Update kubeadm-upgrade.md (#17407)

Sometimes, pods like `coredns` only run on the master nodes. If there is a problem with upgrading the master node (e.g. if it is interrupted) those pods will not keep running - and other pods will have problems with connections. Draining the master node will switch those pods to other nodes before the upgrade-process.
2019-11-04 23:12:12 +01:00
parent 9d21f9c105
commit 24edeac0b4
1 changed files with 12 additions and 0 deletions
@@ -88,6 +88,12 @@ The upgrade workflow at high level is the following:
    kubeadm version
    ```

+1.  Drain the control plane node:
+
+    ```shell
+    kubectl drain $MASTER --ignore-daemonsets
+    ```
+
 1.  On the control plane node, run:

    ```shell
@@ -231,6 +237,12 @@ The upgrade workflow at high level is the following:

    This step is not required on additional control plane nodes if the CNI provider runs as a DaemonSet.

+1.  Uncordon the control plane node
+
+    ```shell
+    kubectl uncordon $MASTER
+    ```
+
 ### Upgrade additional control plane nodes

 1.  Same as the first control plane node but use: