* Add limited containerd support
Containerd support for Ubuntu + Calico
* Added CRI-O support for ubuntu
* containerd support.
* Reset containerd support.
* fix lint.
* implemented feedback
* Change task name cri xx instead of cri-o in reset task and timeout condition.
* set crictl to fixed version
* Use docker-ce's container.io package for containerd.
* Add check containerd is installable or not.
* Avoid stop docker when use containerd and optimize retry for reset.
* Add config.toml.
* Fixed containerd for kubelet.env.
* Merge PR #4629
* Remove unused ubuntu variable for containerd
* Polish code for containerd and cri-o
* Refactoring cri socket configuration.
* Configurable conmon.
* Remove unused crictl/runc download
* Now crictl and runc is downloaded by common crictl.yml.
* fixed yamllint error
* Fixed brokenfiles by conflict.
* Remove commented line in config.toml
* Remove readded v1.12.x version
* Fixed broken set_docker_image_facts
* Fix yamllint errors.
* Remove unused apt source
* Fix crictl could not be installed
* Add containerd config from skolekonov's PR #4601
* File and container image downloads are now cached localy, so that repeated vagrant up/down runs do not trigger downloading of those files. This is especially useful on laptops with kubernetes runnig locally on vm's. The total size of the cache, after an ansible run, is currently around 800MB, so bandwidth (=time) savings can be quite significant.
* When download_run_once is false, the default is still not to cache, but setting download_force_cache will still enable caching.
* The local cache location can be set with download_cache_dir and defaults to /tmp/kubernetes_cache
* A local docker instance is no longer required to cache docker images; Images are cached to file. A local docker instance is still required, though, if you wish to download images on localhost.
* Fixed a FIXME, wher the argument was that delegate_to doesn't play nice with omit. That is a correct observation and the fix is to use default(inventory_host) instead of default(omit). See ansible/ansible#26009
* Removed "Register docker images info" task from download_container and set_docker_image_facts because it was faulty and unused.
* Removed redundant when:download.{container,enabled,run_once} conditions from {sync,download}_container.yml
* All features of commit d6fd0d2aca by Timoses <timosesu@gmail.com>, merged May 1st 2019, are included in this patch. Not all code was included verbatim, but each feature of that commit was checked to be working in this patch. One notable change: The actual downloading of the kubeadm images was moved to {download,sync)_container, to enable caching.
Note 1: I considered splitting this patch, but most changes that are not directly related to caching, are a pleasant by-product of implementing the caching code, so splitting would be impractical.
Note 2: I have my doubts about the usefulness of the upload, download and upgrade tags in the download role. Must they remain or can they be removed? If anybody knows, then please speak up.
* Refactor downloads to use download role directly
Also disable fact delegation so download delegate works acros OSes.
* clean up bools and ansible_os_family conditionals
