03-networking.sh

for i in 1 2 3; do
  docker-machine create -d virtualbox node-$i
done

eval $(docker-machine env node-1)

docker swarm init \
  --advertise-addr $(docker-machine ip node-1)

TOKEN=$(docker swarm join-token -q worker)

for i in 2 3; do
  eval $(docker-machine env node-$i)

  docker swarm join \
    --token $TOKEN \
    --advertise-addr $(docker-machine ip node-$i) \
    $(docker-machine ip node-1):2377
done

eval $(docker-machine env node-1)

docker node ls

docker service create --name go-demo-db \
  mongo:3.2.10

docker service inspect --pretty go-demo-db

docker service rm go-demo-db

docker network create --driver overlay go-demo

docker service create --name go-demo-db \
  --network go-demo \
  mongo:3.2.10

docker service inspect --pretty go-demo-db

docker service create --name util \
    --network go-demo --mode global \
    alpine sleep 1000000000

docker service ps util

ID=$(docker ps -q --filter label=com.docker.swarm.service.name=util)

docker exec -it $ID apk add --update drill

docker exec -it $ID drill go-demo-db

docker network create --driver overlay proxy

docker network ls -f "driver=overlay"

docker service create --name go-demo \
  -e DB=go-demo-db \
  --network go-demo \
  --network proxy \
  vfarcic/go-demo:1.0

docker service create --name proxy \
    -p 80:80 \
    -p 443:443 \
    -p 8080:8080 \
    --network proxy \
    -e MODE=swarm \
    vfarcic/docker-flow-proxy

docker service ps proxy

curl "$(docker-machine ip node-1):8080/v1/docker-flow-proxy/reconfigure?serviceName=go-demo&servicePath=/demo&port=8080"

curl -i "$(docker-machine ip node-1)/demo/hello"

curl -i "$(docker-machine ip node-3)/demo/hello"

NODE=$(docker service ps proxy | tail -n +2 | awk '{print $4}')

eval $(docker-machine env $NODE)

ID=$(docker ps -q \
    --filter label=com.docker.swarm.service.name=proxy)

docker exec -it \
    $ID cat /cfg/haproxy.cfg

eval $(docker-machine env node-1)

docker service scale go-demo=5

ID=$(docker ps -q --filter label=com.docker.swarm.service.name=util)

docker exec -it $ID apk add --update drill

docker exec -it $ID drill go-demo

docker-machine rm -f node-1 node-2 node-3

Are you going through this code using The DevOps 2.1 Toolkit book?

Hi Victor, yes I'm using the book. I'm in Chpt 3 Setting up a cluster

The text from the book is

All the commands from this chapter are available in the 03-networking.sh (https://gist.github.com/vfarcic/fd7d7e04e1133fc3c90084c4c1a919fe) Gist.

I strongly recommend not wasting time with Swarm. Send me an email to viktor@farcic.com and I'll send you a free copy of "The DevOps 2.3 Toolkit: Kubernetes".

Little further.

16:35 $ docker ps -a
CONTAINER ID        IMAGE                 COMMAND                  CREATED             STATUS                            PORTS               NAMES
fd247afc63a6        vfarcic/go-demo:1.0   "go-demo"                9 minutes ago       Up 6 seconds (health: starting)   8080/tcp            go-demo.1.9d434uglfzh53vmkqeqw0zlvn
e522aed5538d        vfarcic/go-demo:1.0   "go-demo"                9 minutes ago       Exited (2) 12 seconds ago                             go-demo.1.lv69xtzp42tlniuai834xn9b5
c605db4e16de        vfarcic/go-demo:1.0   "go-demo"                9 minutes ago       Exited (2) 27 seconds ago                             go-demo.1.41mc1zsqjc82d0k51idasr3dy
3c67bcccd9dd        vfarcic/go-demo:1.0   "go-demo"                9 minutes ago       Exited (2) 43 seconds ago                             go-demo.1.03i2yoirlxpyximk0k6dyninu
6eaf090b1929        vfarcic/go-demo:1.0   "go-demo"                10 minutes ago      Exited (2) 59 seconds ago                             go-demo.1.i3poq3wx4yeabg0wnytua8jxm
690c6b18a849        alpine:latest         "sleep 1000000000"       29 minutes ago      Up 20 minutes                                         util.pa11gdrab3db7tch6enx98mfn.nc1s0hd05maftw89jlu0ncmlp
091ba9e4f713        mongo:3.2.10          "/entrypoint.sh mong…"   29 minutes ago      Up 20 minutes                     27017/tcp           go-demo-db.1.s3hemcmhy9m5otm74z8yz42tg

docker logs e522aed5538d
panic: no reachable servers

goroutine 1 [running]:
panic(0x7b6480, 0xc82000b7f0)
	/usr/local/go/src/runtime/panic.go:481 +0x3e6
main.setupDb()
	/usr/src/myapp/main.go:43 +0xc5
main.main()
	/usr/src/myapp/main.go:30 +0x14
✔ ~

The gist is pulling the image from hub vfarcic/go-demo:1.0 so can't see the code in go mainline.

Current code does not have setupDb at line 43 in the main.go.

Might be good to update the gist to reflect the latest image? i.e.

docker service create --name go-demo \
   -e DB=go-demo-db \
   --network go-demo \
   --network proxy \
   vfarcic/go-demo:latest

Doing this shows the issue is with the panic when connecting to mongo, so looks like the os.Getenv("DB") is not being returned correctly or the host is not reachable or the port is not exposed.

Might be a port issue.

docker network create --attachable --driver overlay go-demo

I needed to make the network attachable to run below.

$ docker run -e DB=go-demo-db --network go-demo -it vfarcic/go-demo:latest /bin/sh
/ # env
HOSTNAME=47a4294f8e92
SHLVL=1
HOME=/root
DB=go-demo-db
TERM=xterm
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
PWD=/
/ # ping go-demo-db
PING go-demo-db (10.0.1.2): 56 data bytes
64 bytes from 10.0.1.2: seq=0 ttl=64 time=0.082 ms
64 bytes from 10.0.1.2: seq=1 ttl=64 time=0.084 ms
^C
--- go-demo-db ping statistics ---
2 packets transmitted, 2 packets received, 0% packet loss
round-trip min/avg/max = 0.082/0.083/0.084 ms
/ # telnet go-demo-db 27017

Should the create service for mongo expose the default port?

docker service create --name go-demo-db \
  --network go-demo \
  mongo:3.2.10

Not a port issue, confirmed port exposed

nmap -p 27017 go-demo-db

Starting Nmap 7.12 ( https://nmap.org ) at 2020-01-07 17:25 UTC
Nmap scan report for go-demo-db (10.0.1.2)
Host is up (-0.20s latency).
PORT      STATE    SERVICE
27017/tcp filtered mongod
MAC Address: 02:42:0A:00:01:04 (Unknown)

Nmap done: 1 IP address (1 host up) scanned in 0.46 seconds

Some progress

The problem is with the proxy network, removing this from the service create command allows the service to be created.

$ docker service create --name go-demo    -e DB=go-demo-db    --network go-demo     vfarcic/go-demo:latest
qfqpgs962otjbulsfof0wzvnt
overall progress: 1 out of 1 tasks
1/1: running   [==================================================>]
verify: Service converged