Support templating of var names in a similar manner as labels. Add
support for a new 'varsTemplate' field to the feature rule spec which is
treated similarly to the 'labelsTemplate' field. The value of the field
is processed through the golang "text/template" template engine and the
expanded value must contain variables in <key>=<value> format, separated
by newlines i.e.:
- name: <rule-name>
varsTemplate: |
<label-1>=<value-1>
<label-2>=<value-2>
...
Similar rules as for 'labelsTemplate' apply, i.e.
1. In case of matchAny is specified, the template is executed separately
against each individual matchFeatures matcher.
2. 'vars' field has priority over 'varsTemplate'
Support backreferencing of output values from previous rules. Enables
complex rule setups where custom features are further combined together
to form even more sophisticated higher level labels. The labels created
by preceding rules are available as a special 'rule.matched' feature
(for matchFeatures to use).
If referencing rules accross multiple configs/CRDs care must be taken
with the ordering. Processing order of rules in nfd-worker:
1. Static rules
2. Files from /etc/kubernetes/node-feature-discovery/custom.d/
in alphabetical order. Subdirectories are processed by reading their
files in alphabetical order.
3. Custom rules from main nfd-worker.conf
In nfd-master, NodeFeatureRule objects are processed in alphabetical
order (based on their metadata.name).
This patch also adds new 'vars' fields to the rule spec. Like 'labels',
it is a map of key-value pairs but no labels are generated from these.
The values specified in 'vars' are only added for backreferencing into
the 'rules.matched' feature. This may by desired in schemes where the
output of certain rules is only used as intermediate variables for other
rules and no labels out of these are wanted.
An example setup:
- name: "kernel feature"
labels:
kernel-feature:
matchFeatures:
- feature: kernel.version
matchExpressions:
major: {op: Gt, value: ["4"]}
- name: "intermediate var feature"
vars:
nolabel-feature: "true"
matchFeatures:
- feature: cpu.cpuid
matchExpressions:
AVX512F: {op: Exists}
- feature: pci.device
matchExpressions:
vendor: {op: In, value: ["8086"]}
device: {op: In, value: ["1234", "1235"]}
- name: top-level-feature
matchFeatures:
- feature: rule.matched
matchExpressions:
kernel-feature: "true"
nolabel-feature: "true"
Require that the expanded LabelsTemplate has values. That is, the
(expanded) template must consist of key=value pairs separated by
newlines. No default value will be assigned and we now return an error
if a (non-empty) line not conforming with the key=value format is
encountered.
Commit c8d73666d described that the value defaults to "true" if not
specified. That was not the case and we defaulted to an empty string,
instead.
An example:
- name: "my rule"
labelsTemplate: |
my.label.1=foo
my.label.2=
Would create these labels:
"my.label.1": "foo"
"my.label.2": ""
Further, the following:
- name: "my failing rule"
labelsTemplate: |
my.label.3
will cause an error in the rule processing.
Support templating of label names in feature rules. It is available both
in NodeFeatureRule CRs and in custom rule configuration of nfd-worker.
This patch adds a new 'labelsTemplate' field to the rule spec, making it
possible to dynamically generate multiple labels per rule based on the
matched features. The feature relies on the golang "text/template"
package. When expanded, the template must contain labels in a raw
<key>[=<value>] format (where 'value' defaults to "true"), separated by
newlines i.e.:
- name: <rule-name>
labelsTemplate: |
<label-1>[=<value-1>]
<label-2>[=<value-2>]
...
All the matched features of 'matchFeatures' directives are available for
templating engine in a nested data structure that can be described in
yaml as:
.
<domain-1>:
<key-feature-1>:
- Name: <matched-key>
- ...
<value-feature-1:
- Name: <matched-key>
Value: <matched-value>
- ...
<instance-feature-1>:
- <attribute-1-name>: <attribute-1-value>
<attribute-2-name>: <attribute-2-value>
...
- ...
<domain-2>:
...
