HA Cluster Exporter

This snap includes haclusterexporter to provide Pacemaker-based HA cluster
statistics via Prometheus. Grafana dashboards can then be used to visualize
the exported metrics.

How-To
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How to install the snap:

sudo snap install hacluster-exporter

The snap starts haclusterexporter as a daemon automatically and exposes
metrics on :9664/metrics by default.

How to use the service:

Configure Prometheus to scrape http://<cluster-node>:9664/metrics.
For the most complete cluster visibility, run the snap on each cluster node.

The exporter inspects the local node on each scrape and exposes Pacemaker,
Corosync, SBD, and DRBD metrics when those components are available.

Reference
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Default runtime values:

- web.listen-address: the address on which the exporter exposes metrics.
The default is :9664.
- web.telemetry-path: the HTTP path on which metrics are exposed.
The default is /metrics.

This snap currently starts the exporter with the upstream defaults and does
not expose additional snap configuration options.

Links
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Upstream haclusterexporter repository\ https://github.com/ClusterLabs/haclusterexporter