Merge pull request #387 from ErvinRacz/patch-3

Update managing-updates.md with Nebraska hosted packages

content/docs/latest/nebraska/managing-updates.md

@@ -104,6 +104,26 @@ This functionality is turned off by default. So to make Nebraska host the Flatca
 
     nebraska -host-flatcar-packages=true -flatcar-packages-path=/PATH/TO/STORE/PACKAGES -nebraska-url=http://your.Nebraska.host:port
 
+#### Hosting without synchronization
+
+You can use Nebraska to host and serve the packages entirely without synchronization. This can be useful for example if you have an isolated environment without internet access (e.g air-gapped environment)
+
+The steps to achieve this are the following:
+
+ 1. Create a dedicated directory on the Nebraska server to store the packages: `/PATH/TO/STORE/PACKAGES`
+ 2. You can find the official packages here: https://update.release.flatcar-linux.net
+ 3. Download/Upload the packages you want to server to that folder: `wget -o- https://update.release.flatcar-linux.net/{{architecture}}-usr/{{version}}/flatcar_production_update.gz` or alternatively `cp /media/usb/flatcar_production_update.gz /PATH/TO/STORE/PACKAGES/`.
+ 4. Start your nebraska instance with the following options `nebraska -host-flatcar-packages=true -flatcar-packages-path=/PATH/TO/STORE/PACKAGES -nebraska-url=http://your.Nebraska.host:port`
+ 5. Register the new package in Nebraska too. Go to your application > Add Package > Fill the form, where the `URL` and the `filename` should match with the options you provided earlier
+    For example, if your ip address is `172.31.239.34`, and if the dedicated directory to store the packages is: `/tmp/flatcar/`, while the package is in the subdir `/tmp/flatcar/4230.0.0`, you start nebraska with the following params: `-host-flatcar-packages=true`, `-flatcar-packages-path=/tmp/flatcar`, and `-nebraska-url=http://172.31.239.34:8000`, then the filled form should look like:
+
+<p align="center">
+  <img width="100%"  src="./images/nebraska-hosts-packages.png">
+</p>
+
+ 6. Assign the newly added package to your channel
+ 7. Watch your flatcar nodes getting updates with the selfhosted package
+
 ### Overriding synchronized packages' URLs
 
 Some users may choose to host their own packages elsewhere (i.e. without using the