Dockerhn meetup 14/11 - Toong co-working space

Docker Swarm - ready for production use.

Create Swarm with Hosted Discovery Service from Docker Hub

### Create local Virtualbox machine
$ docker-machine create --driver=virtualbox --virtualbox-memory=1024 local
### load ~local~ machine configuration into shell
$ eval "$(docker-machine env local)"
### generate a discovery token using the Docker Swarm iamge
$ docker run swarm create
..
Digest: sha256:51a30269d3f3aaa04f744280e3c118aea032f6df85b49819aee29d379ac313b5
Status: Downloaded newer image for swarm:latest
9cec215f2925252d37a485fc18a16127

Launch the Swarm Manager

create a swarm master under Virtualbox

$ docker-machine create --driver=virtualbox \
        --swarm \
        --swarm-master \
        --swarm-discovery token://9cec215f2925252d37a485fc18a16127 \
        swarm-master

Generate two Swarm nodes

$ docker-machine create --driver=virtualbox \
        --swarm \
        --swarm-discovery token://37e5adaaf34b487f8027979543f97db9 \
        swarm-agent-00
$ docker-machine create --driver=virtualbox \
        --swarm \
        --swarm-discovery token://37e5adaaf34b487f8027979543f97db9 \
        swarm-agent-01

Direct your swarm

### point Docker env to the machine running swarm master
$ eval $(docker-machine env --swarm swarm-master)
### get information on the new swarm
$ docker info
### check images currently running on your swarm
$ docker ps -a
### check swarm version
$ docker version

Create Swarm cluster with Consul service discovery (overlay network, volume demo)

Launch a Consul master

$ docker-machine create --driver=virtualbox \
        consul-master
$ docker $(docker-machine config consul-master) run -d \
        -p "8500:8500" \
        -h "consul" \
        progrium/consul -server -bootstrap

Launch a Swarm master

$ docker-machine create \
    --driver=virtualbox \
    --swarm \
    --swarm-master \
    --swarm-discovery="consul://$(docker-machine ip consul-master):8500" \
    --engine-opt="cluster-store=consul://$(docker-machine ip consul-master):8500" \
    --engine-opt="cluster-advertise=eth1:0" \
    swarm-master

Launch two Swarm nodes

$ docker-machine create \
    --driver=virtualbox \
    --swarm \
    --swarm-discovery="consul://$(docker-machine ip consul-master):8500" \
    --engine-opt="cluster-store=consul://$(docker-machine ip consul-master):8500" \
    --engine-opt="cluster-advertise=eth1:0" \
    swarm-agent-00
$ docker-machine create \
    --driver=virtualbox \
    --swarm \
    --swarm-discovery="consul://$(docker-machine ip consul-master):8500" \
    --engine-opt="cluster-store=consul://$(docker-machine ip consul-master):8500" \
    --engine-opt="cluster-advertise=eth1:0" \
    swarm-agent-01
##############################################
#### Constraint swarm node to test filter ####
##############################################
$ docker-machine create \
    --driver=virtualbox \
    --swarm \
    --swarm-discovery="consul://$(docker-machine ip consul-master):8500" \
    --engine-opt="cluster-store=consul://$(docker-machine ip consul-master):8500" \
    --engine-opt="cluster-advertise=eth1:0" \
    --engine-label="layer=web" \
    swarm-agent-02

Check info

$ eval $(docker-machine env --swarm swarm-master)
$ docker info

Multi-host networking

### Create an overlay network
$ docker network create -d overlay overlay_test
### Run couple of containers on that network
$ docker run --name=app1 -it --net=overlay_test busybox
$ docker run --name=db1 -it --net=overlay_test busybox
### remember to set eval $(docker-machine env --swarm swarm-master)

### Check info
$ cat /etc/hosts
$ ifconfig
$ ping db1
$ ping app1
$ ping app2

Demo with docker-compose

$ docker-compose --x-network-driver=overlay --x-networking up -d

Kubernetes over Swarm

$ git clone https://github.com/docker/swarm-frontends.git
$ cd kubernetes
$ docker-compose --x-networking -f k8s-swarm.yml up

Modify your .kuber/config to point to your kubernetes cluster. To do this, type docker ps and fetch the IP and port exposed from the apiserver You can then list nodes using:

$ kubectl get nodes

Scale

$ docker-compose --x-networking -f k8s-swarm.yml scale kubelet=2 proxy=2

Volume

$ docker volume create --name=data
$ docker run -it -e constraint:layer==web -v data:/data alpine /bin/sh -c "echo hello world > /data/demo"
$ docker run -it -e constraint:layer==web -v data:/data alpine cat /data/demo

Strategy

The Docker Swarm scheduler features multiple strategies for ranking nodes. The strategy you choose determines how Swarm computes ranking. When you run a new container, Swarm chooses to place it on the node with the highest computed ranking for your chosen strategy.

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

Under the spread strategy, Swarm optimizes for the node with the least number of running containers. The binpack strategy causes Swarm to optimize for the node which is most packed. The random strategy, like it sounds, chooses nodes at random regardless of their available CPU or RAM. Default strategy is spread

NOTE: demo it!

Change Strategy

$ docker-machine create \
    --driver=virtualbox \
    --swarm \
    --swarm-master \
    --swarm-discovery="consul://$(docker-machine ip consul-master):8500" \
    --engine-opt="cluster-store=consul://$(docker-machine ip consul-master):8500" \
    --engine-opt="cluster-advertise=eth1:0" \
    --engine-opt="--strategy=binpack" \
    swarm-master-01
$ eval $(docker-machine env --swarm swarm-master-01)
$ docker-compose -f swarm-strategy.yml up
$ docker-compose scale busybox=3
$ docker ps

Filter

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

### Constraint filter
$ docker run -it -e constraint:layer==web busybox

Reference

https://github.com/dave-tucker/docker-network-demos/ https://github.com/docker/community/