Hardware Event Proxy

In a baremetal cloud environment, applications may need to be able to act upon hardware changes and failures quickly to achieve high reliability. Hardware Event Proxy provides a way for such applications to subscribe and receive Redfish hardware events with low-latency.

Hardware Event Proxy subscribes to Redfish Events of the target hardware and creates publishers for the events using Cloud Event Proxy framework. Users/Applications can subscibe to the events using the APIs provided by Cloud Event Proxy.

How It Works

Hardware Event Proxy contains a main hw-event-proxy module written in Go and a message-parser module written in Python.

The message-parser module is used to parse messages from Redfish Event Message Registry. At startup, it queries the Redfish API and downloads all the Message Registries (if not already included in Sushy library) including custom registries.

Once subscribed, Redfish events can be received by the webhook located in the hw-event-proxy module. If the event received does not contain a Message field, hw-event-proxy will send a request with MessageId to message-parser. Message Parser uses the MessageId to search in the Message Registries and find the Message and Resolution and pass them back to hw-event-proxy. hw-event-proxy adds these fields to the event content and converts the event to Cloud Event and sends it out to Cloud Event Proxy framework.

Event Subscription to BMC

Hardware Event Proxy subscribes to Redfish Events by sending a subscription request to the baseboard management controller (BMC) of the target hardware. The request should include the webhook URL of Hardware Event Proxy as the destination address. A perfered way of subscription is via BMCEventSubscription CRD.

Example:

apiVersion: metal3.io/v1alpha1
kind: BMCEventSubscription
metadata:
  name: sub-01
  namespace: some-namespace
spec:
   hostName: baremetal-host-name
   destination: https://events.apps.corp.example.com/webhook
   context: “SomeUserContext”

The baremetal-host-name can be found from the following command. It is the host where target BMC is located.

oc -n openshift-machine-api get bmh

Subscribe to Hardware Event Proxy

Create Subscription with JSON Example

Request

{
  "Resource": "/cluster/node/nodename/redfish/event",
  "UriLocation”: “http://localhost:9089/event"
}

Response

{
  "ID": "da42fb86-819e-47c5-84a3-5512d5a3c732",
  "Resource": "/cluster/node/nodename/redfish/event",
  "endpointURI": "http://127.0.0.1:9089/event",
  "URILocation": "http://localhost:8089/api/cloudNotifications/v1/subscriptions/da42fb86-819e-47c5-84a3-5512d5a3c732"
}

Create Subscription with Golang Example

package main

import (
    v1pubsub "github.com/redhat-cne/sdk-go/v1/pubsub"
    v1amqp "github.com/redhat-cne/sdk-go/v1/amqp"
    "github.com/redhat-cne/sdk-go/pkg/types"
)

func main(){
    nodeName := os.Getenv("NODE_NAME")
    resourceAddressHwEvent := fmt.Sprintf("/cluster/node/%s/redfish/event", nodeName)

    //channel for the transport handler subscribed to get and set events  
    eventInCh := make(chan *channel.DataChan, 10)       
    pubSubInstance = v1pubsub.GetAPIInstance(".")
    endpointURL := &types.URI{URL: url.URL{Scheme: "http", Host: "localhost:8089", Path: fmt.Sprintf("%s%s", apiPath, "dummy")}}

    // create subscription
    pub, err := pubSubInstance.CreateSubscription(v1pubsub.NewPubSub(endpointURL, resourceAddressHwEvent))
    // once the subscription response is received, create a transport listener object to receive events.
    if err==nil{
        v1amqp.CreateListener(eventInCh, pub.GetResource())
    }
}

A complete example of consumer implementation is avialble at Cloud Event Proxy repo.

Developer Guide

Instructions for development and tests are available at Developer Guide.