first

.gitlab-ci.yml

+stages:
+  - build
+  - deploy
+
+variables:
+  GIT_DEPTH: "1"
+  CONTAINER_TEST_IMAGE: $CI_REGISTRY_IMAGE:$CI_COMMIT_REF_SLUG
+  CONTAINER_RELEASE_IMAGE: $CI_REGISTRY_IMAGE:latest
+
+before_script:
+  - docker login -u $CI_REGISTRY_USER -p $CI_REGISTRY_PASSWORD $CI_REGISTRY
+
+build:
+  stage: build
+  tags: 
+    - docker
+  script:
+    - docker build --pull -t $CONTAINER_TEST_IMAGE .
+    - docker push $CONTAINER_TEST_IMAGE
+
+deploy_latest:
+  stage: deploy
+  tags: 
+    - docker
+  script:
+    - docker pull $CONTAINER_TEST_IMAGE
+    - docker tag $CONTAINER_TEST_IMAGE $CONTAINER_RELEASE_IMAGE
+    - docker push $CONTAINER_RELEASE_IMAGE
+  only:
+    - master
+
+deploy_tag:
+  stage: deploy
+  tags: 
+    - docker
+  variables:
+    CONTAINER_TAG_IMAGE: $CI_REGISTRY_IMAGE:$CI_COMMIT_TAG
+  script:
+    - docker pull $CONTAINER_TEST_IMAGE
+    - docker tag $CONTAINER_TEST_IMAGE $CONTAINER_TAG_IMAGE
+    - docker push $CONTAINER_TAG_IMAGE
+  only:
+    - tags

Dockerfile

+FROM debian:buster-slim
+RUN apt update && \
+    env DEBIAN_FRONTEND=noninteractive apt install -y wide-dhcpv6-client gettext-base && \
+    rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
+
+RUN mkdir -p /usr/src/app
+
+COPY ./dhcp6c.conf.template /usr/src/app/
+COPY ./entrypoint.sh /usr/src/app/
+
+ENV WAN_INTERFACE ppp0
+ENV LAN_INTERFACE ens192
+
+ENTRYPOINT [ "/usr/src/app/entrypoint.sh" ]
+CMD ["bash", "-c", "/usr/sbin/dhcp6c -f -d -c /etc/wide-dhcpv6/dhcp6c.conf -Pdefault $WAN_INTERFACE" ]

README.md

 # docker-dhcpv6-client
 
-Dockerlized wide-dhcpv6-client
\ No newline at end of file
+Dockerlized wide-dhcpv6-client
+
+## Variables
+
+* `WAN_INTERFACE` The interface for Internet, or the interface sending DHCPv6 requests.
+
+* `LAN_INTERFACE` The interface for LAN. If more than one please run multiple containers.

dhcp6c.conf.template

+profile default
+{
+  send ia-pd 0;
+};
+
+id-assoc pd 0 {
+  # use the interface connected to your LAN
+  prefix-interface $LAN_INTERFACE {
+    sla-id 1;
+    sla-len 4;
+  };
+};

entrypoint.sh

+#!/bin/bash
+cat /usr/src/app/dhcp6c.conf.template | envsubst > /etc/wide-dhcpv6/dhcp6c.conf
+
+"$@"