change: [M3-8957] - Allow Docker registry to be overridden when build…

…ing Cloud images (linode#11360)

* Allow Docker registry to be overridden via `IMAGE_REGISTRY` arg

* Add changeset

packages/manager/.changeset/pr-11360-tech-stories-1733774598326.md

@@ -0,0 +1,5 @@
+---
+"@linode/manager": Tech Stories
+---
+
+Add `IMAGE_REGISTRY` Docker build argument ([#11360](https://github.com/linode/manager/pull/11360))

packages/manager/Dockerfile

@@ -1,8 +1,12 @@
+# Registry to use when pulling images.
+# Defaults to Docker Hub, but can be overriden to point to another registry if needed.
+ARG IMAGE_REGISTRY=docker.io
+
 # Node.js base image for Cloud Manager CI tasks.
 #
 # Extends from the Node.js base image that corresponds with our latest supported
 # version of Node, and includes other tools that we rely on like pnpm and bun.
-FROM node:20.17-bullseye-slim as nodejs-cloud-manager
+FROM ${IMAGE_REGISTRY}/node:20.17-bullseye-slim as nodejs-cloud-manager
 RUN npm install -g pnpm bun
 
 # `manager`
@@ -28,7 +32,7 @@ CMD yarn start:manager:ci
 #
 # Builds an image containing Cypress and miscellaneous system utilities required
 # by the tests.
-FROM cypress/included:13.11.0 as e2e-build
+FROM ${IMAGE_REGISTRY}/cypress/included:13.11.0 as e2e-build
 RUN npm install -g pnpm bun
 USER node
 WORKDIR /home/node/app