02-OS-Upgrades.md

OS Upgrades

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In this section, we will take a look at os upgrades.

If the node was down for more than 5 minutes, then the pods are terminated from that node

• You can purposefully drain the node of all the workloads so that the workloads are moved to other nodes.

  $ kubectl drain node-1
  

• The node is also cordoned or marked as unschedulable.

• When the node is back online after a maintenance, it is still unschedulable. You then need to uncordorn it.

  $ kubectl uncordorn node-1
  

• There is also another command called cordorn. Cordorn simply marks a node unschedulable. Unlike drain it does not terminate or move the pods on an existing node.

  

K8s Reference Docs

• https://kubernetes.io/docs/tasks/administer-cluster/safely-drain-node/