Mesos uses zookeeper as service discovery but sometimes your applications don't support zookeeper for service discovery, or you need to run some legacy applications that you cannot modify the source, for that I research and test different systems for service discovery in Mesos/Marathon system. I will explain the problems and advantages of the different current solutions that I tested.

1. Service discovery in
Mesos Cluster
Miguel Angel Guillen
AeriaGames GmbH

2. Who am I?
● From Elche(Spain)
● Working in Berlin
in AeriaGames
● DevOps,Sysadmin,
SRE, etc…
● Video Games

3. AERIA GAMES
Different partners and
technologies

4. Mesos
● Cluster resources
● Supports docker containers
● Is really cool
● Mesos and Beyond was before this talk!!

5. Service discovery
“Service discovery tools manage how
processes and services in a cluster can find
and talk to one another.”

6. DNS
● More basic service discovery
● But A records are really simple
● SRV records are really useful
● Few services supports SRV

7. Service Discovery tools
● Provides a service registry system
● Integrates with an API
● Provides meta-data of the service
● Use or provides a K/V store
● It provides libraries and tools

8. Service Discovery tools
● Zookeeper
K/V store
libraries
● ETCD
K/V store
libraries
REST API
● Consul
K/V store
libraries
REST API
DNS
● All can be used as K/V store for all kind of usage

9. Mesos

10. Mesos

12. Zookeeper
● Zookeeper
K/V store
libraries
● NO YET REST OR DNS!*
● Only library support**
* REST is WIP
** you can use confd for reading, but set data is still from lib or
zkshell

13. What I should do?
● There is other options
● mesos-dns
● marathon-dns
● marathon-lb
● The problem is if service discovery
pattern fits in your needs

14. Service Discovery Patterns
● Client-Side Discovery Pattern
– The client is responsible for determining the
network locations
– Load balancing is managed by the client
– Usually client supports service discovery
with a library integrated (zookeeper)

15. Service Discovery Patterns
● The Server-Side Discovery Pattern
– The client makes a request to a service via a
load balancer
– Client don’t know the service, only load
balancer
– Load Balancer use service registry via DNS
or other kind of integrations.

16. Service Discovery Antipatterns
in microservices
Server side discovery
– We add an extra hop
– Load balancer as SpoF
● Or scale with the microservice
– Adds complexity to the architecture

17. And Finally…. In Mesos

18. Layers
Marathon
Mesos
Docker RegistratorRegistrator
Mesos-dnsMesos-dns
Marathon-lbMarathon-lb
consul RegistratorRegistrator
Mesos-consul

19. Service Discovery in mesos
Registrator
– Reads the event bus of docker and adds the
service to a service registry
● Application is removed from the registry when
docker container is stopped.
– If the host crash the services are still
registered
● If the host is recovered problems can appear
– There are better solutions for using with mesos

20. Mesos-consul
mesos-consul
● “Mesos-consul automatically registers/deregisters
services run as Mesos tasks.”
● Can be deployed in mesos as task or marthon app
● Depends on consul as service registry
● Use a lot of the features of consul like tags
● Develop for mantl(CiscoCloud)

21. Service Discovery in mesos
Mesos-DNS
“Mesos-DNS enables DNS based service discovery in
Apache Mesos clusters.”
● Supports SRV records
● It has special records for marathon
– Ex: leading master: A record (leader.domain) and SRV
records (_leader._tcp.domain and _leader._udp.domain)
● Supports round robin for multiple tasks with the
same name

22. Service Discovery in mesos

23. Service discovery in
mesos/marathon
Marathon-lb
“Marathon-lb is a tool for managing HAProxy, by
consuming Marathon's app state”
● Server side service discovery
● Deployable in marathon it self
● Depends on marathon
● Is included in DCOS

24. ?

25. Vielen Dank!!