Networking and Service Discovery for all containers runtimes [rkt and Docker] Ilya Dmitrichenko 

Outline • Intro to rkt • Motivation • why do I need a container network? • why to use Weave Net? • How Weave Net works • comparison to other solutions • Demo (rkt & Docker on GCE + Docker for Mac) 

I know Docker, what’s rkt? • rkt is a container runtime built by CoreOS • rkt is somewhat less opinionated then Docker • Docker uses runC, which is similar to rkt • rkt has a simpler architecture • rkt is easier to use as a building block • rkt can run Docker images 

Why do I need a container network? • you may want to use an orchestrator • some orchestrators require a network • options vary, depending on cloud provider • you need something that just works 

Why chose Weave Net? • works with any orchestrator (or without one) • provides unique IP for each container • has simple service discovery built-in • easy to setup and manage • works with all runtimes, as you will see • works the same in any cloud 

What do you mean by any orchestrator? • Kubernetes • EC2 Container Service • Docker Swarm • Apache Mesos • DC/OS 

How does Weave Net work? • lightweight micro-SDN • resilient mesh architecture • uses L2/VXLAN, supports multicast • no external config store required • all state leave on the network 

How does service discovery work? • fast in-memory DNS • simply find containers by name • no port number lookup • no port remapping • no code changes 

How does it compare? • using client-side lookup is not easy to implement and hard to debug • SRV record or directory lookup • e.g.: Consul, Zookeeper, etcd • wrapping service discovery into proxy config is not optimal and even harder to debug • e.g.: multitude of bespoke code on Github 

Step 1: Infrastructure Setup Let's say you'd like to have a cluster of 3 hosts with Docker installed • $CONTAINERS_1, $CONTAINERS_2, $CONTAINERS_3 

Step 2: Install Weave Net On all of the machines run: sudo curl --location --silent git.io/weave \ --output /usr/local/bin/weave sudo chmod +x /usr/local/bin/weave 

Step 3: Launch Weave Net On all of the machines run: weave launch \ $CONTAINERS_1 $CONTAINERS_2 $CONTAINERS_3 eval $(weave env) 

Step 3: Run your apps On each hosts run these commands on any host: docker run -d \ —-name=svc-a image docker run -d \ —-name=svc-b image docker run -d alpine ping -c3 svc-a docker run -d alpine ping -c3 scc-b 

And what about rkt? 

Live Demo! 

How can I use it with Kubernetes? 

How can I use it with Kubernetes? git.io/k8s-anywhere 

@errordeveloper