Docker Orchestrators

Docker Orchestrators

© 2015 NetApp, Inc. All rights reserved.1

Docker Orchestrators

1) Orchestrating Containerized Applications

2) The Orchestration Ecosystem Swarm

Kubernetes

Mesos

3) Deploying an Application

4) Advanced Topics


Orchestrating Containerized Applications


Applications Are Hard

Monolithic applications

Hard to update - single massive code base

Single dimension of scalability

Waterfall development practices

Static, linear phases

Requirements

Analysis

Design

Code

Test

Deploy


Tomcat

Database

Apache

Image Service

Search Service

UI Service

WAR

Simplify the Problem

Microservices

Each component is independently developed and scaled

Everything is a platform

DevOps

Continuous Integration – Finding and fixing bugs faster

Continuous Deployment – Releasing faster


Load Balancer Tier

App Tier

Database Tier

UI Service Search Service

Image

Service

The Orchestrator Ecosystem


Multiple Swarm hosts behave like a single Docker host

Still uses Docker CLI

Uses standard Docker API

Execute containers against the cluster just like a single host

Application definitions using Compose

Not fully functional yet, network is incomplete

Docker Swarm

Image: http://www.slideshare.net/rajdeep/docker-swarm-introduction


Based on Google Borg

Abstracts applications into pods and services

Schedules containers against cluster nodes using kubelets

Kubernetes

Image: https://github.com/kubernetes/kubernetes/blob/master/docs/design/architecture.md


Mesos

Abstraction of resources: CPU, RAM, etc.

Generic execution of any task against resources

Frameworks define application types

Marathon, Chronos, Hadoop, Aurora, Jenkins, Cassandra

Marathon

Framework for scheduling applications onto Mesos providing private PaaS

Meta-framework, e.g. can start Chronos jobs

Mesos + Marathon

Image: https://mesosphere.github.io/marathon/


Important Services

Scheduling

Swarm: Spread, BinPack, random + filters

Kubernetes: FitPredicate, PriorityFunction

Marathon: Resource offers + constraints, Cluster, Group_by, Like, Unlike

Service discovery

Internal DNS which registers applications

Networking

Overlay networks: Flannel, libnetwork (SocketPlane), Weave


Deploying an Application


Our Sample Application

Multi-tier web application

Database

Web Application

Not included

Load balancer(s)

Distributed database

Horizontally scalable microservices


Use standard docker CLI

Define the application using Compose

Simple, well known syntax

Scalability of components at the command line: docker-compose scale phpmyadmin:1 db:2

Docker Swarm


Kubernetes

Pods

Group(s) of containers

Replication Controllers

Container lifecycle management

Services

Endpoint for one or more pods or replication controllers


PodReplication

Controller

App:10.0.0.1

OR

Kubernetes

Pods




Services



Application group to define multiple components

Dependency tracking

Scalability

Constraints

App components are standard Marathon definitions

Mesos + Marathon


Application Group definition

Application definition

Container definition

Mesos + Marathon





Mesos + Marathon


Advanced Topics


Persistent Storage

Swarm

volumes, volumes_from, volume_driver

Kubernetes

Persistent Volume Request mechanism

Predefined, pre-allocated units of storage

Mesos + Marathon

Persistent Volumes – Partially implemented by Mesos, not implemented by Marathon

Docker pass-through volumes


Swarm Volume Definition

Kubernetes Volume DefinitionMarathon Volume Definition

Additional Orchestrator Considerations

Authentication and authorization

Distributed configuration management

etcd, zookeeper, etc.

Secrets management

Application HA / healing

Application scaling

Logging

Monitoring


Summary


Key Takeaways

Choose the orchestrator that best fits your needs

Be conscious of complexity

Development and Operations must get along!


Other Orchestrators

Tutum

Mesosphere DCOS

Rancher

CoreOS

Nomad

OpenStack Magnum (Kubernetes/Swarm)

StackEngine

Decking


Additional Resources

Swarm

Documentation: https://docs.docker.com/swarm/

Kubernetes

Application Management Documentation - http://bit.ly/1M898gS

Mesos + Marathon

Documentation: https://mesosphere.github.io/marathon/docs/

Sample Code

https://github.com/Practical-Admin/meetup/


https://docs.docker.com/swarm/

http://bit.ly/1M898gS

https://mesosphere.github.io/marathon/docs/

https://github.com/Practical-Admin/meetup/

Thank you


Docker Orchestrators

Technology

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