305 lines
8.6 KiB
Markdown
305 lines
8.6 KiB
Markdown
# Docker Swarm (mode) cluster
|
|
|
|
This section explains how to create a multi-host docker cluster with
|
|
swarm mode using [docker-machine](https://docs.docker.com/machine) and
|
|
how to deploy Træfik on it.
|
|
|
|
The cluster consists of:
|
|
|
|
- 3 servers
|
|
- 1 manager
|
|
- 2 workers
|
|
- 1 [overlay](https://docs.docker.com/engine/userguide/networking/dockernetworks/#an-overlay-network) network
|
|
(multi-host networking)
|
|
|
|
## Prerequisites
|
|
|
|
1. You will need to install [docker-machine](https://docs.docker.com/machine/)
|
|
2. You will need the latest [VirtualBox](https://www.virtualbox.org/wiki/Downloads)
|
|
|
|
## Cluster provisioning
|
|
|
|
First, let's create all the required nodes. It's a shorter version of
|
|
the [swarm tutorial](https://docs.docker.com/engine/swarm/swarm-tutorial/).
|
|
|
|
```shell
|
|
docker-machine create -d virtualbox manager
|
|
docker-machine create -d virtualbox worker1
|
|
docker-machine create -d virtualbox worker2
|
|
```
|
|
|
|
Then, let's setup the cluster, in order :
|
|
|
|
1. initialize the cluster
|
|
2. get the token for other host to join
|
|
3. on both workers, join the cluster with the token
|
|
|
|
```shell
|
|
docker-machine ssh manager "docker swarm init \
|
|
--listen-addr $(docker-machine ip manager) \
|
|
--advertise-addr $(docker-machine ip manager)"
|
|
|
|
export worker_token=$(docker-machine ssh manager "docker swarm \
|
|
join-token worker -q")
|
|
|
|
docker-machine ssh worker1 "docker swarm join \
|
|
--token=${worker_token} \
|
|
--listen-addr $(docker-machine ip worker1) \
|
|
--advertise-addr $(docker-machine ip worker1) \
|
|
$(docker-machine ip manager)"
|
|
|
|
docker-machine ssh worker2 "docker swarm join \
|
|
--token=${worker_token} \
|
|
--listen-addr $(docker-machine ip worker2) \
|
|
--advertise-addr $(docker-machine ip worker2) \
|
|
$(docker-machine ip manager)"
|
|
```
|
|
|
|
Let's validate the cluster is up and running.
|
|
|
|
```shell
|
|
docker-machine ssh manager docker node ls
|
|
ID HOSTNAME STATUS AVAILABILITY MANAGER STATUS
|
|
2a770ov9vixeadep674265u1n worker1 Ready Active
|
|
dbi3or4q8ii8elbws70g4hkdh * manager Ready Active Leader
|
|
esbhhy6vnqv90xomjaomdgy46 worker2 Ready Active
|
|
```
|
|
|
|
Finally, let's create a network for Træfik to use.
|
|
|
|
```shell
|
|
docker-machine ssh manager "docker network create --driver=overlay traefik-net"
|
|
```
|
|
|
|
## Deploy Træfik
|
|
|
|
Let's deploy Træfik as a docker service in our cluster. The only
|
|
requirement for Træfik to work with swarm mode is that it needs to run
|
|
on a manager node — we are going to use a
|
|
[constraint](https://docs.docker.com/engine/reference/commandline/service_create/#/specify-service-constraints-constraint) for
|
|
that.
|
|
|
|
```shell
|
|
docker-machine ssh manager "docker service create \
|
|
--name traefik \
|
|
--constraint=node.role==manager \
|
|
--publish 80:80 --publish 8080:8080 \
|
|
--mount type=bind,source=/var/run/docker.sock,target=/var/run/docker.sock \
|
|
--network traefik-net \
|
|
traefik \
|
|
--docker \
|
|
--docker.swarmmode \
|
|
--docker.domain=traefik \
|
|
--docker.watch \
|
|
--web"
|
|
```
|
|
|
|
Let's explain this command:
|
|
|
|
- `--publish 80:80 --publish 8080:8080`: we publish port `80` and
|
|
`8080` on the cluster.
|
|
- `--constraint=node.role==manager`: we ask docker to schedule Træfik
|
|
on a manager node.
|
|
- `--mount type=bind,source=/var/run/docker.sock,target=/var/run/docker.sock`:
|
|
we bind mount the docker socket where Træfik is scheduled to be able
|
|
to speak to the daemon.
