Commit Graph

2 Commits

Author SHA1 Message Date
Stéphane Tailland 9bf9ecc358 Add Grafana's MCP server
Exposes Prometheus, Loki and Tempo as tools an LLM can call, so a question
like "what failed in the last transaction" is answered by querying rather
than by building another panel — which is where the trace dashboard kept
running out of road.

Works against OSS Grafana; the Cloud-only tools (Incidents, OnCall, Sift,
Agent Observability, Assistant) are simply absent. Verified end to end:
the MCP handshake succeeds and list_datasources returns Loki, Prometheus
and Tempo.

Authenticates with a Grafana service account token, Viewer role, created
once through /api/serviceaccounts and stored in the gitignored
k8s/secret.yaml. secret.example.yaml documents how to mint it, since
Grafana returns the value only at creation.

Two things the deployment needs that are not obvious:

  * runAsUser must be numeric. The image declares USER mcp-grafana by
    name, Kubernetes cannot resolve that to check it is not root, and
    refuses to start the container under runAsNonRoot with "image has
    non-numeric user". 1000/999 is what the image actually uses.

  * --allowed-hosts must name the Service. The server validates the Host
    header against a loopback-only default as DNS-rebinding protection, so
    the first in-cluster call returned "forbidden: host not allowed".
    Named rather than disabled with "*": the check is worth keeping.

Deliberately in-cluster only, with no OIDC and no audit trail — anything
that can reach this Service reads all the telemetry. The intended end
state is the same treatment as the five domain MCP servers, behind a Kong
gateway with openid-connect, consumer groups and http-log.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-08-27 17:21:32 +02:00
Stéphane Tailland 3937b4f366 Declarative Grafana / Prometheus / Loki / Tempo observability stack
Deploys the whole stack into the observability namespace of the local
cluster with Kustomize alone — no helm install, no dashboard created by
hand in the UI. The Makefile carries every command: deploy, dashboards,
diagnostics, PVC flush, teardown.

Dashboards are files, never UI objects. Each carries a stable uid, which
is what keeps URLs, cross-links and alerts alive across redeployments, and
references datasources by stable uid rather than by name. The dashboard
ConfigMap is generated without a name-suffix hash so applying it updates
it in place and Grafana reloads without a restart, while the provisioning
ConfigMaps keep their hash precisely so that a change there does force one.

Prometheus scrapes the kubelet /metrics/resource endpoint rather than
/metrics/cadvisor: on this cluster cadvisor exposes machine_* series only
and no container_* at all, which would leave every CPU and memory panel
empty.

Alloy ships every pod's logs to Loki through the Kubernetes API, so no
/var/log mount is needed. Tempo's metrics_generator feeds span metrics and
the service graph back into Prometheus, and the datasources are wired so a
log line's trace_id opens the matching trace.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-08-25 07:27:38 +02:00