I am building a new Docker image with:
FROM alpine:3.4
RUN apk upgrade --update
However, its failing with the error:
[INFO]         
        I ran into something like this.  It completely blew my mind, and I was questioning my sanity for a bit until I realized that /sbin wasn't in my container's PATH.
If you type command -v apk in an interactive session in your container's base image and compare that directory with the container's $PATH that should get you squared away.
If command -v apk doesn't work for you, you could try to find it via
find / -name apk -type f -exec dirname "{}" ";"
To the best of my knowledge this is always in /sbin. However you get there, just ensure that the apk binary's location is part of $PATH
In the end we upgraded our projects to use this Docker Maven plugin: https://github.com/fabric8io/fabric8-maven-plugin. No issue thus far.