What is Opkg?
Opkg is the package management system used on embedded Linux systems, most notably OpenWrt. It was designed to replace the Rpm Package Manager (RPM), Debain packages, Alien packages, and the Red Hat Package Manager (RPM), but it can be used with any Linux distribution. With opkg you can easily download and install software packages from the Internet to keep your router up to date without a lot of hassle.
What is Ubuntu?
Ubuntu is a Linux-based operating system that runs from the desktop, to the cloud, to all your internet connected things in between. Perfect for home users, students and hackers alike, its easy-to-use interface puts you in control of your machine. Users can run Ubuntu on a computer, or in a virtual machine on top of their existing operating system. There are three editions: 'Ubuntu Desktop Edition' for personal computers, the 'Ubuntu Server Edition', and the lightweight 'Ubuntu Core' edition for embedded devices and appliances.
Publish Ubuntu packages on Opkg with packagecloud
If you’re looking to publish Ubuntu packages on Opkg, you can use packagecloud to handle all of your package management. Packagecloud works with all kinds of packages, not only Ubuntu packages. With packagecloud you can manage all of your packages from various OS’s, languages, and more. Always trust that your packages will be secure when you publish your Ubuntu packages on Opkg via packagecloud.
Opkg also integrates with

Archlinux

CentOS

Debian

Fedora

Gentoo

Java

Javascript

Kubuntu

Lubuntu

Manjaro

OpenSUSE

Python

Red Hat

Red Hat Enterprise Linux

Ruby

Slackware

SuSe

Xubuntu

Archlinux

CentOS

Debian

Fedora

Gentoo

Java

Javascript

Kubuntu

Lubuntu

Manjaro

OpenSUSE

Python

Red Hat Enterprise Linux

Red Hat

Ruby

Slackware

SuSe

Ubuntu

Xubuntu