Enable tracing

This guide contains the steps to enable tracing with Grafana Tempo for your MySQL Router K8s application.

To summarize:

• Deploy the Tempo charm in a COS K8s environment
• Offer interfaces for cross-model integrations
• Consume and integrate cross-model integrations
• View MySQL Router K8s traces on Grafana

Prerequisites

Enabling tracing with Tempo requires that you:

• Have deployed a Charmed MySQL K8s application
  • See How to manage MySQL K8s units
• Have deployed a Charmed MySQL Router K8s application in the same model as the Charmed MySQL application
  • See How to manage MySQL Router K8s 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 dependencies of Tempo following this tutorial. In particular, we would want to:

• Deploy the minio charm
• Deploy the s3 integrator charm
• Add a bucket in minio using a python script
• Configure s3 integrator with the minio credentials

Finally, deploy and integrate with Tempo HA in a monolithic setup.

Offer interfaces

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

To offer the Tempo integration, run

juju offer <tempo_coordinator_k8s_application_name>:tracing

Then, switch to the Charmed MySQL Router K8s model, find the offers, and integrate (relate) with them:

juju switch <k8s_controller_name>:<mysql_router_k8s_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                admin   tracing:tracing

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

juju consume k8s:admin/cos.tempo

Offer interfaces

First, deploy Grafana Agent K8s from the latest/edge channel:

juju deploy grafana-agent-k8s --channel latest/edge

Then, integrate Grafana Agent k8s with the consumed interface from the previous section:

juju integrate grafana-agent-k8s:tracing tempo:tracing

Finally, integrate Charmed MySQL Router K8s with Grafana Agent K8s:

juju integrate mysql-router-k8s:tracing grafana-agent-k8s:tracing-provider

Wait until the model settles. The following is an example of the juju status --relations on the Charmed MySQL Router K8s model:

Model     Controller  Cloud/Region        Version  SLA          Timestamp
database  k8s         microk8s/localhost  3.5.4    unsupported  18:32:28Z

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

App                Version                  Status  Scale  Charm              Channel        Rev  Address         Exposed  Message
grafana-agent-k8s  0.40.4                   active      1  grafana-agent-k8s  latest/edge     93  10.152.183.141  no       grafana-dashboards-provider: off, logging-consumer: off, send-remote-write: off
mysql-k8s          8.0.37-0ubuntu0.22.04.3  active      1  mysql-k8s          8.0/edge       201  10.152.183.58   no       
mysql-router-k8s   8.0.37-0ubuntu0.22.04.3  active      1  mysql-router-k8s                    1  10.152.183.50   no       
mysql-test-app     0.0.2                    active      1  mysql-test-app     latest/stable   51  10.152.183.162  no       

Unit                  Workload  Agent  Address       Ports  Message
grafana-agent-k8s/0*  active    idle   10.1.241.221         grafana-dashboards-provider: off, logging-consumer: off, send-remote-write: off
mysql-k8s/0*          active    idle   10.1.241.213         Primary
mysql-router-k8s/0*   active    idle   10.1.241.222         
mysql-test-app/0*     active    idle   10.1.241.218         

Integration provider                 Requirer                             Interface              Type     Message
grafana-agent-k8s:peers              grafana-agent-k8s:peers              grafana_agent_replica  peer     
grafana-agent-k8s:tracing-provider   mysql-router-k8s:tracing             tracing                regular  
mysql-k8s:database                   mysql-router-k8s:backend-database    mysql_client           regular  
mysql-k8s:database-peers             mysql-k8s:database-peers             mysql_peers            peer     
mysql-k8s:restart                    mysql-k8s:restart                    rolling_op             peer     
mysql-k8s:upgrade                    mysql-k8s:upgrade                    upgrade                peer     
mysql-router-k8s:cos                 mysql-router-k8s:cos                 cos                    peer     
mysql-router-k8s:database            mysql-test-app:database              mysql_client           regular  
mysql-router-k8s:mysql-router-peers  mysql-router-k8s:mysql-router-peers  mysql_router_peers     peer     
mysql-router-k8s:upgrade-version-a   mysql-router-k8s:upgrade-version-a   upgrade                peer     
mysql-test-app:application-peers     mysql-test-app:application-peers     application-peers      peer     
tempo:tracing                        grafana-agent-k8s: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 mysql-router-k8s as the Service Name under the Search tab to view traces belonging to Charmed MySQL Router K8s.

Below is a screenshot demonstrating a Charmed MySQL Router K8s trace:

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