Login in https://www.dynu.com/en-US/ and get your ddns domain.
docker run
docker run -d --restart=always --name dynu-client \
-e MY_HOSTNAME=$ddns_domain \
-e MY_USER=$user \
-e MY_PASS=$secret \
wcen/docker-dynu-client:latest
parameters
MY_HOSTNAME: ddns domain
MY_USER: dynu login user (usally e-mail or account)
MY_PASS: can use encryption password