Create an application using K8S resources

Manage a conference application with K8S build blocks (PoC).

Everything starts with a Conference custom resource definition. When a new conference is created or updated/delete a shared informer push the event in a message queue where a controller deploy a dedicated K8S namespace with the application deploy.

Road to CloudConf2020? Check it out: https://cloudconf.it

Getting started

Create the cluster

kind create cluster --config kind.yaml

Start development

skaffold run

Play with conferences!

Check existing conferences

kubectl get conferences
No resources found in default namespace.

Now create a new conference

kubectl apply -f examples/cloudconf2020.yaml

Check existing conferences

kubectl get conferences
NAME            TITLE            ON DAY
cloudconf2020   CloudConf 2020   2020-03-19

Check also the dedicated namespace!

kubectl describe ns cloudconf2020
Name:         cloudconf2020
Labels:       <none>
Annotations:  <none>
Status:       Active

No resource quota.

No resource limits.

Now create a conference purchase plan

kubectl apply -f examples/cloudconf2020-plan.yaml

And get the created plan

kubectl get plan -n cloudconf2020
NAME               TITLE                     ACTIVE   PRICE
super-early-bird   Super Early Bird Ticket   true     29.9

Then create an order

kubectl apply -f examples/cloudconf2020-order-1.yaml

Then check the created order

kubectl get orders -n cloudconf2020
NAME      PLAN               COUPON   STATUS    CURRENT   DESIRED   PRICE   DATE
order-1   super-early-bird            PENDING   0         1         29.9    357d

The order is correctly created but there are not tickets because its status is "PENDING"

kubectl get tickets -n cloudconf2020
No resources found in cloudconf2020 namespace.

Tickets will be generated only where the order status is confirmed, to confirm the order you can pay for it (receiving the payment webhook), have a free plan or the Coupon value is high enough to set a free ticket (price=0)

Ticket creation

Generate a free event

cat <<EOF > meetup.yaml
apiVersion: "app.corley.it/v1"
kind: Conference
metadata:
  name: meetup
spec:
  title: "Free Meetup"
EOF
kubectl apply -f meetup.yaml

Then a free plan

cat <<EOF > plan.yaml
apiVersion: "app.corley.it/v1"
kind: Plan
metadata:
  name: free-plan
  namespace: meetup
spec:
  title: "Free Ticket"
  price: 0
  active: true
EOF
kubectl apply -f plan.yaml

Now create an order

cat <<EOF > order.yaml
apiVersion: "app.corley.it/v1"
kind: Order
metadata:
  name: order-1
  namespace: meetup
spec:
  planRef: free-plan
  price: 0
  date: "2019-01-01T08:00:00Z"
  quantity: 1
EOF
kubectl apply -f order.yaml

Becase the order price is 0 (free event in this case) the ticket generation is completely automated. Just get tickets for this order

kubectl get tickets -n meetup
NAME              ORDER     FIRSTNAME   LASTNAME
order-1-5193329   order-1

You can "scale" the order and get multiple tickets. Check this out:

kubectl scale order --replicas=6 --namespace meetup order-1

Then check your tickets

kubectl get tickets -n meetup
NAME              ORDER     FIRSTNAME   LASTNAME
order-1-2729627   order-1
order-1-3468125   order-1
order-1-3598565   order-1
order-1-5193329   order-1
order-1-9476971   order-1
order-1-9926811   order-1

Pay for a ticket

Just receive the payment event (POST call on the payment gateway)

curl -XPOST -d 'custom=order-1&payment_status=Completed&mc_gross=29.90&mc_currency=EUR' http://localhost/payment-gateway/cloudconf2020

If you check the order event list now you will see the payment confirmation event and then the tickets will be created.

Delete a conference

If you want to drop out everything about a conference, just drop the conference element

kubectl delete conference CloudConf2020

And checkout your namespaces:

NAME              STATUS        AGE
cloudconf2020     Terminating   15m
default           Active        43m
ingress-nginx     Active        32m
kconference       Active        19m
kube-node-lease   Active        43m
kube-public       Active        43m
kube-system       Active        43m

As you see the namespace is now in Terminating and soon everything will be removed!

Quota and limits for conferences

Just create a resource quota!

cat <<EOF > object-counts.yaml
apiVersion: v1
kind: ResourceQuota
metadata:
  name: conference-object-counts
  namespace: cloudconf2020
spec:
  hard:
    "count/orders.app.corley.it": "10"
    "count/tickets.app.corley.it": "10"
    "count/plans.app.corley.it": "3"
    "count/coupons.app.corley.it": "5"
EOF

Now you have limits for your conference!

kubectl apply -f object-counts.yaml

And than check your conference namespace current situation:

kubectl describe namespace cloudconf2020
Name:         cloudconf2020
Labels:       <none>
Annotations:  <none>
Status:       Active

Resource Quotas
 Name:                        conference-object-counts
 Resource                     Used  Hard
 --------                     ---   ---
 count/coupons.app.corley.it  0     5
 count/orders.app.corley.it   1     10
 count/plans.app.corley.it    1     3
 count/tickets.app.corley.it  7     10

No resource limits.

Expose nginx ingress (for KinD)

Deploy nginx ingress

kubectl apply -f https://raw.githubusercontent.com/kubernetes/ingress-nginx/master/deploy/static/mandatory.yaml
kubectl apply -f https://raw.githubusercontent.com/kubernetes/ingress-nginx/master/deploy/static/provider/baremetal/service-nodeport.yaml

Then expose the service with socat

make dev