Add ARM64 Docker images for Prom/AlertManager

Signed-off-by: Alex Ellis <alexellis2@gmail.com>

contrib/alertmanager-arm64/0.16.1/Dockerfile

+FROM alpine:3.9
+
+WORKDIR /root
+RUN apk add --update libarchive-tools
+ADD https://github.com/prometheus/alertmanager/releases/download/v0.16.1/alertmanager-0.16.1.linux-arm64.tar.gz /root/
+RUN bsdtar -xvf *.tar.gz -C ./ --strip-components=1
+RUN mkdir /etc/alertmanager
+
+RUN cp alertmanager               /bin/alertmanager
+RUN cp alertmanager.yml           /etc/alertmanager/alertmanager.yml
+
+EXPOSE     9093
+VOLUME     [ "/alertmanager" ]
+WORKDIR    /alertmanager
+
+ENTRYPOINT [ "/bin/alertmanager" ]
+CMD        [ "--config.file=/etc/alertmanager/alertmanager.yml", \
+    "--storage.path=/alertmanager" ]

contrib/alertmanager-arm64/0.16.1/Makefile

+.PHONY: all
+all: ci-arm64-build ci-arm64-push
+
+.PHONY: ci-arm64-build
+ci-arm64-build:
+	docker build -t functions/alertmanager:0.16.1-arm64 .
+
+.PHONY: ci-arm64-push
+ci-arm64-push:
+	docker push functions/alertmanager:0.16.1-arm64

contrib/alertmanager-arm64/0.16.1/README.md

+# Alertmanager for ARM64
+
+## Building:
+
+```bash
+make ci-arm64-build
+```
+
+## Pushing:
+
+```bash
+make ci-arm64-push
+```

contrib/prometheus-arm64/2.7.1/Dockerfile

+FROM alpine:3.9
+WORKDIR /root/
+
+RUN apk add --update libarchive-tools curl \
+    && curl -sLf https://github.com/prometheus/prometheus/releases/download/v2.7.1/prometheus-2.7.1.linux-arm64.tar.gz > prometheus.tar.gz \
+    && bsdtar -xvf prometheus.tar.gz -C ./ --strip-components=1 \
+    && apk del libarchive-tools curl \
+    && mkdir /etc/prometheus \
+    && mkdir -p /usr/share/prometheus \
+    && cp prometheus                             /bin/prometheus \
+    && cp promtool                               /bin/promtool \
+    && cp prometheus.yml  				/etc/prometheus/ \
+    && cp -r console_libraries                     /usr/share/prometheus/ \
+    && cp -r consoles                              /usr/share/prometheus/ \
+    && rm -rf /root/*
+
+RUN ln -s /usr/share/prometheus/console_libraries /usr/share/prometheus/consoles/ /etc/prometheus/
+RUN mkdir -p /prometheus && \
+    chown -R nobody:nogroup /etc/prometheus /prometheus
+
+USER       nobody
+EXPOSE     9090
+VOLUME     [ "/prometheus" ]
+WORKDIR    /prometheus
+
+ENTRYPOINT [ "/bin/prometheus" ]
+CMD        [ "--config.file=/etc/prometheus/prometheus.yml", \
+    "--storage.tsdb.path=/prometheus", \
+    "--web.console.libraries=/usr/share/prometheus/console_libraries", \
+    "--web.console.templates=/usr/share/prometheus/consoles" ]
+

contrib/prometheus-arm64/2.7.1/Makefile

+.PHONY: all
+all: ci-arm64-build ci-arm64-push
+
+.PHONY: ci-arm64-build
+ci-arm64-build:
+	docker build -t functions/prometheus:2.7.1-arm64 .
+
+.PHONY: ci-arm64-push
+ci-arm64-push:
+	docker push functions/prometheus:2.7.1-arm64
+

contrib/prometheus-arm64/2.7.1/README.md

+# Prometheus for ARM64
+
+## Building:
+
+```bash
+make ci-arm64-build
+```
+
+## Pushing:
+
+```bash
+make ci-arm64-push
+```