FYI 20.10 is not found/supported anymore, here is the output of multipass find

$ multipass find
Image                       Aliases           Version          Description
snapcraft:core18                              20201111         Snapcraft builder for Core 18
snapcraft:core20                              20210921         Snapcraft builder for Core 20
snapcraft:core                                20210929         Snapcraft builder for Core 16
18.04                       bionic            20210928         Ubuntu 18.04 LTS
20.04                       focal,lts         20211015         Ubuntu 20.04 LTS
21.04                       hirsute           20211017         Ubuntu 21.04
anbox-cloud-appliance                         latest           Anbox Cloud Appliance
minikube                                      latest           minikube is local Kubernetes

Thanks @jaime 👍 I've changed to the following which seems to work:

-multipass launch -c 2 -m 2G -d 4G -n docker 20.10 --cloud-init -
+multipass launch -c 2 -m 2G -d 4G -n docker 20.04 --cloud-init -

FWIW, k3d commands failed for me with:

> k3d cluster list
...
ERRO[0000] Failed Cluster Preparation: Failed Network Preparation: unable to parse docker host `docker.local`

I fixed by:

1. Getting the VM IP

   > multipass list
   Name                    State             IPv4             Image
   docker                  Running           192.168.64.2     Ubuntu 20.04 LTS

2. Setting the DOCKER_HOST explicitly to this IP

   > export DOCKER_HOST=tcp://192.168.64.2:2375
   
   > k3d cluster list
   NAME              SERVERS   AGENTS   LOADBALANCER
   gdk-cluster-ado   1/1       0/0      true