Struct PlacementConfig 

pub struct PlacementConfig {
    pub spread: Option<Vec<SpreadRule>>,
}

Topology spreading for the Pods backing a DNS server.

Controls how nameservers are distributed across failure domains, so a zone (or rack, or whatever your cluster labels nodes with) going down cannot take out every authoritative server at once.

placement can be set at two levels, resolved highest-priority first:

1. Bind9Instance.spec.placement — one specific DNS server
2. spec.primary.placement / spec.secondary.placement — one role, on the owning Bind9Cluster or ClusterBind9Provider

Resolution is whole-block: the more specific level wins outright rather than merging field-by-field, so what will be scheduled is answerable by reading one block.

Scope

This type deliberately covers only topology spreading. It is not a general pod-spec passthrough: nodeSelector, tolerations, and affinity are not accepted here. Embedding the full Kubernetes Affinity and Toleration schemas inflated the generated CRDs by roughly 450KB and would have handed a namespace tenant the scheduling primitives needed to place an operator-credentialed Pod onto a control-plane node — a large validation and security surface for a feature whose job is zone spreading. See docs/adr/0003-pod-placement-and-zone-spreading.md.

Example

placement:
  spread:
    - topologyKey: failure-domain.acme.io/rack
      maxSkew: 1
      whenUnsatisfiable: DoNotSchedule

Fields

spread: Option<Vec<SpreadRule>>

Topology spread rules applied to the Pods of this DNS server.

Three distinct states:

• absent — for a primary role with two or more servers, the operator applies its default: one soft (ScheduleAnyway) rule over topology.kubernetes.io/zone with maxSkew: 1. Secondaries and single-server roles get no constraint unless you ask for one.
• empty list (spread: []) — explicitly no spread constraints. Use this to opt a multi-primary cluster out of the default.
• non-empty list — exactly these rules, and no default. This is how secondaries opt in.

At most 8 rules; each becomes one topologySpreadConstraint, and every constraint is re-evaluated on each scheduling attempt.

Trait Implementations

impl Clone for PlacementConfig

fn clone(&self) -> PlacementConfig

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for PlacementConfig

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for PlacementConfig

fn default() -> PlacementConfig

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for PlacementConfig

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl JsonSchema for PlacementConfig

fn schema_name() -> Cow<'static, str>

The name of the generated JSON Schema.

fn schema_id() -> Cow<'static, str>

Returns a string that uniquely identifies the schema produced by this type.

fn json_schema(generator: &mut SchemaGenerator) -> Schema

Generates a JSON Schema for this type.

fn inline_schema() -> bool

Whether JSON Schemas generated for this type should be included directly in parent schemas, rather than being re-used where possible using the $ref keyword.

impl PartialEq for PlacementConfig

fn eq(&self, other: &PlacementConfig) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for PlacementConfig

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for PlacementConfig