Enable tracing

This guide contains the steps to enable tracing with Grafana Tempo for your MySQL Router 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 MySQLRouter traces on Grafana

Prerequisites

Enabling tracing with Tempo requires that you:

• Have deployed a Charmed MySQL application
  • See How to manage MySQL units
• Have deployed a Charmed MySQL Router application in the same model as the Charmed MySQL application
  • See How to manage MySQL Router 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 MySQL Router is deployed.

To offer the Tempo integration, run

juju offer tempo-k8s:tracing

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

juju switch <machine_controller_name>:<mysql_router_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 MySQL Router with the above consumed interface:

juju integrate mysql-router:tracing tempo-k8s:tracing

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

Model     Controller  Cloud/Region         Version  SLA          Timestamp
database  lxd         localhost/localhost  3.4.3    unsupported  12:48:46Z

SAAS       Status  Store  URL
tempo-k8s  active  uk8s   admin/cos.tempo-k8s

App             Version          Status  Scale  Charm           Channel      Rev  Exposed  Message
mysql           8.0.37-0ubun...  active      1  mysql           8.0/edge     253  no       
mysql-router    8.0.37-0ubun...  active      1  mysql-router    dpe/edge     216  no       
mysql-test-app  0.0.2            active      1  mysql-test-app  latest/edge   46  no       Last written value=54713

Unit               Workload  Agent  Machine  Public address  Ports           Message
mysql-test-app/0*  active    idle   1        10.205.193.43                   Last written value=54713
  mysql-router/0*  active    idle            10.205.193.43                   
mysql/0*           active    idle   0        10.205.193.72   3306,33060/tcp  Primary

Machine  State    Address        Inst id        Base          AZ  Message
0        started  10.205.193.72  juju-7f1fdf-0  ubuntu@22.04      Running
1        started  10.205.193.43  juju-7f1fdf-1  ubuntu@22.04      Running

Integration provider                           Requirer                                       Interface                    Type         Message
mysql-router:cos                               mysql-router:cos                               cos                          peer         
mysql-router:database                          mysql-test-app:database                        mysql_client                 subordinate  
mysql-router:deprecated-shared-db-credentials  mysql-router:deprecated-shared-db-credentials  _deprecated_shared_db_peers  peer         
mysql-router:tls                               mysql-router:tls                               tls                          peer         
mysql-router:upgrade-version-a                 mysql-router:upgrade-version-a                 upgrade                      peer         
mysql-test-app:application-peers               mysql-test-app:application-peers               application-peers            peer         
mysql:database                                 mysql-router:backend-database                  mysql_client                 regular      
mysql:database-peers                           mysql:database-peers                           mysql_peers                  peer         
mysql:restart                                  mysql:restart                                  rolling_op                   peer         
mysql:upgrade                                  mysql:upgrade                                  upgrade                      peer         
tempo-k8s:tracing                              mysql-router: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 as the Service Name under the Search tab to view traces belonging to Charmed MySQL Router.

Below is a screenshot demonstrating a Charmed MySQL Router trace:

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