|
|
- `--network traefik-net`: we attach the Træfik service (and thus
|
|
the underlying container) to the `traefik-net` network.
|
|
- `--docker`: enable docker backend, and `--docker.swarmmode` to
|
|
enable the swarm mode on Træfik.
|
|
- `--web`: activate the webUI on port 8080
|
|
|
|
## Deploy your apps
|
|
|
|
We can now deploy our app on the cluster,
|
|
here [whoami](https://github.com/emilevauge/whoami), a simple web
|
|
server in Go. We start 2 services, on the `traefik-net` network.
|
|
|
|
```shell
|
|
docker-machine ssh manager "docker service create \
|
|
--name whoami0 \
|
|
--label traefik.port=80 \
|
|
--network traefik-net \
|
|
emilevauge/whoami"
|
|
|
|
docker-machine ssh manager "docker service create \
|
|
--name whoami1 \
|
|
--label traefik.port=80 \
|
|
--network traefik-net \
|
|
--label traefik.backend.loadbalancer.sticky=true \
|
|
emilevauge/whoami"
|
|
```
|
|
|
|
Note that we set whoami1 to use sticky sessions (`--label traefik.backend.loadbalancer.sticky=true`). We'll demonstrate that later.
|
|
If using `docker stack deploy`, there is [a specific way that the labels must be defined in the docker-compose file](https://github.com/containous/traefik/issues/994#issuecomment-269095109).
|
|
|
|
Check that everything is scheduled and started:
|
|
|
|
```shell
|
|
docker-machine ssh manager "docker service ls"
|
|
ID NAME REPLICAS IMAGE COMMAND
|
|
ab046gpaqtln whoami0 1/1 emilevauge/whoami
|
|
cgfg5ifzrpgm whoami1 1/1 emilevauge/whoami
|
|
dtpl249tfghc traefik 1/1 traefik --docker --docker.swarmmode --docker.domain=traefik --docker.watch --web
|
|
```
|
|
|
|
## Access to your apps through Træfik
|
|
|
|
```shell
|
|
curl -H Host:whoami0.traefik http://$(docker-machine ip manager)
|
|
Hostname: 8147a7746e7a
|
|
IP: 127.0.0.1
|
|
IP: ::1
|
|
IP: 10.0.9.3
|
|
IP: fe80::42:aff:fe00:903
|
|
IP: 172.18.0.3
|
|
IP: fe80::42:acff:fe12:3
|
|
GET / HTTP/1.1
|
|
Host: 10.0.9.3:80
|
|
User-Agent: curl/7.35.0
|
|
Accept: */*
|
|
Accept-Encoding: gzip
|
|
X-Forwarded-For: 192.168.99.1
|
|
X-Forwarded-Host: 10.0.9.3:80
|
|
X-Forwarded-Proto: http
|
|
X-Forwarded-Server: 8fbc39271b4c
|
|
|
|
curl -H Host:whoami1.traefik http://$(docker-machine ip manager)
|
|
Hostname: ba2c21488299
|
|
IP: 127.0.0.1
|
|
IP: ::1
|
|
IP: 10.0.9.4
|
|
IP: fe80::42:aff:fe00:904
|
|
IP: 172.18.0.2
|
|
IP: fe80::42:acff:fe12:2
|
|
GET / HTTP/1.1
|
|
Host: 10.0.9.4:80
|
|
User-Agent: curl/7.35.0
|
|
Accept: */*
|
|
Accept-Encoding: gzip
|
|
X-Forwarded-For: 192.168.99.1
|
|
X-Forwarded-Host: 10.0.9.4:80
|
|
X-Forwarded-Proto: http
|
|
X-Forwarded-Server: 8fbc39271b4c
|
|
```
|
|
|
|
Note that as Træfik is published, you can access it from any machine
|
|
and not only the manager.
