Answer
NodeLease heartbeats from kubelet determine node health; missing heartbeats mark node Unready.
Quick Answer
kubelet sends node heartbeats by updating a Lease object in the kube-node-lease namespace every 10 seconds. The node controller monitors these leases. If a lease isn't updated within the lease duration (default 40s), the node controller marks the node NotReady. In large clusters, using Lease objects (small, cheap) instead of full Node status updates drastically reduces API server load.
S
SugharaIQ Editorial Team
Verified Answer
This answer has been peer-reviewed by industry experts holding senior engineering roles to ensure technical accuracy and relevance for modern interview standards.
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Source: SugharaIQ