Class V1TopologySpreadConstraint
TopologySpreadConstraint specifies how to spread matching pods among the given
topology.
Inheritance
V1TopologySpreadConstraint
Assembly: KubernetesClient.dll
Syntax
public record V1TopologySpreadConstraint : IEquatable<V1TopologySpreadConstraint>
Constructors
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V1TopologySpreadConstraint()
Declaration
public V1TopologySpreadConstraint()
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V1TopologySpreadConstraint(V1TopologySpreadConstraint)
Declaration
protected V1TopologySpreadConstraint(V1TopologySpreadConstraint original)
Parameters
Properties
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EqualityContract
Declaration
protected virtual Type EqualityContract { get; }
Property Value
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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.
Declaration
[JsonPropertyName("labelSelector")]
public V1LabelSelector LabelSelector { get; set; }
Property Value
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MatchLabelKeys
MatchLabelKeys is a set of pod label keys to select the pods over which
spreading will be calculated. The keys are used to lookup values from the
incoming pod labels, those key-value labels are ANDed with labelSelector to
select the group of existing pods over which spreading will be calculated for
the incoming pod. The same key is forbidden to exist in both MatchLabelKeys and
LabelSelector. MatchLabelKeys cannot be set when LabelSelector isn't set. Keys
that don't exist in the incoming pod labels will be ignored. A null or empty
list means only match against labelSelector.
This is a beta field and requires the MatchLabelKeysInPodTopologySpread feature
gate to be enabled (enabled by default).
Declaration
[JsonPropertyName("matchLabelKeys")]
public IList<string> MatchLabelKeys { get; set; }
Property Value
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MaxSkew
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. The global minimum is the minimum number of matching pods in an
eligible domain or zero if the number of eligible domains is less than
MinDomains. For example, in a 3-zone cluster, MaxSkew is set to 1, and pods with
the same labelSelector spread as 2/2/1: In this case, the global minimum is 1. |
zone1 | zone2 | zone3 | | P P | P P | P | - if MaxSkew is 1, incoming
pod can only be scheduled to zone3 to become 2/2/2; scheduling it onto
zone1(zone2) would make the ActualSkew(3-1) 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.
Declaration
[JsonPropertyName("maxSkew")]
public int MaxSkew { get; set; }
Property Value
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MinDomains
MinDomains indicates a minimum number of eligible domains. When the number of
eligible domains with matching topology keys is less than minDomains, Pod
Topology Spread treats "global minimum" as 0, and then the calculation of Skew
is performed. And when the number of eligible domains with matching topology
keys equals or greater than minDomains, this value has no effect on scheduling.
As a result, when the number of eligible domains is less than minDomains,
scheduler won't schedule more than maxSkew Pods to those domains. If value is
nil, the constraint behaves as if MinDomains is equal to 1. Valid values are
integers greater than 0. When value is not nil, WhenUnsatisfiable must be
DoNotSchedule.
For example, in a 3-zone cluster, MaxSkew is set to 2, MinDomains is set to 5
and pods with the same labelSelector spread as 2/2/2: | zone1 | zone2 | zone3 |
| P P | P P | P P | The number of domains is less than 5(MinDomains), so
"global minimum" is treated as 0. In this situation, new pod with the same
labelSelector cannot be scheduled, because computed skew will be 3(3 - 0) if new
Pod is scheduled to any of the three zones, it will violate MaxSkew.
Declaration
[JsonPropertyName("minDomains")]
public int? MinDomains { get; set; }
Property Value
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NodeAffinityPolicy
NodeAffinityPolicy indicates how we will treat Pod's nodeAffinity/nodeSelector
when calculating pod topology spread skew. Options are: - Honor: only nodes
matching nodeAffinity/nodeSelector are included in the calculations. - Ignore:
nodeAffinity/nodeSelector are ignored. All nodes are included in the
calculations.
If this value is nil, the behavior is equivalent to the Honor policy.
Declaration
[JsonPropertyName("nodeAffinityPolicy")]
public string NodeAffinityPolicy { get; set; }
Property Value
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NodeTaintsPolicy
NodeTaintsPolicy indicates how we will treat node taints when calculating pod
topology spread skew. Options are: - Honor: nodes without taints, along with
tainted nodes for which the incoming pod has a toleration, are included. -
Ignore: node taints are ignored. All nodes are included.
If this value is nil, the behavior is equivalent to the Ignore policy.
Declaration
[JsonPropertyName("nodeTaintsPolicy")]
public string NodeTaintsPolicy { get; set; }
Property Value
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TopologyKey
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. We define a domain as a particular instance of a topology. Also, we
define an eligible domain as a domain whose nodes meet the requirements of
nodeAffinityPolicy and nodeTaintsPolicy. e.g. If TopologyKey is
"kubernetes.io/hostname", each Node is a domain of that topology. And, if
TopologyKey is "topology.kubernetes.io/zone", each zone is a domain of that
topology. It's a required field.
Declaration
[JsonPropertyName("topologyKey")]
public string TopologyKey { get; set; }
Property Value
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WhenUnsatisfiable
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 assignment 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.
Declaration
[JsonPropertyName("whenUnsatisfiable")]
public string WhenUnsatisfiable { get; set; }
Property Value
Methods
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Equals(object?)
Declaration
public override bool Equals(object? obj)
Parameters
| Type |
Name |
Description |
| object |
obj |
|
Returns
Overrides
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Equals(V1TopologySpreadConstraint?)
Declaration
public virtual bool Equals(V1TopologySpreadConstraint? other)
Parameters
Returns
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GetHashCode()
Declaration
public override int GetHashCode()
Returns
Overrides
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PrintMembers(StringBuilder)
Declaration
protected virtual bool PrintMembers(StringBuilder builder)
Parameters
Returns
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ToString()
Declaration
public override string ToString()
Returns
Overrides
Operators
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operator ==(V1TopologySpreadConstraint?, V1TopologySpreadConstraint?)
Declaration
public static bool operator ==(V1TopologySpreadConstraint? left, V1TopologySpreadConstraint? right)
Parameters
Returns
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operator !=(V1TopologySpreadConstraint?, V1TopologySpreadConstraint?)
Declaration
public static bool operator !=(V1TopologySpreadConstraint? left, V1TopologySpreadConstraint? right)
Parameters
Returns
Implements