Motivation

I want to run marathon-mesos-deimos setup (http://beingasysadmin.wordpress.com/2014/06/27/managing-docker-clusters-using-mesos-and-marathon/) on CoreOS.

I was ispired by Ebay's building from docker using hosts docker setup (http://www.ebaytechblog.com/2014/05/12/delivering-ebays-ci-solution-with-apache-mesos-part-ii/#.U85a4nV53Ua).

I want to enjoy both CoreOS and mesos resource management, in future hopefully kubernetes (https://github.com/mesosphere/kubernetes-mesos).

Prerequisites

• fleetctl
• vagrant
• virtualbox
• python
• docker-py==0.3.1
• ansible

Install

• Start CoreOS cluster
• for testing I am using vagrant - http://coreos.com/docs/running-coreos/platforms/vagrant/
• slightly customized version is in coreos-vagrant directory
• Connect to fleet from localhost - https://github.com/coreos/fleet/blob/master/Documentation/remote-access.md
• fleet is getting ssh-keys from ssh-agent so if you don't have yours there already you can add one using
• ssh-agent && vagrant ssh-config core-01 | sed -n "s/IdentityFile//gp" | xargs ssh-add
• export FLEETCTL_TUNNEL="$(vagrant ssh-config core-01 | sed -n "s/[ ]*HostName[ ]*//gp"):$(vagrant ssh-config core-01 | sed -n "s/[ ]*Port[ ]*//gp")"
• make initial changes on coreos hosts, following commnads have to be run from ansible directory
• ansible-playbook -i vagranttest coreos.yml
• submit and start following units:
• registry
• ansible-playbook -i vagranttest coreos-registry.yml
• zookeeper
• ansible-playbook -i vagranttest coreos-zookeeper.yml
• mesos-master
• ansible-playbook -i vagranttest coreos-mesos-master.yml
• mesos-slave
• ansible-playbook -i vagranttest coreos-mesos-slave.yml
• marathon
• ansible-playbook -i vagranttest coreos-marathon.yml
• Test marathon API
• curl -v -X POST -H "Content-Type: application/json" <marathon-IP>:8080/v2/apps -d@test.json
• test.json: { "id": "test", "container": {"image": "docker:///debian:jessie", "options" : []}, "cmd": "while sleep 10; do date -u +%T; done", "cpus": "0.5", "mem": "268.0", "uris": [ ], "instances": "1" }

Architecture

• Host OS
• CoreOS - https://coreos.com/
• Native Technology: - ETCD - key/value store - Fleet - cluster level systemd
  • Used for triggering cluster apps - zookeeper, mesos-master/slave, marathon - Omaha update protocol - https://github.com/coreos/go-omaha
• Mesos - Resource manager gathers resources
• Marathon - Mesos framework for running docker images
• Deimos - python Docker bindings for mesos-slave

Features

• Deploy app simply by specifying:
• image name
• cpu, ram
• No. of instances
• Fault tolerance - Environment will ensure that apps are running
• Speed
• Dev/Test
• Create stack faster on demand (Ebay has minimal stack up in 10 minutes)
• Prod
• Faster Scaling - simply run more instances of app
• Better resource utilization
• Scale apps up/down on demand
• http://blog.docker.com/2014/06/dockercon-video-cluster-management-and-containerization-at-twitter/

TODO

• Crate docker images for
• Docker Registry
• Zookeeper
• Mesos-master
• Mesos-slave
• Marathon (mesos framework)
• Run apps in HA
• Create pattern Unit files
• Idealy using some tool (ansible...)
• Set dynamic communication between services
• using etcd
• using haproxy generated from marathon (https://github.com/mesosphere/marathon)