Health Monitor design doc (hitachienergy#940)

* Fixed line endings for devcontainer

* Requirements for Health Monitor app

core/src/epicli/.devcontainer/cert/config-pre.sh

@@ -1,4 +1,5 @@
 #!/bin/bash
+
 if ls /usr/local/share/ca-certificates/*.crt 1> /dev/null 2>&1; then
   echo "Setup cert for System, PIP..."
   pattern="/usr/local/share/ca-certificates/*.crt"

docs/design-docs/health-monitor/health-monitor.md

@@ -0,0 +1,33 @@
+# Epiphany Health Monitor service design proposal
+
+Affected version: 0.6.x/0.7.x
+
+## Goals
+
+Provide service that will be monitoring components (Kubernetes, Docker, Kafka, EFK, Prometheus, etc.) deployed using Epiphany.
+
+## Use cases
+
+Service will be installed and used on Virtual Machines/Bare Metal on Ubuntu and RedHat (systemd service).
+Health Monitor will check status of components that were installed on the cluster. Combinations of those components can be different and will be provided to the service through configuration file.
+
+Components that Health Monitor should check:
+- Kubernetes (kubelet)*
+- Query Kubernetes health endpoint (/healthz)*
+- Docker*
+- Query Docker stats*
+- PostgreSQL
+- HAProxy
+- Prometheus
+- Kafka
+- ZooKeeper
+- ElasticSearch
+- RabbitMQ
+
+`*` means MVP version.
+
+Health Monitor exposes endpoint that is compliant with [Prometheus metrics format](https://github.com/prometheus/docs/blob/master/content/docs/instrumenting/exposition_formats.md#text-format-example) and serves data about health checks. This endpoint should listen on the configurable port (default 98XX).
+
+## Design proposal
+
+TODO