
            get_return: res

### Creates

New in version 3001.

The `creates` requisite specifies that a state should only run when any of the specified files do not already exist. Like `unless`, `creates` requisite operates as NAND and is useful in giving more granular control over when a state should execute. This was previously used by the `cmd` and `docker_container` states.

>     contrived creates example:
>       file.touch:
>         - name: /path/to/file
>         - creates: /path/to/file

`creates` also accepts a list of files, in which case this state will run if any of the files do not exist:

>     creates list:
>       file.cmd:
>         - name: /path/to/command
>         - creates:
>             - /path/file
>             - /path/file2

#### runas

New in version 2017.7.0.

The `runas` global option is used to set the user which will be used to run the command in the `cmd.run` module.

    django:
      pip.installed:
        - name: django >= 1.6, <= 1.7
        - runas: daniel
        - require:
          - pkg: python-pip

In the above state, the pip command run by `cmd.run` will be run by the daniel user.

#### runas_password

New in version 2017.7.2.

The `runas_password` global option is used to set the password used by the runas global option. This is required by `cmd.run` on Windows when `runas` is specified. It will be set when `runas_password` is defined in the state.

    run_script:
      cmd.run:
        - name: Powershell -NonInteractive -ExecutionPolicy Bypass -File C:\\Temp\\script.ps1
        - runas: frank
        - runas_password: supersecret

In the above state, the Powershell script run by `cmd.run` will be run by the frank user with the password `supersecret`.

#### check_cmd

New in version 2014.7.0.

Check Command is used for determining that a state did or did not run as expected.

NOTE: Under the hood `check_cmd` calls `cmd.retcode` with `python_shell=True`. This means the command will be parsed by a shell, so beware of side-effects as this shell will be run with the same privileges as the salt-minion.

    comment-repo:
      file.replace:
        - name: /etc/yum.repos.d/fedora.repo
        - pattern: '^enabled=0'
        - repl: enabled=1
        - check_cmd:
          - "! grep 'enabled=0' /etc/yum.repos.d/fedora.repo"

This will attempt to do a replace on all `enabled=0` in the .repo file, and replace them with `enabled=1`. The `check_cmd` is just a bash command. It will do a grep for `enabled=0` in the file, and if it finds any, it will return a 0, which will be inverted by the leading `!`, causing `check_cmd` to set the state as failed. If it returns a 1, meaning it didn't find any `enabled=0`, it will be inverted by the leading `!`, returning a 0, and declaring the function succeeded.

NOTE: This requisite `check_cmd` functions differently than the `check_cmd` of the `file.managed` state.

#### Overriding Checks

There are two commands used for the above checks.

`mod_run_check` is used to check for `onlyif` and `unless`. If the goal is to override the global check for these to variables, include a `mod_run_check` in the salt/states/ file.

`mod_run_check_cmd` is used to check for the check_cmd options. To override this one, include a `mod_run_check_cmd` in the states file for the state.

## Fire Event Notifications

New in version 2015.8.0.

The fire_event option in a state will cause the minion to send an event to the Salt Master upon completion of that individual state.

The following example will cause the minion to send an event to the Salt Master with a tag of salt/state_result/20150505121517276431/dasalt/nano and the result of the state will be the data field of the event. Notice that the name of the state gets added to the tag.

    nano_stuff:
      pkg.installed:
        - name: nano
        - fire_event: True

In the following example instead of setting fire_event to True, fire_event is set to an arbitrary string, which will cause the event to be sent with this tag: salt/state_result/20150505121725642845/dasalt/custom/tag/nano/finished

    nano_stuff:
      pkg.installed:
        - name: nano
        - fire_event: custom/tag/nano/finished

## Retrying States

New in version 2017.7.0.

The retry option in a state allows it to be executed multiple times until a desired result is obtained or the maximum number of attempts have been made.

The retry option can be configured by the `attempts`, `until`, `interval`, and `splay` parameters.

The `attempts` parameter controls the maximum number of times the state will be run. If not specified or if an invalid value is specified, `attempts` will default to `2`.

The `until` parameter defines the result that is required to stop retrying the state. If not specified or if an invalid value is specified, `until` will default to `True`

The `interval` parameter defines the amount of time, in seconds, that the system will wait between attempts. If not specified or if an invalid value is specified, `interval` will default to `30`.

The `splay` parameter allows the `interval` to be additionally spread out. If not specified or if an invalid value is specified, `splay` defaults to `0` (i.e. no splaying will occur).

The following example will run the pkg.installed state until it returns `True` or it has been run `5` times. Each attempt will be `60` seconds apart and the interval will be splayed up to an additional `10` seconds:

    my_retried_state:
      pkg.installed:
        - name: nano
        - retry:
            attempts: 5
            until: True
            interval: 60
            splay: 10

The following example will run the pkg.installed state with all the defaults for `retry`. The state will run up to `2` times, each attempt being `30` seconds apart, or until it returns `True`.

    install_nano:
      pkg.installed:
        - name: nano
        - retry: True

The following example will run the file.exists state every `30` seconds up to `15` times or until the file exists (i.e. the state returns `True`).

    wait_for_file:
      file.exists:
        - name: /path/to/file
        - retry:
            attempts: 15
            interval: 30

### Return data from a retried state

When a state is retried, the returned output is as follows:

The `result` return value is the `result` from the final run. For example, imagine a state set to `retry` up to three times or `until` `True`. If the state returns `False` on the first run and then `True` on the second, the `result` of the state will be `True`.

The `started` return value is the `started` from the first run.

The `duration` return value is the total duration of all attempts plus the retry intervals.

The `comment` return value will include the result and comment from all previous attempts.

For example:

    wait_for_file:
      file.exists:
        - name: /path/to/file
        - retry:
            attempts: 10
            interval: 2
            splay: 5

Would return similar to the following. The state result in this case is `False` (file.exist was run 10 times with a 2 second interval, but the file specified did not exist on any run).

          ID: wait_for_file
    Function: file.exists
      Result: False
     Comment: Attempt 1: Returned a result of "False", with the following comment: "Specified path /path/to/file does not exist"
              Attempt 2: Returned a result of "False", with the following comment: "Specified path /path/to/file does not exist"
              Attempt 3: Returned a result of "False", with the following comment: "Specified path /path/to/file does not exist"
              Attempt 4: Returned a result of "False", with the following comment: "Specified path /path/to/file does not exist"
              Attempt 5: Returned a result of "False", with the following comment: "Specified path /path/to/file does not exist"
              Attempt 6: Returned a result of "False", with the following comment: "Specified path /path/to/file does not exist"
              Attempt 7: Returned a result of "False", with the following comment: "Specified path /path/to/file does not exist"
              Attempt 8: Returned a result of "False", with the following comment: "Specified path /path/to/file does not exist"
              Attempt 9: Returned a result of "False", with the following comment: "Specified path /path/to/file does not exist"
              Specified path /path/to/file does not exist
     Started: 09:08:12.903000
    Duration: 47000.0 ms
     Changes: