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

Hi Victor, yes this is where it stalls.

bash -x 03-networking.sh 

...

+ docker network create --driver overlay proxy
nrxfg3ylsofyfqcrndkt52xax
+ docker network ls -f driver=overlay
NETWORK ID          NAME                DRIVER              SCOPE
ulkj0k2890ny        go-demo             overlay             swarm
m7s0kdu89tis        ingress             overlay             swarm
nrxfg3ylsofy        proxy               overlay             swarm
+ docker service create --name go-demo -e DB=go-demo-db --network go-demo --network proxy vfarcic/go-demo:1.0
3unhhv3w2x50k5otnkiw46b4h
overall progress: 0 out of 1 tasks
1/1: starting  [============================================>      ]

Can you inspect the service in a separate terminal? Something like docker service inspect go-demo --pretty. While there, output the services as well (docker service ls).

I just run the same commands and it worked fine. Do you have some kind of a firewall/VPN?

Requested outputs below.

Note, I updated the script to exit before creating the service and ran the service command manually to ensure it wasnt a timing issue.

As before I had to CTRL-C the command as it kept circling around the states.

✔ ~/projects/github.com/vfarcic/go-demo [master|✚ 1…3]
12:03 $ docker service inspect go-demo --pretty

ID:		vcqyztrqikym758h42ig3ah6b
Name:		go-demo
Service Mode:	Replicated
 Replicas:	1
Placement:
UpdateConfig:
 Parallelism:	1
 On failure:	pause
 Monitoring Period: 5s
 Max failure ratio: 0
 Update order:      stop-first
RollbackConfig:
 Parallelism:	1
 On failure:	pause
 Monitoring Period: 5s
 Max failure ratio: 0
 Rollback order:    stop-first
ContainerSpec:
 Image:		vfarcic/go-demo:1.0@sha256:a578350216c5939ee518c9f57d040cf8a54ebc5d1a85292bfdf505394b040e5b
 Env:		DB=go-demo-db
 Init:		false
Resources:
Networks: proxy go-demo
Endpoint Mode:	vip

12:03 $ docker service ls
ID                  NAME                MODE                REPLICAS            IMAGE                 PORTS
vcqyztrqikym        go-demo             replicated          0/1                 vfarcic/go-demo:1.0
dxhiwhcq7ijb        go-demo-db          replicated          1/1                 mongo:3.2.10
mxzo3gm6q4jz        util                global              3/3                 alpine:latest

Not running on a VPN, have also connected to different external networks to ensure no uplink issues.

I am running McAfee endpoint security for Mac, but the Firewall function is off.

I'll go through it tomorrow.

My Swarm skills became a bit rusty. It's been 3 years since I'm not using it. From my perspective, Swarm is dead, and that's very unfortunate. Docker (company) abandoned it and (almost) everyone switched to Kubernetes. Now I believe it is a dead technology :(

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