That is, the per-feature data available for matching depends on the type
of feature that was matched:
- "key features": only 'Name' is available
- "value features": 'Name' and 'Value' can be used
- "instance features": all attributes of the matched instance are
available
NOTE: In case of matchAny is specified, the template is executed
separately against each individual matchFeatures matcher and the
eventual set of labels is a superset of all these expansions. Consider
the following:
- name: <name>
labelsTemplate: <template>
matchAny:
- matchFeatures: <matcher#1>
- matchFeatures: <matcher#2>
matchFeatures: <matcher#3>
In the example above (assuming the overall result is a match) the
template would be executed on matcher#1 and/or matcher#2 (depending on
whether both or only one of them match), and finally on matcher#3, and
all the labels from these separate expansions would be created (i.e. the
end result would be a union of all the individual expansions).
NOTE 2: The 'labels' field has priority over 'labelsTemplate', i.e.
labels specified in the 'labels' field will override any labels
originating from the 'labelsTemplate' field.
A special case of an empty match expression set matches everything (i.e.
matches/returns all existing keys/values). This makes it simpler to
write templates that run over all values. Also, makes it possible to
later implement support for templates that run over all _keys_ of a
feature.
Some example configurations:
- name: "my-pci-template-features"
labelsTemplate: |
{{ range .pci.device }}intel-{{ .class }}-{{ .device }}=present
{{ end }}
matchFeatures:
- feature: pci.device
matchExpressions:
class: {op: InRegexp, value: ["^06"]}
vendor: ["8086"]
- name: "my-system-template-features"
labelsTemplate: |
{{ range .system.osrelease }}system-{{ .Name }}={{ .Value }}
{{ end }}
matchFeatures:
- feature: system.osRelease
matchExpressions:
ID: {op: Exists}
VERSION_ID.major: {op: Exists}
Imaginative template pipelines are possible, of course, but care must be
taken in order to produce understandable and maintainable rule sets.
Implement a private helper type (nameTemplateHelper) for handling
(executing and caching) of templated names. DeepCopy methods are
manually implemented as controller-gen is not able to help with that.
Add auto-generated code for interfacing our CRD API. On top of this, a
CR controller can be implemented. This patch uses k8s/code-generator
for code generation. Run "make generate" in order to (re-)generate
everything. Path to the code-generator repository may need to be
specified:
K8S_CODE_GENERATOR=path/to/code-generator make apigen
Code-generator version 0.20.7 was used to create this patch. Install
k8s code-generator tools and clone the repo with:
git clone https://github.com/kubernetes/code-generator -b v0.20.7 <path/to/code-generator>
go install k8s.io/code-generator/cmd/...(at)v0.20.7
Move the rule processing of matchFeatures and matchAny from
source/custom package over to pkg/apis/nfd, aiming for better integrity
and re-usability of the code. Does not change the CRD API as such, just
adds more supportive functions.
Having a dedicated type makes it possible to specify deepcopy functions
for it. We need to do this manually as deepcopy-gen doesn't know how to
create copies of regexps.
Add a cluster-scoped Custom Resource Definition for specifying labeling
rules. Nodes (node features, node objects) are cluster-level objects and
thus the natural and encouraged setup is to only have one NFD deployment
per cluster - the set of underlying features of the node stays the same
independent of how many parallel NFD deployments you have. Our extension
points (hooks, feature files and now CRs) can be be used by multiple
actors (depending on us) simultaneously. Having the CRD cluster-scoped
hopefully drives deployments in this direction. It also should make
deployment of vendor-specific labeling rules easy as there is no need to
worry about the namespace.
This patch virtually replicates the source.custom.FeatureSpec in a CRD
API (located in the pkg/apis/nfd/v1alpha1 package) with the notable
exception that "MatchOn" legacy rules are not supported. Legacy rules
are left out in order to keep the CRD simple and clean.
The duplicate functionality in source/custom will be dropped by upcoming
patches.
This patch utilizes controller-gen (from sigs.k8s.io/controller-tools)
for generating the CRD and deepcopy methods. Code can be (re-)generated
with "make generate". Install controller-gen with:
go install sigs.k8s.io/controller-tools/cmd/controller-gen@v0.7.0
Update kustomize and helm deployments to deploy the CRD.
Create a new package pkg/apis/nfd/v1alpha1 and migrate the custom rule
expressions over there. This is the first step in creating a new CRD API
for custom rules.
