source/custom: drop support for the legacy rule format

Author: marquiz

docs/usage/customization-guide.md

@@ -1062,278 +1062,3 @@ must be present):
           vendor: "0fff"
           device: "abcd"
 ```
-
-## Legacy custom rule syntax
-
-**DEPRECATED**: use the new rule syntax instead.
-
-The `custom` source supports the legacy `matchOn` rule syntax for
-backwards-compatibility.
-
-To aid in making the legacy rule syntax clearer, we define a general and a per
-rule nomenclature, keeping things as consistent as possible.
-
-### General nomenclature and definitions
-
-```plaintext
-Rule        :Represents a matching logic that is used to match on a feature.
-Rule Input  :The input a Rule is provided. This determines how a Rule performs the match operation.
-Matcher     :A composition of Rules, each Matcher may be composed of at most one instance of each Rule.
-```
-
-### Custom features format (using the nomenclature defined above)
-
-Rules are specified under `sources.custom` in the nfd-worker configuration
-file.
-
-```yaml
-sources:
-  custom:
-  - name: <feature name>
-    value: <optional feature value, defaults to "true">
-    matchOn:
-    - <Rule-1>: <Rule-1 Input>
-      [<Rule-2>: <Rule-2 Input>]
-    - <Matcher-2>
-    - ...
-    - ...
-    - <Matcher-N>
-  - <custom feature 2>
-  - ...
-  - ...
-  - <custom feature M>
-```
-
-The label is constructed by adding `custom-` prefix to the name field, label
-value defaults to `true` if not specified in the rule spec:
-
-```plaintext
-feature.node.kubernetes.io/custom-<name> = <value>
-```
-
-### Matching process
-
-Specifying Rules to match on a feature is done by providing a list of Matchers.
-Each Matcher contains one or more Rules.
-
-Logical _OR_ is performed between Matchers and logical _AND_ is performed
-between Rules of a given Matcher.
-
-### Rules
-
-#### pciid rule
-
-##### Nomenclature
-
-```plaintext
-Attribute   :A PCI attribute.
-Element     :An identifier of the PCI attribute.
-```
-
-The PciId Rule allows matching the PCI devices in the system on the following
-Attributes: `class`,`vendor` and `device`. A list of Elements is provided for
-each Attribute.
-
-##### Format
-
-```yaml
-pciId :
-  class: [<class id>, ...]
-  vendor: [<vendor id>,  ...]
-  device: [<device id>, ...]
-```
-
-Matching is done by performing a logical _OR_ between Elements of an Attribute
-and logical _AND_ between the specified Attributes for each PCI device in the
-system.  At least one Attribute must be specified. Missing attributes will not
-partake in the matching process.
-
-#### UsbId rule
-
-##### Nomenclature
-
-```plaintext
-Attribute   :A USB attribute.
-Element     :An identifier of the USB attribute.
-```
-
-The UsbId Rule allows matching the USB devices in the system on the following
-Attributes: `class`,`vendor`, `device` and `serial`. A list of Elements is
-provided for each Attribute.
-
-##### Format
-
-```yaml
-usbId :
-  class: [<class id>, ...]
-  vendor: [<vendor id>,  ...]
-  device: [<device id>, ...]
-  serial: [<serial>, ...]
-```
-
-Matching is done by performing a logical _OR_ between Elements of an Attribute
-and logical _AND_ between the specified Attributes for each USB device in the
-system.  At least one Attribute must be specified. Missing attributes will not
-partake in the matching process.
-
-#### LoadedKMod rule
-
-##### Nomenclature
-
-```plaintext
-Element     :A kernel module
-```
-
-The LoadedKMod Rule allows matching the loaded kernel modules in the system
-against a provided list of Elements.
-
-##### Format
-
-```yaml
-loadedKMod : [<kernel module>, ...]
-```
-
-Matching is done by performing logical _AND_ for each provided Element, i.e
-the Rule will match if all provided Elements (kernel modules) are loaded in the
-system.
-
-#### CpuId rule
-
-##### Nomenclature
-
-```plaintext
-Element     :A CPUID flag
-```
-
-The Rule allows matching the available CPUID flags in the system against a
-provided list of Elements.
-
-##### Format
-
-```yaml
-cpuId : [<CPUID flag string>, ...]
-```
-
