Obstacles when setting up Mesos/Marathon

Sebastian has already mentioned Mesos some time ago, now it’s time to have a more practical look into this framework.
We’re currently running our NWS Platform under Mesos/Marathon and are quite happy with it. Sebastians talk at last years OSDC can give you a deeper insight into our setup. We started migrating our internal coreos/etcd/fleetctl setup to Mesos with Docker and also could provide some of our customers with a new setup.
Before I will give you a short description about snares I ran into during the migration, let’s have a quick overview on how Mesos works. We will have a look at Zookeeper, Mesos, Marathon and Docker.
Zookeeper acts as centralized key-value store for the Mesos cluster and as such has to be installed on both the Mesos-Master and -Slaves
Mesos is a distributed system kernel and runs on the Mesos-Masters and Slaves. The Masters distribute jobs and workload to the slaves and therefore need to know about their available ressources, e.g. RAM and CPU
Marathon is used for orchestration of docker containers and can access on information provided by Mesos.
Docker is one way to run containerized applications and used in our setup.
As we can see, there are several programs running simultaneously which creates needs for seamless integration.
What are obstacles you might run into when setting up your own cluster?
1. Connectivity:
When you set up e.g. different VMs to run your cluster, please make sure they are connected to each other. Which might look simple, can become frustrating when the Zookeeper nodes can’t find each other due to „wrong“ etc/hosts settings, such as
127.0.1.1  localhost
This should be altered to
127.0.1.1 $hostname, e.g. mesos-slave1
2. Configuration
Whenever you make changes to your configuration, it has to be communicated through your complete cluster. Sometimes it doesn’t even a need a service restart. Sometimes you may need to reboot. In desperate times you might want to purge packages and reinstall them. In the end it will work and you will happily run into

by TRISTAR MEDIA

by TRISTAR MEDIA

Tim Albert

Senior Systems Engineer

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Tim kommt aus einem kleinen Ort zwischen Nürnberg und Ansbach, an der malerischen B14 gelegen. Er hat in Erlangen Lehramt und in Koblenz Informationsmanagement studiert. Seit Anfang 2016 ist er bei uns tätig. Zuerst im Managed Services Team, dort kümmerte Tim sich um Infrastrukturthemen und den internen Support, um dann 2019 - zusammen mit Marius - Gründungsmitglied der ITSM Abteilung zu werden. In seiner Freizeit engagiert sich Tim in der Freiwilligen Feuerwehr – als Maschinist und Atemschutzgeräteträger -, spielt im Laientheater Bauernschwänke und ist auch handwerklich ein absolutes Allroundtalent. Angefangen von Mauern hochziehen bis hin zur KNX-Verkabelung ist er jederzeit...

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