So I solved the problem. The pinata tool allows you to configure the daemon. Here’s the config options: https://docs.docker.com/engine/reference/commandline/daemon/#daemon-configuration-file
You can get your current config options like this:
$ pinata get daemon > myconfig.json
… make changes (in this case, adding “dns-search”: [“company.net”]), and upload the config to pinata with:
$ pinata set daemon @myconfig.json