Event driven microservices with vertx and kubernetes

BASEL BERN BRUGG DÜSSELDORF FRANKFURT A.M. FREIBURG I.BR. GENF
HAMBURG KOPENHAGEN LAUSANNE MÜNCHEN STUTTGART WIEN ZÜRICH
Event driven Microservices with
VERT.X & KubernetesAndy Moncsek
Senior Consultant
Andy.Moncsek@trivadis.com
Twitter: @AndyAHCP

Agenda
2 31.08.2016
1. Why?
2. Event driven Microservices
3. VERT.X & Hazelcast
4. Docker & Kubernetes
5. Hazelcast & Kubernetes
6. Demo
Event driven Microservices with VERT.X & Kubernetes

3 31.08.2016
Why?

Why?
 Developing one Microservice is fun
 Reduced scope
 Choose your technology/language
 Easy to deploy/test
4 31.08.2016 Event driven Microservices with VERT.X & Kubernetes

Why?
Typical microservice architecture

Why?
 Developing many Microservices can be a pain
 Complex deployment / orchestration / testing
 Service registry & lookup  latency
 DNS & Load balancer  complex

Why?
 Idea
 Avoid Service registry & lookup
 Decouple services  async + events
 Fast re-/deploy
 And more: resilient,…

8 31.08.2016
Event driven Microservices

Event driven microservice
 Asynchronously
 Any number of receivers
 Easy Load Balancing
 Pub/Sub + p2p
 No need for service discovery

Event-driven (micro-)service
 Traditional way  Message Broker
 No direct request / response
 Broker  single point of failure

Event-driven microservice
 Using an in-memory data grid
 Automatic node lookup (services)
 Failover
 Shared data  replicated in cluster
 Pub / sub
 Request / response
 NO Service discovery

12 31.08.2016
VERT.X & Hazelcast

What Vert.x is
is a tool-kit for building reactive
appications on the JVM

What Vert.x is
14 31.08.2016
scale polyglot
general purposefun

Verticles
Smallest deployable unit
Scalable
Actor-like
Access to Vertx instance
15 31.08.2016
public class Service extends AbstractVerticle {
public void start() {
this.vertx...
}
public void stop() {
}
}

Event Loop
Multi-Reactor - event loop
(N threads for N verticles on one instance)
Don’t block the Event-Loop!
Don’t call us, we call you
16 31.08.2016
server.requestHandler(request -> {
request.response().end(„Hello!");
});

Event Bus (EB)
Nervous system of Vert.x
Communicate
Distributed p2p
Pub/sub
Request-response
17 31.08.2016
EventBus eb = vertx.eventBus();
eb.send(“the.addr", “hello", ar -> {
log.info(ar.result().body());
});
eb.consumer(“the.addr", message -> {
message.reply(“don‘t know");
});

What is Hazelcast ?
is an In-Memory Data Grid
(and the default cluster provider of Vert.X)

Hazelcast
Open Source & Enterprise Edition
Features:
Distributed Caching & Compute
Clustering
Storage
Management & Security

Hazelcast Clustering
Discover Cluster Members using:
Multicast
TCP
EC2 Cloud
jclouds
20 31.08.2016
Plugins:
AWS
Azure
Kubernetes
Etcd
…

Run Vert.x inclustered mode
Vert.x default config: multicast
„java –jar service.jar –cluster“

Demo

23 31.08.2016
Demo
https://github.com/amoAHCP/kube_vertx_demo

24 31.08.2016
Docker & Kubernetes

Docker
isolation + automation + inherence + repository + versioning
25 31.08.2016
Ubuntu
image
Java
image
WildFly
image
App
image
Docker alone doesn‘t make you happy ;-)

Kubernetes
Scale
HA distributed containers
Google starts
>20billion apps/week
Gmail, Web Search, Maps…

Kubernetes
But
It is not trivial

Kubernetes
Service oriented
Services -> machines
“Let users manage
applications, not machines”

Kubernetes
Platform for hosting containers in clusteres
Docker containers across multiple hosts
Provides: monitoring, grouping, load balancing, auto-healing, scaling
Contributors: Google, Redhat, Microsoft, ...

