This article describes the limitations on using Nova in an offline environment where a Nova device cannot reach the Internet. In general, Nova is designed for just such installations, but when using the SDK functionality, care must be taken when performing certain configuration changes and upgrades.
The SDK Build Process.
Nova’s SDK container is based upon the Alpine image bundled with the Nova distribution, and can thus be started without any Internet access. But if you use the SDK configuration to add packages to the container (including installing Docker by enabling containers within the SDK) each of these packages must be downloaded from online repositories. This means that when these packages are first added, the device must reach out to the Internet to obtain the appropriate images. If the device is offline, the packages cannot be deployed.
Further, if you install an updated version of Nova that contains a different Alpine base image, the build process must be repeated in order to add these packages on top of the updated Alpine image. If the Internet is not available, versions before R4-0063 will simply not start the SDK container, while later versions will continue to use the old image until the source repositories can be reached. For older versions, it is thus important that the Internet is available after an update if the SDK is being used.
The Container Build Process
Containers within the SDK typically need Internet access to download their initial image. Unless you have the Always Pull Image option selected, online access is not needed upon an update to Nova, even if the base Alpine image has changed. Containers, however, may need their own online access. Node-RED for example needs access to the npm repositories in order to install new nodes. Most containers can operate offline quite happy once they have been configured, but you should take care during the configuration process, especially when adding plugins or similar expansion modules.
Using the Vantage Proxy
The Vantage Device Manager can act as an Internet proxy for devices inside a closed network, assuming that the Vantage installation can itself see the Internet. To enable this, configure the server to indicate that the devices are blocked from reaching the Internet. This will instruct the devices to use Vantage as a secure proxy for operations such as package installation, etc.
By default, only known URLs will be allowed through, allowing access to the Alpine, Docker and npm repositories. Additional URLs can be added, or the URL filter can be disabled entirely. The proxy configuration is injected into each SDK container using well-known environment variables that most containers will honor. We cannot guarantee, however, that any particular container will be compatible.
