Prometheus Alertmanager on Ubuntu 24.04 LTS by cloudimg. Alertmanager is the alerting hub of the Prometheus stack: it dedupes, groups, routes, silences and inhibits alerts, then dispatches them to email, Slack, PagerDuty, OpsGenie and webhooks. The single Go binary is bound to loopback and fronted by nginx on port 80 with a per-VM HTTP Basic Auth password generated on first boot; HA clustering is disabled and silences plus the notification log live on a dedicated Azure data disk. Apache-2.0 licensed.
Prometheus Alertmanager is the open source alerting hub of the Prometheus monitoring stack. It receives alerts from Prometheus and any Alertmanager compatible client, then dedupes, groups, routes, silences and inhibits them before dispatching notifications to receivers such as email, Slack, PagerDuty, OpsGenie and generic webhooks. It ships a built-in web UI and a v2 REST API. The cloudimg image installs the pinned Alertmanager 0.33.1 single Go binary running under systemd, then locks it down for a marketplace appliance. Alertmanager is bound to loopback 127.0.0.1:9093 so its UI and API are never exposed directly, HA clustering is disabled so no gossip port is opened, and an nginx reverse proxy on port 80 adds a per-VM HTTP Basic Auth gate in front of it, with an unauthenticated /healthz endpoint for Azure Load Balancer probes. Alertmanager has no user accounts of its own, so the nginx Basic Auth credential (user admin) is the gate. A unique web UI password is generated on the first boot of every VM, and the external URL is templated from the VM public IP so UI links and silence URLs resolve correctly. A minimal valid default configuration ships so the service starts cleanly, ready for you to add your own receivers and routing tree. Silences, the notification log and peer state live on a dedicated 20 GiB Azure data disk captured into the image and re-provisioned on every VM. Backed by 24/7 cloudimg support.