Enable tracing

This guide contains the steps to enable tracing with Grafana Tempo for your PostgreSQL application.

To summarize:

• Deploy the Tempo charm in a COS K8s environment
• Integrate it with the COS charms
• Offer interfaces for cross-model integrations
• View PostgreSQL traces on Grafana

Prerequisites

Enabling tracing with Tempo requires that you:

• Have deployed a Charmed PostgreSQL application
  • See How to scale units
• Have deployed a ‘cos-lite’ bundle from the latest/edge track in a Kubernetes environment
  • See Getting started on MicroK8s

Deploy Tempo

First, switch to the Kubernetes controller where the COS model is deployed:

juju switch <k8s_controller_name>:<cos_model_name>

Then, deploy the tempo-k8s charm:

juju deploy -n 1 tempo-k8s --channel latest/edge

Integrate with the COS charms

Integrate tempo-k8s with the COS charms as follows:

juju integrate tempo-k8s:grafana-dashboard grafana:grafana-dashboard
juju integrate tempo-k8s:grafana-source grafana:grafana-source
juju integrate tempo-k8s:ingress traefik:traefik-route
juju integrate tempo-k8s:metrics-endpoint prometheus:metrics-endpoint
juju integrate tempo-k8s:logging loki:logging

If you would like to instrument traces from the COS charms as well, create the following integrations:

juju integrate tempo-k8s:tracing alertmanager:tracing
juju integrate tempo-k8s:tracing catalogue:tracing
juju integrate tempo-k8s:tracing grafana:tracing
juju integrate tempo-k8s:tracing loki:tracing
juju integrate tempo-k8s:tracing prometheus:tracing
juju integrate tempo-k8s:tracing traefik:tracing

Offer interfaces

Next, offer interfaces for cross-model integrations from the model where Charmed PostgreSQL is deployed.

To offer the Tempo integration, run

juju offer tempo-k8s:tracing

Then, switch to the Charmed PostgreSQL model, find the offers, and integrate (relate) with them:

juju switch <machine_controller_name>:<postgresql_model_name>

juju find-offers <k8s_controller_name>:

Do not miss the “:” in the command above.

Below is a sample output where k8s is the K8s controller name and cos is the model where cos-lite and tempo-k8s are deployed:

Store  URL                            Access  Interfaces
k8s    admin/cos.tempo-k8s            admin   tracing:tracing

Next, consume this offer so that it is reachable from the current model:

juju consume k8s:admin/cos.tempo-k8s

Relate Charmed PostgreSQL with the above consumed interface:

juju integrate postgresql:tracing tempo-k8s:tracing

Wait until the model settles. The following is an example of the juju status --relations on the Charmed PostgreSQL model:

Model     Controller  Cloud/Region         Version  SLA          Timestamp
database  lxd         localhost/localhost  3.4.3    unsupported  19:32:36Z

SAAS       Status  Store  URL
tempo-k8s  active  k8s    admin/cos.tempo-k8s

App         Version  Status  Scale  Charm       Channel       Rev  Exposed  Message
postgresql  14.11    active      1  postgresql  14/candidate  422  no       

Unit           Workload  Agent  Machine  Public address  Ports     Message
postgresql/1*  active    idle   1        10.205.193.156  5432/tcp  Primary

Machine  State    Address         Inst id        Base          AZ  Message
1        started  10.205.193.156  juju-ceca46-1  ubuntu@22.04      Running

Integration provider       Requirer                   Interface         Type     Message
postgresql:database-peers  postgresql:database-peers  postgresql_peers  peer     
postgresql:restart         postgresql:restart         rolling_op        peer     
postgresql:upgrade         postgresql:upgrade         upgrade           peer     
tempo-k8s:tracing          postgresql:tracing         tracing           regular  

View traces

After this is complete, the Tempo traces will be accessible from Grafana under the Explore section with tempo-k8s as the data source. You will be able to select postgresql as the Service Name under the Search tab to view traces belonging to Charmed PostgreSQL.

Below is a screenshot demonstrating a Charmed PostgreSQL trace:

Feel free to read through the Tempo documentation at your leisure to explore its deployment and its integrations.