-Matching is done by performing logical _AND_ for each provided Element, i.e the
-Rule will match if all provided Elements (CPUID flag strings) are available in
-the system.
-
-#### Kconfig rule
-
-##### Nomenclature
-
-```plaintext
-Element     :A Kconfig option
-```
-
-The Rule allows matching the kconfig options in the system against a provided
-list of Elements.
-
-##### Format
-
-```yaml
-kConfig: [<kernel config option ('y' or 'm') or '=<value>'>, ...]
-```
-
-Matching is done by performing logical _AND_ for each provided Element, i.e the
-Rule will match if all provided Elements (kernel config options) are enabled
-(`y` or `m`) or matching `=<value>` in the kernel.
-
-#### Nodename rule
-
-##### Nomenclature
-
-```plaintext
-Element     :A nodename regexp pattern
-```
-
-The Rule allows matching the node's name against a provided list of Elements.
-
-##### Format
-
-```yaml
-nodename: [ <nodename regexp pattern>, ... ]
-```
-
-Matching is done by performing logical _OR_ for each provided Element, i.e the
-Rule will match if one of the provided Elements (nodename regexp pattern)
-matches the node's name.
-
-### Legacy custom rule example
-
-```yaml
-custom:
-  - name: "my.kernel.feature"
-    matchOn:
-      - loadedKMod: ["kmod1", "kmod2"]
-  - name: "my.pci.feature"
-    matchOn:
-      - pciId:
-          vendor: ["15b3"]
-          device: ["1014", "1017"]
-  - name: "my.usb.feature"
-    matchOn:
-      - usbId:
-          vendor: ["1d6b"]
-          device: ["0003"]
-          serial: ["090129a"]
-  - name: "my.combined.feature"
-    matchOn:
-      - loadedKMod : ["vendor_kmod1", "vendor_kmod2"]
-        pciId:
-          vendor: ["15b3"]
-          device: ["1014", "1017"]
-  - name: "vendor.feature.node.kubernetes.io/accumulated.feature"
-    matchOn:
-      - loadedKMod : ["some_kmod1", "some_kmod2"]
-      - pciId:
-          vendor: ["15b3"]
-          device: ["1014", "1017"]
-  - name: "my.kernel.featureneedscpu"
-    matchOn:
-      - kConfig: ["KVM_INTEL"]
-      - cpuId: ["VMX"]
-  - name: "my.kernel.modulecompiler"
-    matchOn:
-      - kConfig: ["GCC_VERSION=100101"]
-        loadedKMod: ["kmod1"]
-  - name: "profile.node.kubernetes.io/my-datacenter"
-    value: "datacenter-1"
-    matchOn:
-      - nodename: [ "node-datacenter1-rack.*-server.*" ]
-```
-
-__In the example above:__
-
-- A node would contain the label:
-  `feature.node.kubernetes.io/custom-my.kernel.feature=true` if the node has
-  `kmod1` _AND_ `kmod2` kernel modules loaded.
-- A node would contain the label:
-  `feature.node.kubernetes.io/custom-my.pci.feature=true` if the node contains
-  a PCI device with a PCI vendor ID of `15b3` _AND_ PCI device ID of `1014` _OR_
-  `1017`.
-- A node would contain the label:
-  `feature.node.kubernetes.io/custom-my.usb.feature=true` if the node contains
-  a USB device with a USB vendor ID of `1d6b` _AND_ USB device ID of `0003`.
-- A node would contain the label:
-  `feature.node.kubernetes.io/custom-my.combined.feature=true` if
-  `vendor_kmod1` _AND_ `vendor_kmod2` kernel modules are loaded __AND__ the node
-  contains a PCI device
-  with a PCI vendor ID of `15b3` _AND_ PCI device ID of `1014` _or_ `1017`.
-- A node would contain the label:
-  `vendor.feature.node.kubernetes.io/accumulated.feature=true` if
-  `some_kmod1` _AND_ `some_kmod2` kernel modules are loaded __OR__ the node
-  contains a PCI device
-  with a PCI vendor ID of `15b3` _AND_ PCI device ID of `1014` _OR_ `1017`.
-- A node would contain the label:
-  `feature.node.kubernetes.io/custom-my.kernel.featureneedscpu=true` if
-  `KVM_INTEL` kernel config is enabled __AND__ the node CPU supports `VMX`
-  virtual machine extensions
-- A node would contain the label:
-  `feature.node.kubernetes.io/custom-my.kernel.modulecompiler=true` if the
-  in-tree `kmod1` kernel module is loaded __AND__ it's built with
-  `GCC_VERSION=100101`.
-- A node would contain the label:
-  `profile.node.kubernetes.io/my-datacenter=datacenter-1` if the node's name
-  matches the `node-datacenter1-rack.*-server.*` pattern, e.g.
-  `node-datacenter1-rack2-server42`