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Manually Downloading Container Images (Docker, Github Packages)

This article will describe how to download an image from a (docker) container registry.

Intro

Remember the good ‘ol days when you could just download software by visiting a website and click “download”?

Even apt and yum repositories were just simple HTTP servers that you could just curl (or wget) from. Using the package manager was, of course, more secure and convenient — but you could always just download packages manually, if you wanted.

But have you ever tried to curl an image from a container registry, such as docker? Well friends, I have tried. And I have the scars to prove it.

It was a remarkably complex process that took me weeks to figure-out. Lucky you, this article will break it down.

Examples

Specifically, we’ll look at how to download files from two OCI registries.

Docker Hub GitHub Packages Terms

First, here’s some terminology used by OCI

OCI – Open Container Initiative blob – A “blob” in the OCI spec just means a file manifest – A “manifest” in the OCI spec means a list of files Prerequisites

This guide was written in 2024, and it uses the following software and versions:

debian 12 (bookworm) curl 7.88.1 OCI
. . . → Read More: Manually Downloading Container Images (Docker, Github Packages)

Package Manager Search Commands

In a given week, I touch maybe a half dozen different Operating Systems/Distributions. Some are similar to others (centos, rhel), some–not so much (solaris). The common commands are easy enough to remember ( @ls@ vs @dir@ ), but I always forget how to search through each OS’s package manager for a software package. For my reference (and perhaps yours?) here’s a list for each of the OSs’ package managers I use frequently:

yum – RHEL/CentOS

yum list

apt – Debian/Ubuntu

apt-cache search

pacman – Arch

pacman –sync –search pacman -Ss

portage – Gentoo

emerge –search # pkg names only emerge –searchdesc # pkg names & descriptions emerge -S # alias of –searchdesc  

See Also: “Install ‘build-essential’ on RHEL/CentOS and OpenSolaris”:/wp/?p=231

Michael Altfield

Hi, I’m Michael Altfield. I write articles about opsec, privacy, and devops ➡

About Michael

tech.michaelaltfield.net/