Creating Alerts

Generating alerts directly from the dashboard (e.g., for the admin on standby who is responsible for the health of a Ceph cluster) is also possible. As mentioned earlier, most of the dashboard's monitoring functionality is based on containerized instances of Prometheus and Grafana in the background. The fact that Ceph comes with a built-in interface to provide metrics data in Prometheus format is, of course, extremely convenient. What the dashboard does not deliver so far, however, is the Prometheus component to generate and send alerts – the Alertmanager [4]. With a little manual work, you can quickly retrofit this element.

Because the Prometheus developers also offer Alertmanager as a container, this technique even works on servers that are already running the Prometheus and Grafana containers from the ceph-mgr component. Instructions are provided by the Prometheus developers online [5]. Predefined alerts for Ceph clusters can also be found online [6]. The rest then just involves putting the puzzle together: In the Alertmanager configuration, you need to add the alerting targets and store the alerts that wake up the Alertmanager in its configuration. Finally, you need to enable the ability to generate alerts through the dashboard by telling it the URL on which it can reach the Alertmanager:

ceph dashboard set-alertmanager-api-host 'http://localhost:9093'

The rest is then quite simple. The Alertmanager receives alerts from Prometheus directly from the Ceph dashboard and forwards them over the configured channels. Admittedly, such a construct has the disadvantage that it is an isolated solution because it only works for Ceph. In return, however, you get a very granular, powerful monitoring and alerting tool for Ceph.

Conclusions

The former openATTIC module has evolved into a comprehensive Ceph-monitoring environment, which the developers are continuously developing. People who deride the dashboard as nothing more than a colorful appendage are doing it an injustice: The ability to get a quick, visual overview of the cluster's status is particularly helpful in emergency situations.

By the way, the dashboard can certainly change its visual appearance depending on the product with which it is rolled out. The developers have also made sure that the Ceph dashboard can be visually adapted to a manufacturer's specifications with a theme. On SUSE, it accordingly presents itself in green (Figure 4), whereas the standard version uses the classic Ceph colors instead. Whatever the color, though, the functionality always remains the same.

Figure 4: The dashboard supports different themes. It looks a bit different on SUSE than in the original version, but the functionality remains the same.