Traefik Troubleshooting Scenarios

Scenario: "San Juan": mucho Traefik

Level: Medium

Type: Fix

Access: Email

Description: There is a Traefik load balancer that must be up and running. The server and the backend services are managed by Docker Compose. Running curl -s app.sadserver | head -n1 must return the host ID of one of the backend servers, running the command again must return a new host ID. The server seems to be working some times, some others fails or just times out.

The round-robin configuration should make the webserver iterate through the back-end servers.

Test: curl -s app.sadserver | head -n1 returns something like Hostname:

The "Check My Solution" button runs the script /home/admin/agent/check.sh, which you can see and execute.

Time to Solve: 20 minutes.

Scenario: "Lyon": Migrate Ingress-NGINX to Traefik

Level: Medium

Type: Do

Access: Paid

Description: Ingress-NGINX is being retired. As the DevOps Engineer, you will replace it with Traefik on the production Kubernetes cluster in a private VPC. This scenario is a local proof-of-concept for that migration.

The current K8s cluster has a "Hello World" pod running, i.e.: curl hello.lyon.local returns "Hello world" (see note 1). You should be able to see the same content delivered via Traefik once the ingress-nginx is down.

Notes: 1: Wait at the start until k8s is fully up before doing curl, otherwise you get 503, you can check for ex with k get pod -n ingress-nginx
2: The k8s manifests are under the ~/app dir.
3: ingress-nginx was deployed with a Helm chart.
4: The Helm chart for traefik is available under /home/admin/traefik (The Traefik image is already loaded in k3s).
5: Traefik dashboard and probes/metrics port by default is :8080 but that's used by the system; use a different port or disable.
6: The domain hello.lyon.local is actually pointing to the localhost.
7: The ingress must be listening on port 80 for any IP so it can respond to localhost:80 or actually to *:80

TIP: You can use k as an alias for kubectl, and it has autocomplete enabled.

Test: When the command curl -i hello.lyon.local is executed, it returns the message Hello World, while only the traefik pod must be present (instead of ingress-nginx).

The "Check My Solution" button runs the script /home/admin/agent/check.sh, which you can see and execute.

Time to Solve: 40 minutes.