Starting Docker rancher/rancher with IPV6

I am trying to start the latest docker rancher/rancher in an IPV6 only environment. I see that I need to set an IPV6 --node-ip, --cluster-cidr, and --service-cidr the first time k3s starts up, but how do I pass those values in at runtime? Are there env variables or args passed to the container?
Thanks everyone!

I have tried two different ways to set the cidrs:

  1. pass the IPV6 values as values of the INSTALL_KS3_EXEC argument when running the rancher/rancher container. I can see the environment variable is set inside the running container, but the services and pods appear to have ipv4 addresses

  2. I have tried mapping a config.yaml file to /etc/rancher/k3s/config.yaml. The container exits immediately with a “cannot configure IPv4 cluster-cidr: no IPv4 CIDRs found” . So it would appear that is trying to use the params in the config file, but I am missing something.

Currently I only have
node-ip: [Valid IPV6-IP]
cluster-cidr: [Valid IPV6-CIDR]
service-cidr: [Valid IPV6-CIDR]
disable-network-policy: true

Am I heading in the right direction? Are there additional things for me to tweak or a different way to do it?