Struct k8s_openapi::api::core::v1::TopologySpreadConstraint

pub struct TopologySpreadConstraint {
    pub label_selector: Option<LabelSelector>,
    pub max_skew: i32,
    pub topology_key: String,
    pub when_unsatisfiable: String,
}

TopologySpreadConstraint specifies how to spread matching pods among the given topology.

Fields

label_selector: Option<LabelSelector>

LabelSelector is used to find matching pods. Pods that match this label selector are counted to determine the number of pods in their corresponding topology domain.

max_skew: i32

MaxSkew describes the degree to which pods may be unevenly distributed. When whenUnsatisfiable=DoNotSchedule, it is the maximum permitted difference between the number of matching pods in the target topology and the global minimum. For example, in a 3-zone cluster, MaxSkew is set to 1, and pods with the same labelSelector spread as 1/1/0: | zone1 | zone2 | zone3 | | P | P | | - if MaxSkew is 1, incoming pod can only be scheduled to zone3 to become 1/1/1; scheduling it onto zone1(zone2) would make the ActualSkew(2-0) on zone1(zone2) violate MaxSkew(1). - if MaxSkew is 2, incoming pod can be scheduled onto any zone. When whenUnsatisfiable=ScheduleAnyway, it is used to give higher precedence to topologies that satisfy it. It’s a required field. Default value is 1 and 0 is not allowed.

topology_key: String

TopologyKey is the key of node labels. Nodes that have a label with this key and identical values are considered to be in the same topology. We consider each <key, value> as a “bucket”, and try to put balanced number of pods into each bucket. It’s a required field.

when_unsatisfiable: String

WhenUnsatisfiable indicates how to deal with a pod if it doesn’t satisfy the spread constraint. - DoNotSchedule (default) tells the scheduler not to schedule it. - ScheduleAnyway tells the scheduler to schedule the pod in any location, but giving higher precedence to topologies that would help reduce the skew. A constraint is considered “Unsatisfiable” for an incoming pod if and only if every possible node assigment for that pod would violate “MaxSkew” on some topology. For example, in a 3-zone cluster, MaxSkew is set to 1, and pods with the same labelSelector spread as 3/1/1: | zone1 | zone2 | zone3 | | P P P | P | P | If WhenUnsatisfiable is set to DoNotSchedule, incoming pod can only be scheduled to zone2(zone3) to become 3/2/1(3/1/2) as ActualSkew(2-1) on zone2(zone3) satisfies MaxSkew(1). In other words, the cluster can still be imbalanced, but scheduler won’t make it more imbalanced. It’s a required field.

Trait Implementations

impl Clone for TopologySpreadConstraint

fn clone(&self) -> TopologySpreadConstraint

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for TopologySpreadConstraint

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

Formats the value using the given formatter.

impl Default for TopologySpreadConstraint

fn default() -> TopologySpreadConstraint

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for TopologySpreadConstraint

fn deserialize<D>(deserializer: D) -> Result<Self, D::Error> where
    D: Deserializer<'de>, 

Deserialize this value from the given Serde deserializer.

impl PartialEq<TopologySpreadConstraint> for TopologySpreadConstraint

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

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=.

impl Serialize for TopologySpreadConstraint

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 TopologySpreadConstraint