Version: 0.28.0

PolicyConfig Enterprise

Goal

Users sometimes need to enforce the same policy(s) with different configurations (parameters) for different targets (workspaces, namespaces, applications, or resources). The PolicyConfig CRD allows us to do that without duplicating policies by overriding policy parameters of multiple policies for a specific target.

Schema

The PolicyConfig CRD consists of two sections 1) match used to specify the target of this PolicyConfig and 2) config used to specify the policy parameters that will override the orginal policy parameters.

Expand to see a PolicyConfig example

apiVersion: pac.weave.works/v2beta2
kind: PolicyConfig      # policy config resource kind
metadata:
  name: my-config       # policy config name
spec:
  match:                # matches (targets of the policy config)
    workspaces:         # add one or more name workspaces
    - team-a
    - team-b
  config:               # config for policies [one or more]
    weave.policies.containers-minimum-replica-count:
      parameters:
        replica_count: 3

Each PolicyConfig CR can target either workspaces, namespaces, applications or resources. Targeting the same target explicitly in multiple PolicyConfigs is not allowed, ie: you can't use the same namespace in several PolicyConfigs which target namespaces.

To target workspaces:

  match:
    workspaces:
    - team-a
    - team-b

To target namespaces:

  match:
    namespaces:
    - dev
    - prod

To target applications:

  match:
    apps:            # add one or more apps [HelmRelease, Kustomization]
    - kind: HelmRelease
      name: my-app            # app name
      namespace: flux-system  # app namespace [if empty will match in any namespace]

To target resources:

  match:
    resources:       # add one or more resources [Deployment, ReplicaSet, ..]
    - kind: Deployment
      name: my-deployment     # resource name
      namespace: default      # resource namespace [if empty will match in any namespace]

Each PolicyConfig can override the parameters of one or more policies:

  config:               # config for policies [one or more]
    weave.policies.containers-minimum-replica-count: # the id of the policy
      parameters:
        replica_count: 3
        owner: owner-4
    weave.policies.containers-running-in-privileged-mode:
      parameters:
        privilege: true

Overlapping Targets

While it's not possible to create PolicyConfigs that explicitly target the same targets, it can happen implicitly ex: by targeting a namespace in a PolicyConfig and targeting an application that exists in this namespace in another. Whenever targets overlap, the narrower the scope of the PolicyConfig, the more precedence it has. Accordingly in the previous example, the configuration of the PolicyConfig targeting the application will have precedence over the PolicyConfig targeting the namespace.

Those are the possible targets from lowest to highest precendence:

PolicyConfig which targets a workspace.
PolicyConfig which targets a namespace.
PolicyConfig which targets an application in all namespaces.
PolicyConfig which targets an application in a certain namespace.
PolicyConfig which targets a kubernetes resource in all namespaces.
PolicyConfig which targets a kubernetes resource in a specific namespace.

Note:

All configs are applied from low priority to high priority while taking into consideration the common parameters between configs.
Each config only affects the parameters defined in it.

Example

We have a Kustomization application app-a and deployment deployment-1 which is part of this application.

Expand to see manifests

apiVersion: pac.weave.works/v2beta2
kind: PolicyConfig
metadata:
  name: my-config-1
spec:
  match:
    namespaces:
    - flux-system
  config:
    weave.policies.containers-minimum-replica-count:
      parameters:
        replica_count: 2
        owner: owner-1
---
apiVersion: pac.weave.works/v2beta2
kind: PolicyConfig
metadata:
  name: my-config-2
spec:
  match:
    apps:
    - kind: Kustomization
      name: app-a
  config:
    weave.policies.containers-minimum-replica-count:
      parameters:
        replica_count: 3
---
apiVersion: pac.weave.works/v2beta2
kind: PolicyConfig
metadata:
  name: my-config-3
spec:
  match:
    apps:
    - kind: Kustomization
      name: app-a
      namespace: flux-system
  config:
    weave.policies.containers-minimum-replica-count:
      parameters:
        replica_count: 4
---
apiVersion: pac.weave.works/v2beta2
kind: PolicyConfig
metadata:
  name: my-config-4
spec:
  match:
    resources:
    - kind: Deployment
      name: deployment-1
  config:
    weave.policies.containers-minimum-replica-count:
      parameters:
        replica_count: 5
        owner: owner-4
---

apiVersion: pac.weave.works/v2beta2
kind: PolicyConfig
metadata:
  name: my-config-5
spec:
  match:
    resources:
    - kind: Deployment
      name: deployment-1
      namespace: flux-system
  config:
    weave.policies.containers-minimum-replica-count:
      parameters:
        replica_count: 6

In the above example when you apply the 5 configurations...

app-a will be affected by my-config-5. It will be applied on the policies defined in it, which will affect deployment deployment-1 in namespace flux-system as it matches the kind, name and namespace.
note
Deploying deployment-1 in another namespace other than flux-system won't be affected by this configuration
Final config values will be as follows:
```
  config:
    weave.policies.containers-minimum-replica-count:
      parameters:
        replica_count: 6 # from my-config-5
        owner: owner-4   # from my-config-4
```
- Deployment deployment-1 in namespace flux-system, replica_count must be >= 6
- Also it will be affected by my-config-4 for owner configuration parameter owner: owner-4

In the above example when you apply my-config-1, my-config-2, my-config-3 and my-config-4

my-config-4 will be applied on the policies defined in it which will affect deployment deployment-1 in all namespaces as it matches the kind and name only.
Final config values will be as follows:
```
  config:
    weave.policies.containers-minimum-replica-count:
      parameters:
        replica_count: 5  # from my-config-4
        owner: owner-4    # from my-config-4
```
- Deployment deployment-1 in all namespaces replica_count must be >= 5
- Also it will be affected by my-config-4 for owner configuration parameter owner: owner-4

In the previous example when you apply my-config-1, my-config-2 and my-config-3

my-config-3 will be applied on the policies defined in it which will affect application app-a and all the resources in it in namespace flux-system as it matches the kind, name and namespace.
note
Deploying app-a in another namespace other than flux-system won't be affected by this configuration
Final config values will be the follows:
```
  config:
    weave.policies.containers-minimum-replica-count:
      parameters:
        replica_count: 4    # from my-config-3
        owner: owner-1      # from my-config-1
```
- Application app-a and all the resources in it in namespaces flux-system, replica_count must be >= 4
- Also it will be affected by my-config-1 for owner configuration parameter owner: owner-1

In the above example when you apply my-config-1 and my-config-2

my-config-2 will be applied on the policies defined in it which will affect application app-a and all the resources in it in all namespaces as it matches the kind and name only.
Final config values will be as follows:
```
  config:
    weave.policies.containers-minimum-replica-count:
      parameters:
        replica_count: 3   # from my-config-2
        owner: owner-1     # from my-config-1
```
- Application app-a and all the resources in all namespaces, replica_count must be >= 3
- Also it will be affected by my-config-1 for owner configuration parameter owner: owner-1

In the above example when you apply my-config-1

my-config-1 will be applied on the policies defined in it. which will affect the namespace flux-system with all applications and resources in it as it matches by namespace only.
Final config values will be as follows:
```
  config:
    weave.policies.containers-minimum-replica-count:
      parameters:
        replica_count: 2  # from my-config-1
        owner: owner-1    # from my-config-1
```
- Any application or resource in namespace flux-system, replica_count must be >= 2
- Also it will be affected by my-config-1 for owner configuration parameter owner: owner-1

PolicyConfig Enterprise

Goal​

Schema​

Overlapping Targets​

Example​

Goal

Schema

Overlapping Targets

Example