Step 3/8 taking abnormally long time

When deploying a Meteor 1.6 app using meteor-up 1.3.6, there is an abnormal amount of delay (5-10 minutes) on step 3 of 8:

Finished Extracting
Creating Dockerfile
Finished creating Dockerfile
Building image
Sending build context to Docker daemon  352.3MB
Step 1/8 : FROM abernix/meteord:node-8.4.0-binbuild
 ---> e5c01572b179
Step 2/8 : RUN mkdir /built_app
 ---> Using cache
 ---> c84525bca07f
Step 3/8 : COPY ./ /built_app

The app was originally deployed using the abernix/meteord:base image, but seems to have significantly slower deployment times using the abernix/meteord:node-8.4.0-binbuild image. I am not completely certain that the Docker image is the problem, it just seems strongly correlated.

[zodern]

Mup 1.5 (#976) has a number of performance improvements. Two of them are related to Prepare Bundle:

1. When building the image during Prepare Bundle, it set each environment variable in a separate build instruction in the docker file, which resulted in a new layer for each environment variable. It now sets all of the environment variables in one instruction. One of mup’s tests is 30 seconds faster due to this.
2. The Start Meteor task would wait 15 seconds after creating the docker container before verifying deployment. Since Prepare Bundle helps the app to start faster, the task now only waits 3 seconds when it is enabled.

[zodern]

Version 1.4.5 is now available which adds the option app.docker.stopAppDuringPrepareBundle. When enabled the downtime is only the amount of time it takes to create the docker container and start the app, which can be as low as a few seconds.