add docker file for build

docker/Dockerfile

@@ -0,0 +1,54 @@
+# Builder
+FROM erlang:25.3.2.8-alpine AS builder
+RUN apk add --update git build-base bsd-compat-headers openssl-dev snappy-dev curl alpine-sdk bash \
+    && git clone -b 1.13.0 https://github.com/vernemq/vernemq \
+    && cd vernemq \
+    && make -j 16 rel
+
+# Executor
+FROM alpine:3.20
+
+COPY --from=builder /vernemq/_build/default/rel /
+
+RUN apk --no-cache --update --available upgrade && \
+    apk add --no-cache ncurses-libs openssl libstdc++ jq curl bash snappy-dev && \
+    addgroup --gid 10000 vernemq && \
+    adduser --uid 10000 -H -D -G vernemq -h /vernemq vernemq && \
+    install -d -o vernemq -g vernemq /vernemq
+
+# Defaults
+ENV DOCKER_VERNEMQ_KUBERNETES_LABEL_SELECTOR="app=vernemq" \
+    DOCKER_VERNEMQ_LOG__CONSOLE=console \
+    PATH="/vernemq/bin:$PATH" \
+    VERNEMQ_VERSION="2.0.1"
+
+WORKDIR /vernemq
+
+COPY --chown=10000:10000 bin/vernemq.sh /usr/sbin/start_vernemq
+COPY --chown=10000:10000 bin/join_cluster.sh /usr/sbin/join_cluster
+COPY --chown=10000:10000 files/vm.args /vernemq/etc/vm.args
+
+RUN chown -R 10000:10000 /vernemq && \
+    ln -s /vernemq/etc /etc/vernemq && \
+    ln -s /vernemq/data /var/lib/vernemq && \
+    ln -s /vernemq/log /var/log/vernemq
+
+# Ports
+# 1883  MQTT
+# 8883  MQTT/SSL
+# 8080  MQTT WebSockets
+# 44053 VerneMQ Message Distribution
+# 4369  EPMD - Erlang Port Mapper Daemon
+# 8888  Health, API, Prometheus Metrics
+# 9100 9101 9102 9103 9104 9105 9106 9107 9108 9109  Specific Distributed Erlang Port Range
+
+EXPOSE 1883 8883 8080 44053 4369 8888 \
+       9100 9101 9102 9103 9104 9105 9106 9107 9108 9109
+
+
+VOLUME ["/vernemq/log", "/vernemq/data", "/vernemq/etc"]
+
+HEALTHCHECK CMD vernemq ping | grep -q pong
+
+USER vernemq
+CMD ["start_vernemq"]

docker/bin/join_cluster.sh

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+#!/usr/bin/env bash
+
+SECRETS_KUBERNETES_DIR="/var/run/secrets/kubernetes.io/serviceaccount"
+DOCKER_VERNEMQ_KUBERNETES_CLUSTER_NAME=${DOCKER_VERNEMQ_KUBERNETES_CLUSTER_NAME:-cluster.local}
+
+if [ -d "${SECRETS_KUBERNETES_DIR}" ] ; then
+    # Let's get the namespace if it isn't set
+    DOCKER_VERNEMQ_KUBERNETES_NAMESPACE=${DOCKER_VERNEMQ_KUBERNETES_NAMESPACE:-$(cat "${SECRETS_KUBERNETES_DIR}/namespace")}
+fi
+
+insecure=""
+if env | grep "DOCKER_VERNEMQ_KUBERNETES_INSECURE" -q; then
+    echo "Using curl with \"--insecure\" argument to access kubernetes API without matching SSL certificate"
+    insecure="--insecure"
+fi
+
+function k8sCurlGet () {
+    local urlPath=$1
+
+    local hostname="kubernetes.default.svc.${DOCKER_VERNEMQ_KUBERNETES_CLUSTER_NAME}"
+    local certsFile="${SECRETS_KUBERNETES_DIR}/ca.crt"
+    local token=$(cat ${SECRETS_KUBERNETES_DIR}/token)
+    local header="Authorization: Bearer ${token}"
+    local url="https://${hostname}/${urlPath}"
+
+    curl -sS ${insecure} --cacert ${certsFile} -H "${header}" ${url} \
+      || ( echo "### Error on accessing URL ${url}" )
+}
+
+try_join() {
+  local exit_code=0
+  if env | grep "DOCKER_VERNEMQ_DISCOVERY_KUBERNETES" -q; then
+      # Let's set our nodename correctly
+      # https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.19/#list-pod-v1-core
+      podList=$(k8sCurlGet "api/v1/namespaces/${DOCKER_VERNEMQ_KUBERNETES_NAMESPACE}/pods?labelSelector=${DOCKER_VERNEMQ_KUBERNETES_LABEL_SELECTOR}")
+      kube_pod_names=$(echo ${podList} | jq '.items[].spec.hostname' | sed 's/"//g' | tr '\n' ' ' | sed 's/ *$//')
+      VERNEMQ_KUBERNETES_SUBDOMAIN=${DOCKER_VERNEMQ_KUBERNETES_SUBDOMAIN:-$(echo ${podList} | jq '.items[0].spec.subdomain' | tr '\n' '"' | sed 's/"//g')}
+
+      for kube_pod_name in $kube_pod_names; do
+          if [[ $kube_pod_name == "null" ]]; then
+              echo "Kubernetes discovery selected, but no pods found. Maybe we're the first?"
+              echo "Anyway, we won't attempt to join any cluster."
+              exit 0
+          fi
+
+          if [[ $kube_pod_name != "$MY_POD_NAME" ]]; then
+              discoveryHostname="${kube_pod_name}.${VERNEMQ_KUBERNETES_SUBDOMAIN}.${DOCKER_VERNEMQ_KUBERNETES_NAMESPACE}.svc.${DOCKER_VERNEMQ_KUBERNETES_CLUSTER_NAME}"
+              echo "Will join an existing Kubernetes cluster with discovery node at ${discoveryHostname}"
+              vmq-admin cluster show | grep "VerneMQ@${discoveryHostname}" > /dev/null || exit_code=$?
+              if [ $exit_code -eq 0 ]; then
+                  echo "We have already joined the cluster - no extra work required."
+                  exit 0
+              else
+                  echo "We have yet to join the cluster - attempting manual join..."
+                  vmq-admin cluster join discovery-node="VerneMQ@${discoveryHostname}"
+                  sleep 2
+              fi
+              break
+          fi
+      done
+  else
+      exit 0
+  fi
+}
+
+while true
+do
+    try_join
+done;