|
|
|
|
```shell
|
|
curl -H Host:whoami0.traefik http://$(docker-machine ip worker1)
|
|
Hostname: 8147a7746e7a
|
|
IP: 127.0.0.1
|
|
IP: ::1
|
|
IP: 10.0.9.3
|
|
IP: fe80::42:aff:fe00:903
|
|
IP: 172.18.0.3
|
|
IP: fe80::42:acff:fe12:3
|
|
GET / HTTP/1.1
|
|
Host: 10.0.9.3:80
|
|
User-Agent: curl/7.35.0
|
|
Accept: */*
|
|
Accept-Encoding: gzip
|
|
X-Forwarded-For: 192.168.99.1
|
|
X-Forwarded-Host: 10.0.9.3:80
|
|
X-Forwarded-Proto: http
|
|
X-Forwarded-Server: 8fbc39271b4c
|
|
|
|
curl -H Host:whoami1.traefik http://$(docker-machine ip worker2)
|
|
Hostname: ba2c21488299
|
|
IP: 127.0.0.1
|
|
IP: ::1
|
|
IP: 10.0.9.4
|
|
IP: fe80::42:aff:fe00:904
|
|
IP: 172.18.0.2
|
|
IP: fe80::42:acff:fe12:2
|
|
GET / HTTP/1.1
|
|
Host: 10.0.9.4:80
|
|
User-Agent: curl/7.35.0
|
|
Accept: */*
|
|
Accept-Encoding: gzip
|
|
X-Forwarded-For: 192.168.99.1
|
|
X-Forwarded-Host: 10.0.9.4:80
|
|
X-Forwarded-Proto: http
|
|
X-Forwarded-Server: 8fbc39271b4c
|
|
```
|
|
|
|
## Scale both services
|
|
|
|
```shell
|
|
docker-machine ssh manager "docker service scale whoami0=5"
|
|
|
|
docker-machine ssh manager "docker service scale whoami1=5"
|
|
```
|
|
|
|
|
|
Check that we now have 5 replicas of each `whoami` service:
|
|
|
|
```shell
|
|
docker-machine ssh manager "docker service ls"
|
|
ID NAME REPLICAS IMAGE COMMAND
|
|
ab046gpaqtln whoami0 5/5 emilevauge/whoami
|
|
cgfg5ifzrpgm whoami1 5/5 emilevauge/whoami
|
|
dtpl249tfghc traefik 1/1 traefik --docker --docker.swarmmode --docker.domain=traefik --docker.watch --web
|
|
```
|
|
## Access to your whoami0 through Træfik multiple times.
|
|
|
|
Repeat the following command multiple times and note that the Hostname changes each time as Traefik load balances each request against the 5 tasks.
|
|
```shell
|
|
curl -H Host:whoami0.traefik http://$(docker-machine ip manager)
|
|
Hostname: 8147a7746e7a
|
|
IP: 127.0.0.1
|
|
IP: ::1
|
|
IP: 10.0.9.3
|
|
IP: fe80::42:aff:fe00:903
|
|
IP: 172.18.0.3
|
|
IP: fe80::42:acff:fe12:3
|
|
GET / HTTP/1.1
|
|
Host: 10.0.9.3:80
|
|
User-Agent: curl/7.35.0
|
|
Accept: */*
|
|
Accept-Encoding: gzip
|
|
X-Forwarded-For: 192.168.99.1
|
|
X-Forwarded-Host: 10.0.9.3:80
|
|
X-Forwarded-Proto: http
|
|
X-Forwarded-Server: 8fbc39271b4c
|
|
```
|
|
|
|
Do the same against whoami1.
|
|
```shell
|
|
curl -H Host:whoami1.traefik http://$(docker-machine ip manager)
|
|
Hostname: ba2c21488299
|
|
IP: 127.0.0.1
|
|
IP: ::1
|
|
IP: 10.0.9.4
|
|
IP: fe80::42:aff:fe00:904
|
|
IP: 172.18.0.2
|
|
IP: fe80::42:acff:fe12:2
|
|
GET / HTTP/1.1
|
|
Host: 10.0.9.4:80
|
|
User-Agent: curl/7.35.0
|
|
Accept: */*
|
|
Accept-Encoding: gzip
|
|
X-Forwarded-For: 192.168.99.1
|
|
X-Forwarded-Host: 10.0.9.4:80
|
|
X-Forwarded-Proto: http
|
|
X-Forwarded-Server: 8fbc39271b4c
|
|
```
|
|
Wait, I thought we added the sticky flag to whoami1? Traefik relies on a cookie to maintain stickyness so you'll need to test this with a browser.
|
|
|
|
First you need to add whoami1.traefik to your hosts file:
|
|
```ssh
|
|
if [ -n "$(grep whoami1.traefik /etc/hosts)" ];
|
|
then
|
|
echo "whoami1.traefik already exists (make sure the ip is current)";
|
|
else
|
|
sudo -- sh -c -e "echo '$(docker-machine ip manager)\twhoami1.traefik'
|
|
>> /etc/hosts";
|
|
fi
|
|
```
|
|
|
|
Now open your browser and go to http://whoami1.traefik/
|
|
|
|
You will now see that stickyness is maintained.
|
|
|
|
|