The following items are new for Chef Infra Client 12.11 and/or are changes from previous versions. The short version:

- **Support for standard exit codes in Chef client** Standard exit
    codes are now used by Chef client and should be identical across all
    OS platforms. New configuration setting `exit_status` has been added
    to specify how Chef client reports non-standard exit codes.
- **New data collector functionality for run statistics** New feature
    that provides a unified method for sharing statistics about your
    Chef runs in webhook-like manner.
- **Default chef-solo behavior is equivalent to chef-client local
    mode** chef-solo now uses chef-client local mode. To use the
    previous `chef-solo` behavior, run in `chef-solo --legacy-mode`.
- **New systemd_unit resource** Use the **systemd_unit** to manage
    systemd units.

## exit_status

When set to `:enabled`, chef-client will use [standardized exit
codes](https://github.com/chef/chef-rfc/blob/master/rfc062-exit-status.md#exit-codes-in-use)
for Chef client run status, and any non-standard exit codes will be
converted to `1` or `GENERIC_FAILURE`. This setting can also be set to
`:disabled` which preserves the old behavior of using non-standardized
exit codes and skips the deprecation warnings. Default value: `nil`.

<div class="admonition-note">
<p class="admonition-note-title">Note</p>
<div class="admonition-note-text">

The behavior with the default value consists of a warning on the use of
deprecated and non-standard exit codes. In a future release of Chef
client, using standardized exit codes will be the default behavior.

</div>
</div>

## Data collector

The data collector feature is new to Chef Infra Client 12.11. It provides a unified
method for sharing statistics about your Chef runs in a webhook-like
manner. The data collector supports Chef in all its modes: Chef client,
Chef solo (commonly referred to as "Chef client local mode"), and Chef
solo legacy mode.

To enable the data collector, specify the following settings in your
client configuration file:

- `data_collector.server_url`: Required. The URL to which the Chef
    client will POST the data collector messages
- `data_collector.token`: Optional. An token which will be sent in a
    x-data-collector-token HTTP header which can be used to authenticate
    the message.
- `data_collector.mode`: The Chef mode in which the data collector
    should run. Chef client mode is chef client configured to use Chef
    server to provide Chef client its resources and artifacts. Chef solo
    mode is Chef client configured to use a local Chef zero server
    (`chef-client --local-mode`). This setting also allows you to only
    enable data collector in Chef solo mode but not Chef client mode.
    Available options are `:solo`, `:client`, or `:both`. Default is
    `:both`.
- `data_collector.raise_on_failure`: If enabled, Chef will raise an
    exception and fail to run if the data collector cannot be reached at
    the start of the Chef run. Defaults to false.
- `data_collector.organization`: Optional. In Chef solo mode, the
    organization field in the messages will be set to this value.
    Default is `chef_solo`. This field does not apply to Chef client
    mode.

## Replace previous Chef-solo behavior with Chef client local mode

The default operation of chef-solo is now the equivalent to
`chef-client -z` or `chef-client --local-mode`, but you can use the
previous chef-solo behavior by running in `chef-solo --legacy-mode`. As
part of this change, environment and role files written in ruby are now
fully supported by `knife upload`.

## systemd_unit

Use the **systemd_unit** resource to create, manage, and run [systemd
units](https://www.freedesktop.org/software/systemd/man/systemd.html#Concepts).

### Syntax

A **systemd_unit** resource describes the configuration behavior for
systemd units. For example:

```ruby
systemd_unit 'sysstat-collect.timer' do
  content({
    'Unit' => {
      'Description' => 'Run system activity accounting tool every 10 minutes'
    },
    'Timer' => {
      'OnCalendar' => '*:00/10'
    },
    'Install' => {
      'WantedBy' => 'sysstat.service'
    }
  })
  action [:create, :enable, :start]
end
```

The full syntax for all of the properties that are available to the
**systemd_unit** resource is:

```ruby
systemd_unit 'name' do
  user                   String
  content                String or Hash
  triggers_reload        Boolean
end
```

where

- `name` is the name of the unit
- `user` is the user account that systemd units run under. If not
    specified, systemd units will run under the system account.
- `content` describes the behavior of the unit
- `triggers_reload` controls if a <span
    class="title-ref">daemon-reload</span> is executed to load the unit

### Actions

This resource has the following actions:

`:create`

:   Create a unit file, if it does not already exist.

`:delete`

:   Delete a unit file, if it exists.

`:enable`

:   Ensure the unit will be started after the next system boot.

`:disable`

:   Ensure the unit will not be started after the next system boot.

`:nothing`

:   Default. Do nothing with the unit.

`:mask`

:   Ensure the unit will not start, even to satisfy dependencies.

`:unmask`

:   Stop the unit from being masked and cause it to start as specified.

`:start`

:   Start a unit based in its systemd unit file.

`:stop`

:   Stop a running unit.

`:restart`

:   Restart a unit.

`:reload`

:   Reload the configuration file for a unit.

`:try_restart`

:   Try to restart a unit if the unit is running.

`:reload_or_restart`

:   For units that are services, this action reloads the configuration
    of the service without restarting, if possible; otherwise, it will
    restart the service so the new configuration is applied.

`:reload_or_try_restart`

:   For units that are services, this action reloads the configuration
    of the service without restarting, if possible; otherwise, it will
    try to restart the service so the new configuration is applied.

### Properties

This resource has the following properties:

`user`

:   **Ruby Type:** String

    The user account that the systemd unit process is run under. The
    path to the unit for that user would be something like
    `/etc/systemd/user/sshd.service`. If no user account is specified,
    the systemd unit will run under a `system` account, with the path to
    the unit being something like `/etc/systemd/system/sshd.service`.

`content`

:   **Ruby Type:** String, Hash

    A string or hash that contains a systemd [unit
    file](https://www.freedesktop.org/software/systemd/man/systemd.unit.html)
    definition that describes the properties of systemd-managed
    entities, such as services, sockets, devices, and so on.

`triggers_reload`

:   **Ruby Type:** true, false | **Default Value:** `true`

    Specifies whether to trigger a daemon reload when creating or
    deleting a unit.

`verify`

:   **Ruby Type:** true, false | **Default Value:** `true`

    Specifies if the unit will be verified before installation. Systemd
    can be overly strict when verifying units, so in certain cases it is
    preferable not to verify the unit.