container.training/slides/k8s/ourapponkube.md

Running our application on Kubernetes

• We can now deploy our code (as well as a redis instance)

.exercise[

• Deploy redis:

  kubectl create deployment redis --image=redis
  

• Deploy everything else:

    set -u
    for SERVICE in hasher rng webui worker; do
      kubectl create deployment $SERVICE --image=$REGISTRY/$SERVICE:$TAG
    done
  

]

---

Is this working?

• After waiting for the deployment to complete, let's look at the logs!

  (Hint: use kubectl get deploy -w to watch deployment events)

.exercise[

• Look at some logs:

  kubectl logs deploy/rng
  kubectl logs deploy/worker
  

]

--

🤔 rng is fine ... But not worker.

--

💡 Oh right! We forgot to expose.

---

Connecting containers together

• Three deployments need to be reachable by others: hasher, redis, rng

• worker doesn't need to be exposed

• webui will be dealt with later

.exercise[

• Expose each deployment, specifying the right port:

  kubectl expose deployment redis --port 6379
  kubectl expose deployment rng --port 80
  kubectl expose deployment hasher --port 80
  

]

---

Is this working yet?

• The worker has an infinite loop, that retries 10 seconds after an error

.exercise[

• Stream the worker's logs:

  kubectl logs deploy/worker --follow
  

  (Give it about 10 seconds to recover)

]

--

We should now see the worker, well, working happily.

---

Exposing services for external access

• Now we would like to access the Web UI

• We will expose it with a NodePort

  (just like we did for the registry)

.exercise[

• Create a NodePort service for the Web UI:

  kubectl expose deploy/webui --type=NodePort --port=80
  

• Check the port that was allocated:

  kubectl get svc
  

]

---

Accessing the web UI

• We can now connect to any node, on the allocated node port, to view the web UI

.exercise[

• Open the web UI in your browser (http://node-ip-address:3xxxx/)

]

--

Yes, this may take a little while to update. (Narrator: it was DNS.)

--

Alright, we're back to where we started, when we were running on a single node!