How to create a UBOS-based appliance running a particular app¶
Imagine you are a developer of an app, and would like to distribute your app pre-installed on a device or boot medium. For example, you might want to hand out SD cards for the Raspberry Pi that have Wordpress installed, so users have to do nothing other than to insert the SD card into their Raspberry Pi and have Wordpress running.
You could, of course, install UBOS on a master SD card, then deploy Wordpress to it with ubos-admin deploy, and distribute binary copies of that master SD card. The trouble with this approach is that all your users will have to use the same secrets: the same database passwords, the same password salts etc. For security reasons, that is not advisable.
To solve this problem, first create a site JSON file that contains the configuration of the app or apps as you would like to see them for all your customers, e.g.:
ubos-admin createsite -n -o site-template.json
Then, edit the created site-template.json and remove instance-specific information, such as:
- the siteid
- each appconfigid
- instance-specific secrets.
To test that this template works as a template, deploy it on a test device:
ubos-admin deploy --template -f site-template.json
Once you are satisfied, copy site-template.json into directory /var/lib/ubos/deploy-site-templates-on-boot/ on the media you would like to hand out. When a device using the media boots, and UBOS finds a valid site template in this directory, it will automatically execute ubos-admin deploy --template as you did above, and deploy the site. Because it deploys from a template, all the secrets and identifiers will be unique to the customer’s device.
Note: it is recommended you make sure all code necessary to deploy the site is available on the device without needing access to the network, otherwise the deploy-on-boot will fail for those customers that boot the device without being connected to the internet.