diff --git a/prepare-vms/lib/commands.sh b/prepare-vms/lib/commands.sh
index ba4aed747..dcd499f7c 100644
--- a/prepare-vms/lib/commands.sh
+++ b/prepare-vms/lib/commands.sh
@@ -239,6 +239,14 @@ _cmd_docker() {
       sudo ln -sfn /mnt/docker /var/lib/docker
     fi
 
+    # containerd 1.6 breaks Weave.
+    # See https://github.com/containerd/containerd/issues/6921
+    sudo tee /etc/apt/preferences.d/containerd <<EOF
+Package: containerd.io
+Pin: version 1.5.*
+Pin-Priority: 1000
+EOF
+
     # This will install the latest Docker.
     sudo apt-get -qy install apt-transport-https ca-certificates curl software-properties-common
     curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -