adding node exporter, loki, and promtail

prometheus_node_exporter/Dockerfile

@@ -0,0 +1,33 @@
+ARG BUILD_FROM
+# hadolint ignore=DL3006
+FROM $BUILD_FROM
+
+# Set shell
+SHELL ["/bin/bash", "-o", "pipefail", "-c"]
+
+# Setup base system
+ARG \
+  BUILD_ARCH \
+  NODE_EXPORTER_VERSION="1.8.2"
+
+# Copy root filesystem
+COPY rootfs /
+
+# hadolint ignore=DL3003,DL3018
+RUN \
+    apk add --no-cache --update apache2-utils tar \
+    && ARCH="${BUILD_ARCH}" \
+    && if [ "${BUILD_ARCH}" = "aarch64" ]; then ARCH="arm64"; fi \
+    && curl -J -L -o /tmp/node_exporter.tar.gz \
+       "https://github.com/prometheus/node_exporter/releases/download/v${NODE_EXPORTER_VERSION}/node_exporter-${NODE_EXPORTER_VERSION}.linux-${ARCH}.tar.gz" \
+    && cd /tmp \
+    && tar -xzvf node_exporter.tar.gz --strip-components=1 \
+    && mv node_exporter /usr/local/bin/ \
+    && adduser -s /bin/false -D -H prometheus \
+    && chown -R prometheus:prometheus /usr/local/bin/node_exporter \
+    && rm -rf /tmp/node_exporter* LICENSE NOTICE
+
+# This add-on runs on the host pid namespace, making it impossible
+# to use S6-Overlay. Therefore the init system is disabled at this point.
+ENTRYPOINT []
+CMD ["/run.sh"]