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jazzyray / consul-playground

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Start up the 3 vagrant managed CORE-OS instances (which have docker pre-installed)

$ vagrant up

NOTE: There is a supported CoreOS Vagrantfile here: https://github.com/coreos/coreos-vagrant/blob/master/Vagrantfile

SSH into first host and get IP address

$ vagrant ssh host-1
core@host-1 ~ $ ifconfig eth1 | grep 'inet ' | awk '{ print $2 }'
172.28.128.3

Each VM has other network adapters, but for now we’ll focus on this particular one. We can see that all 3 machines are part of the 172.28.128.0/24 network. On a production setup the different machines are probably not going to be on the same private network but we can still achieve this using virtual networks most of the time (VPC on AWS for instance).

Starting the Consul cluster

Start Consul on the three VM's in a cluster

Host-1

$(docker run --rm progrium/consul cmd:run 172.28.128.3 -d -v /mnt:/data)

Which is the same as running the following....but simpler

docker run -d -h node1 -v /mnt:/data \
-p 172.28.128.3:8300:8300 \
-p 172.28.128.3:8301:8301 \
-p 172.28.128.3:8301:8301/udp \
-p 172.28.128.3:8302:8302 \
-p 172.28.128.3:8302:8302/udp \
-p 172.28.128.3:8400:8400 \
-p 172.28.128.3:8500:8500 \
-p 172.17.42.1:53:53/udp \
progrium/consul -server -advertise 172.28.128.3 -bootstrap-expect 3

Host-2

$(docker run --rm progrium/consul cmd:run 172.28.128.4:172.28.128.3 -d -v /mnt:/data)

Which is the same as running the following.....but simpler

docker run -d -h node2 -v /mnt:/data \
-p 172.28.128.4:8300:8300 \
-p 172.28.128.4:8301:8301 \
-p 172.28.128.4:8301:8301/udp \
-p 172.28.128.4:8302:8302 \
-p 172.28.128.4:8302:8302/udp \
-p 172.28.128.4:8400:8400 \
-p 172.28.128.4:8500:8500 \
-p 172.17.42.1:53:53/udp \
progrium/consul -server -advertise 172.28.128.4 -join 172.28.128.3

Host-3

$(docker run --rm progrium/consul cmd:run 172.28.128.5:172.28.128.3 -d -v /mnt:/data)

Which is the same as running the following....but simpler

docker run -d -h node3 -v /mnt:/data \
-p 172.28.128.5:8300:8300 \
-p 172.28.128.5:8301:8301 \
-p 172.28.128.5:8301:8301/udp \
-p 172.28.128.5:8302:8302 \
-p 172.28.128.5:8302:8302/udp \
-p 172.28.128.5:8400:8400 \
-p 172.28.128.5:8500:8500 \
-p 172.17.42.1:53:53/udp \
progrium/consul -server -advertise 172.28.128.5 -join 172.28.128.3

Check that the Consul cluster is good

core@host-1 docker logs consul

Start the Registrator Docker Container

https://github.com/gliderlabs/registrator

Pull latest registrator

docker pull gliderlabs/registrator:latest

Start Registrator on Host-1

core@host-1 ~ $ export HOST_IP=$(ifconfig eth1 | grep 'inet ' | awk '{ print $2 }')
core@host-1 ~ $ docker run -d  \
                  --name=registrator \    
                   --net=host \   
                   --volume=/var/run/docker.sock:/tmp/docker.sock \
                   gliderlabs/registrator:latest \
                   consul://$HOST_IP:8500

Check that registrator is connected upto consul

$ docker logs registrator
2017/05/16 12:57:47 Starting registrator v7 ...
2017/05/16 12:57:47 Using consul adapter: consul://172.28.128.3:8500
2017/05/16 12:57:47 Connecting to backend (0/0)
2017/05/16 12:57:47 consul: current leader  172.28.128.3:8300
2017/05/16 12:57:47 Listening for Docker events ...
2017/05/16 12:57:47 Syncing services on 2 containers
2017/05/16 12:57:47 ignored: 225687414f81 no published ports
2017/05/16 12:57:47 added: 36df5ca0b79b host-1:consul:8500
2017/05/16 12:57:47 added: 36df5ca0b79b host-1:consul:8301:udp
2017/05/16 12:57:47 added: 36df5ca0b79b host-1:consul:8302:udp
2017/05/16 12:57:47 added: 36df5ca0b79b host-1:consul:53:udp
2017/05/16 12:57:47 added: 36df5ca0b79b host-1:consul:8300
2017/05/16 12:57:47 added: 36df5ca0b79b host-1:consul:8302
2017/05/16 12:57:47 added: 36df5ca0b79b host-1:consul:8400
2017/05/16 12:57:47 added: 36df5ca0b79b host-1:consul:53
2017/05/16 12:57:47 added: 36df5ca0b79b host-1:consul:8301

