In Anthos on bare metal, you add or remove nodes in a cluster by
editing the cluster's nodepool definitions. You can use the
command to change these definitions.
There are three different kinds of node pools in Anthos on bare metal: control plane, load balancer, and worker node pools. You edit control plane and load balancer nodes through the definitions in their associated cluster resources, while you edit worker node pool definitions directly.
Viewing node status
You can view the status of nodes and their respective node pools with the
kubectl get command.
For example, the following command shows the status of the node pools in the
kubectl -n my-cluster get nodepools.baremetal.cluster.gke.io
The system returns results similar to the following:
NAME READY RECONCILING STALLED UNDERMAINTENANCE UNKNOWN my-cluster 3 0 0 0 0 my-cluster-lb 2 0 0 0 0 np1 3 0 0 0 0
If you need more information on diagnosing your clusters, see Diagnosing and resetting clusters.
Changing control plane nodes
You add or remove control plane nodes by editing a cluster's
spec.controlPlane.nodePoolSpec.nodes array of addresses in the
cluster resource definition.
Note that editing the control plane nodepool directly doesn't work, because the cluster specification is the authoritative definition of the control plane node pool.
In a high availability (HA) configuration, an odd number of control plane node pools (three or more) are required to establish a quorum to ensure that if a control plane fails, others will take over. If you have an even number of nodes temporarily while ading or removing nodes for maintenance or replacement, your deployment maintains HA as long as you have enough quorum.
Changing load balancer nodes
You can add or remove a cluster's load balancer node pools by editing the cluster's
spec.loadBalancer.nodePoolSpec.nodes array of addresses in the cluster config
Changing worker nodes
You can add or remove worker nodes directly with the
Worker node pools must have at least one desired node.
In the following example, the command deletes a nodepool named
the variable for the cluster namespace is
kubectl -n my-cluster delete nodepool np1
Similarly, node pools can be resized by editing the
spec.nodes array of addresses.
Note that when you remove nodes from a cluster, they are first drained of any pods. Nodes will not be removed from the cluster if pods can't be rescheduled on other nodes. Removing nodes only removes the node from the control plane; the contents of the node are not reset.
kubectl edit command lets you edit and then commit changes
for the cluster namespace my-cluster and the nodepool np1:
kubectl -n my-cluster edit nodepool np1