Add note on node cordon and draining for upgrades

Signed-off-by: Faraz Khawaja <khwajafarazahmed@gmail.com>

Author: farazkhawaja

docs/upgrades/manual.md

@@ -42,6 +42,10 @@ Running the install script will:
 2. Update the systemd unit or openrc init script to reflect the args passed to the install script
 3. Restart the k3s service
 
+:::note
+Containers for Pods continue running even when K3s is stopped. The install script does not drain or cordon the node before restarting k3s. If your workload is sensitive to brief API server outages, you should manually [drain and cordon](https://kubernetes.io/docs/reference/kubectl/generated/kubectl_drain/) the node using `kubectl` before re-running the install script to upgrade k3s or modify the configuration, and uncordon it afterwards.
+:::
+
 For example, to upgrade to the current stable release:
 
 ```sh
@@ -70,3 +74,7 @@ To upgrade K3s manually, you can download the desired version of the K3s binary
 1. Download the desired version of the K3s binary from [releases](https://github.com/k3s-io/k3s/releases)
 2. Copy the downloaded binary to `/usr/local/bin/k3s` (or your desired location)
 3. Restart the k3s or k3s-agent service or restart the k3s process (binary)
+
+:::note
+Containers for Pods continue running even when K3s is stopped. It is generally safe to restart K3s without draining pods and cordoning the node. If your workload is sensitive to brief API server outages, you should manually [drain and cordon](https://kubernetes.io/docs/reference/kubectl/generated/kubectl_drain/) the node using `kubectl` before restarting K3s, and uncordon it afterwards.
+:::