Version 1.10. This is the most recent version. It's supported as outlined in the Anthos version support policy, offering the latest patches and updates for security vulnerabilities, exposures, and issues impacting Anthos clusters on bare metal. For release details, see the release notes 1.10. For a complete list of each minor and patch release in chronological order, see the combined release notes.

Available supported versions: 1.10  |   1.9  |   1.8  |  

Force-removing broken nodes in Anthos clusters on bare metal

When a node is broken and needs to be removed from a cluster for repair or replacement, you can force its removal from the cluster.

Force-removing worker nodes

In Anthos clusters on bare metal, you can add an annotation to mark a node for force removal.

After removing the node from the parent nodepool, run the following command to annotate the corresponding failing machine with the baremetal.cluster.gke.io/force-remove annotation. The value of the annotation itself does not matter:

kubectl --kubeconfig ADMIN_KUBECONFIG -n CLUSTER_NAMESPACE \
  annotate machine 10.200.0.8 baremetal.cluster.gke.io/force-remove=true

Anthos clusters on bare metal removes the node successfully.

Force-removing Control Plane nodes

Force-removing a control plane node is similar to performing a kubeadm reset on control plane nodes, and requires additional steps.

To force-remove a control plane node from the node pools, you need to take the following actions against the cluster that contains the failing control plane node:

  • remove the failing etcd member running on the failing node from the etcd cluster
  • update the ClusterStatus in the kube to remove the corresponding apiEndpoint.

Removing a failing etcd member

To remove the failing control plan node, first run etcdctl on the remaining healthy etcd pods. For more general information on this operation, see this Kubernetes documentation.

In the following procedure, CLUSTER_KUBECONFIG is the path to the kubeconfig file of the cluster.

  1. Look up the etcd pod with the following command:

    kubectl --kubeconfig CLUSTER_KUBECONFIG get \
     pod -n kube-system -l component=etcd -o wide
    

    The command returns the following list of nodes. For this example, assume node 10.200.0.8 is inaccessible and unrecoverable:

    NAME                READY   STATUS    RESTARTS   AGE     IP           NODE
    etcd-357b68f4ecf0   1/1     Running   0          9m2s    10.200.0.6   357b68f4ecf0
    etcd-7d7c21db88b3   1/1     Running   0          33m     10.200.0.7   7d7c21db88b3
    etcd-b049141e0802   1/1     Running   0          8m22s   10.200.0.8   b049141e0802
    

  2. Exec into one of the remaining healthy etcd pods:

    kubectl --kubeconfig CLUSTER_KUBECONFIG exec -it -n \
    kube-system etcd-357b68f4ecf0 -- /bin/sh
    
  3. Look up the current members to find the ID of the failing member. The command will return a list:

    etcdctl --endpoints=https://10.200.0.6:2379,https://10.200.0.7:2379 --key=/etc/kubernetes/pki/etcd/peer.key \
    --cacert=/etc/kubernetes/pki/etcd/ca.crt --cert=/etc/kubernetes/pki/etcd/peer.crt  member list
    

    This command returns, for example:

    23da9c3f2594532a, started, 7d7c21db88b3, https://10.200.0.6:2380, https://10.200.0.6:2379, false
    772c1a54956b7f51, started, 357b68f4ecf0, https://10.200.0.7:2380, https://10.200.0.7:2379, false
    f64f66ad8d3e7960, started, b049141e0802, https://10.200.0.8:2380, https://10.200.0.8:2379, false
    
  4. Remove the failing member:

    etcdctl --endpoints=https://10.200.0.6:2379,https://10.200.0.7:2379 --key=/etc/kubernetes/pki/etcd/peer.key \
    --cacert=/etc/kubernetes/pki/etcd/ca.crt --cert=/etc/kubernetes/pki/etcd/peer.crt \
     member remove f64f66ad8d3e7960
    

Updating ClusterStatus and removing the failing apiEndpoint

In the following procedure, CLUSTER_KUBECONFIG is the path to the kubeconfig file of the cluster.

  1. Look up the ClusterStatus section inside the kubeadm-config config map:

    kubectl --kubeconfig CLUSTER_KUBECONFIG describe configmap -n \
    kube-system kubeadm-config
    

    The command returns results similar to those shown below:

    ...
    ClusterStatus:
    ----
    apiEndpoints:
    7d7c21db88b3:
      advertiseAddress: 10.200.0.6
      bindPort: 6444
    357b68f4ecf0:
      advertiseAddress: 10.200.0.7
      bindPort: 6444
    b049141e0802:
      advertiseAddress: 10.200.0.8
      bindPort: 6444
    apiVersion: kubeadm.k8s.io/v1beta2
    kind: ClusterStatus
    ...
    
  2. Edit the config map to remove the section that contains the failing IP (this example shows the results of removing 10.200.0.8 using the kubectl edit command):

    kubectl --kubeconfig CLUSTER_KUBECONFIG edit configmap \
    -n kube-system kubeadm-config
    

    After editing, the config map looks similar to the following:

    ...
    ClusterStatus: |
      apiEndpoints:
        7d7c21db88b3:
          advertiseAddress: 10.200.0.6
          bindPort: 6444
        357b68f4ecf0:
          advertiseAddress: 10.200.0.7
          bindPort: 6444
      apiVersion: kubeadm.k8s.io/v1beta2
      kind: ClusterStatus
    ...
    
  3. When you save the edited config map, the failing node is removed from the cluster.