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 CentOS?
CentOS Linux is a free and open source operating system that is functionally compatible with its upstream source, Red Hat Enterprise Linux (RHEL). CentOS conforms fully with the upstream vendor's redistribution policy and aims to be 100% binary compatible. It aims to provide enterprise-class capabilities on community-supported infrastructure.
Publish CentOS packages on Opkg with packagecloud
If you’re looking to publish CentOS packages on Opkg, you can use packagecloud to handle all of your package management. Packagecloud works with all kinds of packages, not only CentOS 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 CentOS packages on Opkg via packagecloud.
Opkg also integrates with

Archlinux

Debian

Fedora

Gentoo

Java

Javascript

Kubuntu

Lubuntu

Manjaro

OpenSUSE

Python

Red Hat

Red Hat Enterprise Linux

Ruby

Slackware

SuSe

Ubuntu

Xubuntu

Archlinux

CentOS

Debian

Fedora

Gentoo

Java

Javascript

Kubuntu

Lubuntu

Manjaro

OpenSUSE

Python

Red Hat Enterprise Linux

Red Hat

Ruby

Slackware

SuSe

Ubuntu

Xubuntu