Exporting Metrics
By design, Linkerd only keeps metrics data for a short, fixed window of time (currently, 6 hours). This means that if Linkerd’s metrics data is valuable to you, you will probably want to export it into a full-fledged metrics store.
Internally, Linkerd stores its metrics in a Prometheus instance that runs as part of the Viz extension. The following tutorial requires the viz extension to be installed with prometheus enabled. There are several basic approaches to exporting metrics data from Linkerd:
- Federating data to your own Prometheus cluster
- Using a Prometheus integration
- Extracting data via Prometheus’s APIs
- Gather data from the proxies directly
Using the Prometheus federation API
If you are using Prometheus as your own metrics store, we recommend taking advantage of Prometheus’s federation API, which is designed exactly for the use case of copying data from one Prometheus to another.
Simply add the following item to your scrape_configs
in your Prometheus config file (replace {{.Namespace}}
with the namespace where the Linkerd Viz extension is running):
- job_name: 'linkerd'
kubernetes_sd_configs:
- role: pod
namespaces:
names: ['{{.Namespace}}']
relabel_configs:
- source_labels:
- __meta_kubernetes_pod_container_name
action: keep
regex: ^prometheus$
honor_labels: true
metrics_path: '/federate'
params:
'match[]':
- '{job="linkerd-proxy"}'
- '{job="linkerd-controller"}'
Alternatively, if you prefer to use Prometheus’ ServiceMonitors to configure your Prometheus, you can use this ServiceMonitor YAML (replace {{.Namespace}}
with the namespace where Linkerd Viz extension is running):
apiVersion: monitoring.coreos.com/v1
kind: ServiceMonitor
metadata:
labels:
k8s-app: linkerd-prometheus
release: monitoring
name: linkerd-federate
namespace: {{.Namespace}}
spec:
endpoints:
- interval: 30s
scrapeTimeout: 30s
params:
match[]:
- '{job="linkerd-proxy"}'
- '{job="linkerd-controller"}'
path: /federate
port: admin-http
honorLabels: true
relabelings:
- action: keep
regex: '^prometheus$'
sourceLabels:
- '__meta_kubernetes_pod_container_name'
jobLabel: app
namespaceSelector:
matchNames:
- {{.Namespace}}
selector:
matchLabels:
component: prometheus
That’s it! Your Prometheus cluster is now configured to federate Linkerd’s metrics from Linkerd’s internal Prometheus instance.
Once the metrics are in your Prometheus, Linkerd’s proxy metrics will have the label job="linkerd-proxy"
and Linkerd’s control plane metrics will have the label job="linkerd-controller"
. For more information on specific metric and label definitions, have a look at Proxy Metrics.
For more information on Prometheus’ /federate
endpoint, have a look at the Prometheus federation docs.
Using a Prometheus integration
If you are not using Prometheus as your own long-term data store, you may be able to leverage one of Prometheus’s many integrations to automatically extract data from Linkerd’s Prometheus instance into the data store of your choice. Please refer to the Prometheus documentation for details.
Extracting data via Prometheus’s APIs
If neither Prometheus federation nor Prometheus integrations are options for you, it is possible to call Prometheus’s APIs to extract data from Linkerd.
For example, you can call the federation API directly via a command like:
curl -G \
--data-urlencode 'match[]={job="linkerd-proxy"}' \
--data-urlencode 'match[]={job="linkerd-controller"}' \
http://prometheus.linkerd-viz.svc.cluster.local:9090/federate
Note
If your data store is outside the Kubernetes cluster, it is likely that you’ll want to set up ingress at a domain name of your choice with authentication.
Similar to the /federate
API, Prometheus provides a JSON query API to retrieve all metrics:
curl http://prometheus.linkerd-viz.svc.cluster.local:9090/api/v1/query?query=request_total
Gathering data from the Linkerd proxies directly
Finally, if you want to avoid Linkerd’s Prometheus entirely, you can query the Linkerd proxies directly on their /metrics
endpoint.
For example, to view /metrics
from a single Linkerd proxy, running in the linkerd
namespace:
kubectl -n linkerd port-forward \
$(kubectl -n linkerd get pods \
-l linkerd.io/control-plane-ns=linkerd \
-o jsonpath='{.items[0].metadata.name}') \
4191:4191
and then:
curl localhost:4191/metrics
Alternatively, linkerd diagnostics proxy-metrics
can be used to retrieve proxy metrics for a given workload.