Amend 1.16 kubeadm upgrade guide

There is a common issue when upgrading a cluster to 1.16.x from 1.15.y.
2020-03-31 12:27:24 +08:00
parent 12f0b657ab
commit e568b61cd5
1 changed files with 18 additions and 0 deletions
@@ -237,6 +237,24 @@ 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.

+    One common issue you may encounter if you are using Flannel network is
+    that after the upgrade, the cluster nodes remain in `NotReady` state.
+    If you do `kubectl get nodes -o yaml`, you may see following lines in the
+    output:
+
+    ```
+    message:docker: network plugin is not ready: cni config uninitialized
+    ```
+
+    In this case, you will need to update the `/etc/cni/net.d/10-flannel.conflist`
+    file to include the `cniVersion` line, as shown below:
+
+    ```
+      "name": "cbr0",
+      "cniVersion": "0.2.0",
+      "plugins": [ ...
+    ```
+
 1.  Uncordon the control plane node

    ```shell