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Delete Nodes (delete_nodes.yaml)

delete_nodes.yaml is used to safely remove specified nodes from the cluster, including eviction and deletion of nodes from Kubernetes, etcd decommissioning, CRI uninstallation, and DNS cleanup.

Execution Flow

  1. Global Initialization

    • Execute the native/root role on all nodes.
    • Load the defaults role on all nodes.

  2. etcd Node Scaling Down (external mode only)

    • For nodes in the etcd group that need to be uninstalled, execute in sequence:
      • etcd/prepare
      • etcd/scaling_down
      • etcd/postprocess
    • Triggered only when delete.etcd is true and the node is in the need_uninstall_etcd list.

  3. Ensure Control Plane Nodes Are Available

    • Execute pre-checks on kube_control_plane nodes to ensure at least one control plane node remains after deletion.
    • Also execute kubernetes/sync-etcd-config to sync etcd configuration to the remaining control plane nodes.

  4. Remove Node from Kubernetes Cluster

    • For nodes in the k8s_cluster group to be deleted, execute pre-tasks:
      • kubectl cordon: Prevent new Pods from being scheduled to the node.
      • kubectl drain: Evict workloads from the node.
      • If using Calico, execute calicoctl delete node.
      • kubectl delete node: Delete the node from the cluster.
    • Then execute:
      • uninstall/kubernetes: Uninstall Kubernetes components.
      • uninstall/cri: Uninstall the container runtime (if delete.cri is configured and the node does not belong to the image_registry group).

  5. Clean Local DNS Configuration

    • Clean up locally-written hosts marker segments by KubeKey.
    • Triggered only when delete.dns is true and the node is in the delete_nodes list.

  6. Uninstall etcd and Image Registry

    • Execute the etcd role on corresponding nodes to uninstall etcd (if delete.etcd is enabled).
    • Execute uninstall/image-registry on image_registry nodes (if delete.image_registry is enabled).

Notes

  • Before deleting a node, ensure that workloads on the node have been migrated or backed up.
  • Deleting control plane nodes will trigger additional safety checks to prevent accidental deletion that could cause cluster loss of control.