- Kubeadm: modified the etcd static Pod `liveness` and `readiness` probes to use a new etcd `v3.5.3+` HTTP(s) health check endpoint `/health?serializable=true` that allows to track the health of individual etcd members and not fail all members if a single member is not healthy in the etcd cluster. ([#110072](https://github.com/kubernetes/kubernetes/pull/110072), [@neolit123](https://github.com/neolit123))

}

// Type and constants for component health validation.
type ComponentConditionType string

// These are the valid conditions for the component.
const (
	ComponentHealthy ComponentConditionType = "Healthy"
)

// Information about the condition of a component.
type ComponentCondition struct {
	// Type of condition for a component.
	// Valid value: "Healthy"

	"type":    "Type of condition for a component. Valid value: \"Healthy\"",
	"status":  "Status of the condition for a component. Valid values for \"Healthy\": \"True\", \"False\", or \"Unknown\".",
	"message": "Message about the condition for a component. For example, information about a health check.",
	"error":   "Condition error code for a component. For example, a health check error code.",
}

message ComponentCondition {
  // Type of condition for a component.
  // Valid value: "Healthy"
  optional string type = 1;

  // Status of the condition for a component.
  // Valid values for "Healthy": "True", "False", or "Unknown".
  optional string status = 2;

  // Message about the condition for a component.
  // For example, information about a health check.
  // +optional
  optional string message = 3;

}

// Probe describes a health check to be performed against a container to determine whether it is
// alive or ready to receive traffic.
type Probe struct {
	// The action taken to determine the health of a container
	ProbeHandler
	// Length of time before health checking is activated.  In seconds.
	// +optional
	InitialDelaySeconds int32
	// Length of time before health checking times out.  In seconds.

- Fixes #115825. Kube-proxy will now include the `healthz` state in its response to the LB HC as to avoid indicating to the LB that it should use the node in question when Kube-proxy is not healthy. ([#111661](https://github.com/kubernetes/kubernetes/pull/111661), [@alexanderConstantinescu](https://github.com/alexanderConstantinescu)) [SIG Network]

- During device plugin allocation, resources requested by the pod can only be allocated if the device plugin has registered itself to kubelet AND healthy devices are present on the node to be allocated. If these conditions are not sattsfied, the pod would fail with `UnexpectedAdmissionError` error. ([#116376](https://github.com/kubernetes/kubernetes/pull/116376), [@swatisehgal](https://github.com/swatisehgal))...

			input: dedent.Dedent(`
				*filter
				:KUBE-SERVICES - [0:0]
				:KUBE-EXTERNAL-SERVICES - [0:0]
				:KUBE-FORWARD - [0:0]
				:KUBE-NODEPORTS - [0:0]
				-A KUBE-NODEPORTS -m comment --comment "ns2/svc2:p80 health check node port" -m tcp -p tcp --dport 30000 -j ACCEPT
				-A KUBE-FORWARD -m conntrack --ctstate INVALID -j DROP
				-A KUBE-FORWARD -m comment --comment "kubernetes forwarding rules" -m mark --mark 0x4000/0x4000 -j ACCEPT

            "items": {
              "default": "",
              "type": "string"
            },
            "type": "array",
            "x-kubernetes-list-type": "atomic"

- Kubeadm: during kubelet health checks, respect the healthz address:port configured in the KubeletConfiguration instead of hardcoding localhost:10248. ([#125286](https://github.com/kubernetes/kubernetes/pull/125286), [@neolit123](https://github.com/neolit123)) [SIG Cluster Lifecycle]