Constant name mismatch (hostIP vs. HOST_IP)

[eitanby]

Exercise
At the start of chapter 9 (the second 'TRY IT NOW')

Problem
in the 'TRY IT NOW' section the reader asked to define a constant named $hostIP but the docker compose file in this chapter use ${HOST_IP}, this cause for prometheus not be able to read metrics from the Docker engine.

Docker version
Client:
Cloud integration: v1.0.24
Version: 20.10.14
API version: 1.41
Go version: go1.16.15
Git commit: a224086
Built: Thu Mar 24 01:53:11 2022
OS/Arch: windows/amd64
Context: default
Experimental: true

Server: Docker Desktop 4.8.1 (78998)
Engine:
Version: 20.10.14
API version: 1.41 (minimum version 1.12)
Go version: go1.16.15
Git commit: 87a90dc
Built: Thu Mar 24 01:46:14 2022
OS/Arch: linux/amd64
Experimental: true
containerd:
Version: 1.5.11
GitCommit: 3df54a852345ae127d1fa3092b95168e4a88e2f8
runc:
Version: 1.0.3
GitCommit: v1.0.3-0-gf46b6ba
docker-init:
Version: 0.19.0
GitCommit: de40ad0

Code version
commit 71384f8

Additional context
I am using Powershell on Windows 10 OS