Start on the other two hosts.

core@host-2 ~ $ export HOST_IP=$(ifconfig eth1 | grep 'inet ' | awk '{ print $2 }')]
core@host-2 ~ $ docker run -d     --name=registrator     --net=host     --volume=/var/run/docker.sock:/tmp/docker.sock     gliderlabs/registrator:latest       consul://$HOST_IP:8500

core@host-3 ~ $ export HOST_IP=$(ifconfig eth1 | grep 'inet ' | awk '{ print $2 }')]
core@host-3 ~ $ docker run -d     --name=registrator     --net=host     --volume=/var/run/docker.sock:/tmp/docker.sock     gliderlabs/registrator:latest       consul://$HOST_IP:8500

Start CES Literal Filter Mock

https://github.com/jazzyray/cesliteralresponsefilter

Install Docker compose on the three hosts

core@host-1 ~ $ curl -L https://github.com/docker/compose/releases/download/1.13.0/docker-compose-`uname -s`-`uname -m` > ~/docker-compose
core@host-1 ~ $ sudo mkdir -p /opt/bin
core@host-1 ~ $ sudo mv ~/docker-compose /opt/bin/docker-compose
core@host-1 ~ $ sudo chown root:root /opt/bin/docker-compose
core@host-1 ~ $ sudo chmod +x /opt/bin/docker-compose
core@host-1 ~ $ whereis docker-compose
docker-compose: /opt/bin/docker-compose

GET the docker-compose.yml

core@host-1 ~ $wget https://raw.githubusercontent.com/jazzyray/cesliteralresponsefilter/master/docker-compose.yml

Upgrade Docker

update_engine_client -update

Run a simple REST service Container

docker-compose up -d

Check that registrator has registered the REST service with consul

core@host-1 ~ $ curl 172.28.128.3:8500/v1/catalog/services | jq

Response

{
 "cesliteralresponsefilter-9110": [],
 "cesliteralresponsefilter-9111": [],
 "consul": [],
 "consul-53": [
               "udp"
              ],
 "consul-8300": [],
 "consul-8301": [
                 "udp"
                ],
 "consul-8302": [
                 "udp"
                ],
 "consul-8400": [],
 "consul-8500": []
}

Get some more info from consul about the microservice

$ curl 172.28.128.3:8500/v1/catalog/service/cesliteralresponsefilter

Response

[
  {
          "Node": "host-1",
          "Address": "172.28.128.3",
          "ServiceID": "host-1:core_annotation_1:9110",
          "ServiceName": "cesliteralresponsefilter-9110",
          "ServiceTags": null,
          "ServiceAddress": "",
          "ServicePort": 9110
  },
  {
          "Node": "host-2",
          "Address": "172.28.128.4",
          "ServiceID": "host-2:core_annotation_1:9110",
          "ServiceName": "cesliteralresponsefilter-9110",
          "ServiceTags": null,
          "ServiceAddress": "",
          "ServicePort": 9110
  }
]

Use Consul DNS for the services registered in Consol (DNS loadbalancing)

Find the Docker Bridge Interface

core@host-3 ~ $ export DOCKER_BRIDGE_IP=$(ifconfig docker0 | grep 'inet' | grep -v 'inet6' | awk '{ print [ }')]

Spin up another container and ping the service using the consul service name

core@host-3 ~ $ docker run --dns $DOCKER_BRIDGE_IP --dns 8.8.8.8 --dns-search service.consul --rm --name ping_test -it busybox

The DNS response will rotate across the registered services...

Kill a docker service...and the DNS resolution will only use the live services

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