kube/monitoring/README.md

## Monitoring namespace

Prometheus is accessible at [prom.k-space.ee](https://prom.k-space.ee/)
and the corresponding AlertManager is accessible at [am.k-space.ee](https://am.k-space.ee/).
Both are [deployed by ArgoCD](https://argocd.k-space.ee/applications/monitoring)
from this Git repo directory using Prometheus operator.

Note that Prometheus and other monitoring stack components should use the
`dedicated: monitoring` Kubernetes node selector to make sure the components
get scheduled on `mon[1-3]` nodes which are hosted in a privileged VLAN where
they have access to UPS SNMP targets, Mikrotik router/switch API-s etc.

To add monitoring targets inside the Kubernetes cluster make use of
[PodMonitor](https://github.com/prometheus-operator/prometheus-operator/blob/main/Documentation/user-guides/getting-started.md#using-podmonitors) or ServiceMonitor custom
resource definitions.

For external targets (ab)use the Probe CRD as seen in `node-exporter.yaml`
or `ping-exporter.yaml`

Alerts are sent to #kube-prod Slack channel. The alerting rules are automatically
picked up by Prometheus operator via Kubernetes manifests utilizing
the operator's
[PrometheusRule](https://github.com/prometheus-operator/prometheus-operator/blob/main/Documentation/user-guides/alerting.md#deploying-prometheus-rules) custom resource definitions.

Sample queries:

* [SSD/HDD temperatures](https://prom.k-space.ee/graph?g0.expr=%7B__name__%3D~%22smartmon_(temperature_celsius%7Cairflow_temperature_cel)_raw_value%22%7D&g0.tab=0&g0.stacked=0&g0.range_input=1d)
* [HDD power on hours](https://prom.k-space.ee/graph?g0.range_input=30m&g0.expr=smartmon_power_on_hours_raw_value&g0.tab=0), 8760 hours per year
* [CPU/NB temperatures](https://prom.k-space.ee/graph?g0.range_input=1h&g0.expr=node_hwmon_temp_celsius&g0.tab=0)
* [Disk space left](https://prom.k-space.ee/graph?g0.range_input=1h&g0.expr=node_filesystem_avail_bytes&g0.tab=1)
* Minio [s3 egress](https://prom.k-space.ee/graph?g0.expr=rate(minio_s3_traffic_sent_bytes%5B3m%5D)&g0.tab=0&g0.display_mode=lines&g0.show_exemplars=0&g0.range_input=6h), [internode egress](https://prom.k-space.ee/graph?g0.expr=rate(minio_inter_node_traffic_sent_bytes%5B2m%5D)&g0.tab=0&g0.display_mode=lines&g0.show_exemplars=0&g0.range_input=6h), [storage used](https://prom.k-space.ee/graph?g0.expr=minio_node_disk_used_bytes&g0.tab=0&g0.display_mode=lines&g0.show_exemplars=0&g0.range_input=6h)

To reconfigure SNMP targets etc:

```
kubectl delete -n monitoring configmap snmp-exporter
kubectl create -n monitoring configmap snmp-exporter --from-file=snmp.yml=snmp-configs.yaml
```

To set Slack secrets:

```
 kubectl create -n monitoring secret generic slack-secrets \
    --from-literal=webhook-url=https://hooks.slack.com/services/...
```

To set Mikrotik secrets:

```
 kubectl create -n monitoring secret generic mikrotik-exporter \
  --from-literal=MIKROTIK_PASSWORD='f7W!H*Pu' \
  --from-literal=PROMETHEUS_BEARER_TOKEN=$(cat /dev/urandom | base64 | head -c 30)
```