The best replacement for docker is vagrant.

The best alternatives to docker are rated as following:
★★★★★  vagrant
★★★★  lxc
★★★★  chef
★★★  puppet
★★★  openvz
★★  ansible
★★  warden
★★  virtualenv
★★  cloud foundry
★  jails
★  dokku
★  ami
  smartos
  kvm
  zerovm

Your alternative for docker is not listed? Suggest!
Speaking about docker, one probably shouldn't forget about vagrant.

Other search terms related to docker and their ratings are:
★★★★★ vagrant
★★★★ chef
★★★ puppet
★★★ supervisord
★ ansible
★ openstack
★ lxc
You have in mind a companion for docker and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of docker in all years. Click on graph for more.
docker
vagrant
lxc