Why are Docker build commands running so slow in Elastic Beanstalk?

Question

EB was complaining that my build was timing out, so I ssh'd into an instance and decided to run docker build myself to see what was happening. Every step, even something as simple as a mkdir takes ages to run. Even a WORKDIR stalls for at least a minute or two before executing.

On my local machine these are instant. What is going on?

Answer 1

Same issue here with an Ubuntu machine running on AWS. Turns out the the key to the solution was switching from devicemapper to aufs storage backend.

First, run the following command to figure out which storage backend your currently use:

docker info | grep Storage

If it says devicemapper, you probably found the reason for the slowness.

Here is the prodecure for switching to the aufs backend in Ubuntu, taken from here:

1. sudo apt-get install -y -q linux-image-extra-$(uname -r)
2. sudo service docker restart

Note that you will have to rebuild all your existing images / containers, as they will be wiped when you switch to aufs.