**Problem:**
- Cannot set up kubelet on Windows
- Sometimes, host kubelet cannot connect controlplanes via container nginx proxy, but we found that only the connection between kubelet and container nginx has been broken.
- Upgraded from previous existing cluster causes Windows agent failed
- Running a few days, Windows host will crash by OOM, as `docker create
-> docker start` leaks none-page memory
- The Windows code doesn't look very clear
- Need to support Flannel vxlan mode
- Need to support CI
- Need to support Docker manifest images
- Need to add unit test

**Solution:**
- Adjust kubelet options
- Replace container Nginx proxy by host Nginx
- Fix Windows error when upgrading rancher
    + Use `AllK8sWindowsVersions` to index system images
    + Specify the `NetworkMode` of Process to `none`
- For Windows, replace `docker create -> docker start` to `docker run`
- Refactor Windows agent
    + Separate logrus hook into a file
    + Create `winRunner` to execute main logic
    + Rem...