Below you can find environment variables you can set while using this tool.
Default value: 600
Specifies time (in seconds) to wait for the Docker daemon to prepare a response to an API call we make. In most cases this is not important, but you may consider to bump this value if your Docker engine is busy.
Most resource consuming call is exporting the image tar from daemon. If you build parallel some images and/or export more images at the same time — Docker can fail to prepare the archive in time and you’ll see a timeout. This squash tool will retry (3 times) to fetch it, but sometimes you want to make the timeout a bit higher.
Default value: unix://var/run/docker.sock
Connection string to the Docker daemon. You will not be required to change this if
you use default installation of Docker, which creates the socket at /var/run/docker.sock.
If you do use custom Docker daemon settings or connect to a remote Docker daemon — update this environment variable.
Previously it used to be named DOCKER_CONNECTION. This will still work, but
it’s deprecated and will be removed in future releases.
In case you are on OS X or you are connecting to docker via SSL, you should set
DOCKER_HOST, DOCKER_TLS_VERIFY, and DOCKER_CERT_PATH variables properly. If
you're using docker-machine or boot2docker you're all set!