Relations
Overview
Relations provide a means to integrate applications and enable a simple communications channel. Loki Charmed Operator supports the following:
Provides
Logging
Loki Charmed Operator may receive logs from any charm that supports the loki_push_api relation interface.
For instance let’s say that we have a Promtail Charmed Operator that implements the other side (requires) of the relation.
After deploying this charm, we can relate Loki and Promtail through loki_push_api relation interface:
juju relate promtail-k8s loki-k8s
And verify the relation between both charms is created:
juju status --color --relations
Model Controller Cloud/Region Version SLA Timestamp
observability mk8s microk8s/localhost 2.9.21 unsupported 17:19:57-03:00
App Version Status Scale Charm Store Channel Rev OS Address Message
loki-k8s active 1 loki-k8s charmhub edge 11 kubernetes 10.152.183.26
promtail-k8s active 1 promtail-k8s local 0 kubernetes 10.152.183.41
Unit Workload Agent Address Ports Message
loki-k8s/0* active idle 10.1.51.38
promtail-k8s/0* active idle 10.1.51.26
Relation provider Requirer Interface Type Message
loki-k8s:logging promtail-k8s:logging loki_push_api regular
Once the relation is established, Promtail charm can start sending logs to Loki charm.
Grafana-source
Grafana aggregates logs obtained by Loki and provides a versatile dashboard to view these logs in configurable ways.
Loki relates to Grafana over the grafana_datasource interface.
For example, let’s say that we have already deployed the Grafana Charmed Operator in our observability model.
The way to relate Loki and Grafana is again very simple:
juju relate grafana-k8s loki-k8s
And verify the relation between both charms is created:
juju status --color --relations
Model Controller Cloud/Region Version SLA Timestamp
observability mk8s microk8s/localhost 2.9.21 unsupported 17:28:03-03:00
App Version Status Scale Charm Store Channel Rev OS Address Message
grafana-k8s active 1 grafana-k8s charmhub edge 14 kubernetes 10.152.183.169
loki-k8s active 1 loki-k8s charmhub edge 11 kubernetes 10.152.183.26
promtail-k8s active 1 promtail-k8s local 0 kubernetes 10.152.183.41
Unit Workload Agent Address Ports Message
grafana-k8s/0* active idle 10.1.51.35
loki-k8s/0* active idle 10.1.51.38
promtail-k8s/0* active idle 10.1.51.26
Relation provider Requirer Interface Type Message
grafana-k8s:grafana-peers grafana-k8s:grafana-peers grafana_peers peer
loki-k8s:grafana-source grafana-k8s:grafana-source grafana_datasource regular
loki-k8s:logging promtail-k8s:logging loki_push_api regular
Requires
Alertmanager receives alerts from Loki, aggregates and deduplicates them, then forwards them to specified targets.
Loki Charmed Operator relates to Alertmanager over the alertmanager_dispatch interface.
Let’s assume the we have already deployed Alertmanager Charmed Operator in our obsevability model, and relate it with Loki:
juju relate alertmanager-k8s loki-k8s
We can check the relation is established:
juju status --color --relations
Model Controller Cloud/Region Version SLA Timestamp
observability mk8s microk8s/localhost 2.9.21 unsupported 17:34:39-03:00
App Version Status Scale Charm Store Channel Rev OS Address Message
alertmanager-k8s active 1 alertmanager-k8s charmhub edge 7 kubernetes 10.152.183.136
grafana-k8s active 1 grafana-k8s charmhub edge 14 kubernetes 10.152.183.169
loki-k8s active 1 loki-k8s charmhub edge 11 kubernetes 10.152.183.26
promtail-k8s active 1 promtail-k8s local 0 kubernetes 10.152.183.41
Unit Workload Agent Address Ports Message
alertmanager-k8s/0* active idle 10.1.51.29
grafana-k8s/0* active idle 10.1.51.35
loki-k8s/0* active idle 10.1.51.38
promtail-k8s/0* active idle 10.1.51.26
Relation provider Requirer Interface Type Message
alertmanager-k8s:alerting loki-k8s:alertmanager alertmanager_dispatch regular
alertmanager-k8s:replicas alertmanager-k8s:replicas alertmanager_replica peer
grafana-k8s:grafana-peers grafana-k8s:grafana-peers grafana_peers peer
loki-k8s:grafana-source grafana-k8s:grafana-source grafana_datasource regular
loki-k8s:logging promtail-k8s:logging loki_push_api regular