A simple health checker.
Rey will read a json based file with a list of components (applications) to perform health checks. On any status change, rey will expose a gauge metric to prometheus.
All rey configurations are read by environment variables (except for components list, this configuration is read by a json based file on file system)
| Env | Description | Default |
|---|---|---|
| REY_CHECKER_TIMEOUT | http request timeout (in second) | 5 |
| REY_CHECKER_MAX_RETRY | max retry to perform http request on check a component | 3 |
| REY_RUNNER_CIRCLE_INTERVAL | checker interval (in second) | 10 |
| REY_COMPONENTS_PATH | path of components list json based file | /etc/rey/components.json |
| REY_METRICS_SERVER_PORT | Port to listen on Prometheus metrics server | 5000 |
| REY_NOTIFIER_TOKEN | Slack token to perform the notification | |
| REY_NOTIFIER_USERNAME | Slack bot username | Doc. Rey |
| REY_NOTIFIER_AVATAR | Slack bot avatar | https://bit.ly/2Sbf65n |
| REY_NOTIFIER_CHANNEL | Slack channel to send notification |
We strongly recommend you to put all rey stuff in a new kubernetes namespace
$ kubectl create ns rey
For the component list you can create a simple json file with a list of components following those fields
]
{
"name": "<component name>",
"hc_endpoint": "<component healthcheck url>",
}
]And create a kubernetes configmap
$ kubectl create configmap rey-components --from-file=./components.json -n rey
We'll use that configmap to mount a volume with componets file on rey container
Finally you can use the rey-app.yaml template to create a kubernetes deploy and a kubernetes ClusterIP service (to expose prometheus metrics)
$ kubectl create -f rey-app.yaml -n rey
When you deploy rey on your Kubernetes cluster rey will expose simple metrics to Prometheus
with components health status (same as HTTP status of each request and 500 for request errors [e.g. timeouts]).
With these metrics you can create a Grafana dashboard, just use queries like:
rey{componente_name="<name of the component>"}.