Kubernetes – Key concepts
30 31.08.2016
1. Push Docker image to
Registry
2. Create service
3. Create Controller
4. (Scale Pods)

Kubernetes Pods
Group of containers
Same network / namespace / IP
Environmental variables
Shared volumes

Kubernetes Controller
Ensure X pods are running
Pod templates
Rolling update

Kubernetes Services
Pod discovery
IP per service
Route to pods
selected with labels
Load balancer
selector:
name: frontend
labels:
name: frontend
labels:
name: frontend
labels:
name: frontend
ports:
-port: 80
targetPort: 8181
IP: 10.3.245.51
IP: 146.148.15.33 (pub.)

Kubernetes – all together
https://github.com/brendandburns/gcp-live-k8s-
visualizer

35 31.08.2016
Hazelcast & Kubernetes

Hazelcast & Kubernetes  What we want
Case 1: Lookup all nodes (Verticles) managed by controller
 1 – N pods
 1 – X container
Case 2: Lookup all nodes in a cluster
 N services per cluster
Routing to X pods

Hazelcast & Kubernetes  What we get
>kubectl scale rc frontend --replicas=5
>kubectl scale rc read --replicas=10
>kubectl scale rc write --replicas=2

Hazelcast & Kubernetes  What we get
Easy scale- up/down of service instances
Failover provided by Kubernetes and Hazelcast
Distributed Event-Bus  each Verticle instance
Replicated shared data

Hazelcast node discovery in Kubernetes
Discover Cluster Members using:
Multicast
TCP
EC2 Cloud
jclouds
Plugins:
AWS
Azure
Kubernetes
Etcd
…

Hazelcast discovery plugin for Kubernetes
Option 1: Kubernetes REST API
Allows discovery by service name
Option 2: DNS Lookup
Enable custom cluster.xml in Vert.X  put to classpath
https://github.com/noctarius/hazelcast-kubernetes-discovery

Hazelcast node discovery in Kubernetes (2)
 Vertx-service-discovery project (similar to Hazelcast Option 1)
Option: Kubernetes REST API
Allows discovery by label OR by namespace
Enable custom cluster.xml in Vert.X  put to classpath
https://github.com/vert-x3/vertx-service-discovery

REST API<hazelcast>
<properties>

<property name="hazelcast.rest.enabled">true</property>
</properties>
…
<discovery-strategy enabled="true"
class=”….HazelcastKubernetesDiscoveryStrategy">
<properties>
<property name="service-name">frontend-verticle</property>
<property name="namespace">default</property>
</properties>
</discovery-strategy>
</hazelcast>
Missing in official Doc. !
• your Service name
• master Service!
• needs a Kubernetes
Service!
Hazelcast.xml / Cluster.xml

Vert.x / Hazelcast node discovery in Kubernetes
REST API<hazelcast>
<properties>
<property name="hazelcast.rest.enabled">true</property>
</properties>
…
<properties>
<property name="service-label-name">cluster1</property>
<property name="service-label-value">true</property>
<property name="namespace">default</property>
</properties>
</hazelcast>
Missing in official Doc. !
• Partition your cluster with
labels
• OR find all in namespace

DNS Lookup
DNS must be enabled in
Kubernetes (kube2sky)!
<hazelcast>
<properties>
<property name="hazelcast.discovery.enabled">true</property>
</properties>
…
<properties>
<property name="service-dns">cluster.local</property>
</properties>
</hazelcast>
your Service name
OR
DNS_DOMAIN name
(cluster.local  find all
containers)

45 31.08.2016
Demo
https://github.com/amoAHCP/kube_vertx_demo/tree/dns-resolving

Try this at home
Test Kubernetes in Docker
https://github.com/vyshane/kid
Many other Docker-compose based solutions available
Limitations: no public IP & access to public service
Workaround:
 kubectl get -o yaml service/myService | grep nodePort
 wget http://$(docker-machine ip):nodePort

Conclusion
Vert.x is lightweight, fast and easy to use
typical web-app, microservices, aggregator / bridge, security, integration,
stream-/event-processing
 Kubernetes :
Functional improvement over clustered infrastructure
 easy deploy, update and scale of applications

Thank you
Andy Moncsek
Senior Consultant
Andy.Moncsek@trivadis.com
Twitter: @AndyAHCP
31.08.201648 Event driven Microservices with VERT.X & Kubernetes

Event driven microservices with vertx and kubernetes

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