Docker on Raspbian 64 bit with arm64v8 image

Hello?

You need to install Raspberry Pi OS 64-bit version.

I also installed stable version(32-bit) and upgraded. the kernel is 64-bit but system still 32-bit (at least package manager still use 32-bit binary: dpkg --print-architecture).
I think rpi-update didn’t upgrade whole system.

I downloaded/installed 64-bit version OS from raspios_arm64.
And, followed the guide how to install Docker engine on Debian.

Server: Docker Engine - Community
 Engine:
  Version:          20.10.7
  API version:      1.41 (minimum version 1.12)
  Go version:       go1.13.15
  Git commit:       b0f5bc3
  Built:            Wed Jun  2 11:55:56 2021
  OS/Arch:          linux/arm64
  Experimental:     false