【云计算】docker三剑客如何支持分布式部署？

This blog will explain how to create multi-container application deployed on multiple hosts using Docker. This will be achieved using Docker Machine, Swarm and Compose.

Yes, all three tools together makes this blog that much more interesting!

The diagram explains the key components:

Docker Machine is used to provision multiple Docker hosts
Docker Swarm will be used to create a multi-host cluster
Each node in Docker Swarm cluster is registered/discovered using Consul
Multi-container application will be deployed using Docker Compose
WildFly and Couchbase are provisioned on different hosts
Docker multi-host networking is used for WildFly and Couchbase to communicate

In addition, Maven is used to configure Couchbase and deploy application to WildFly.

Latest instructions at Docker for Java Developers .

No story, just pure code, lets do it!

Create Discovery Service using Docker Machine

Create a Machine that will host discovery service:

docker-machine create -d=virtualbox consul-machine

Running pre-create checks...

Creating machine...

Waiting for machine to be running, this may take a few minutes...

Machine is running, waiting for SSH to be available...

Detecting operating system of created instance...

Provisioning created instance...

Copying certs to the local machine directory...

Copying certs to the remote machine...

Setting Docker configuration on the remote daemon...

To see how to connect Docker to this machine, run: docker-machine env consul-machine

Connect to this Machine:

eval $(docker-machine env consul-machine)

Run Consul service using the following Compose file:

myconsul:

  image: progrium/consul

  restart: always

  hostname: consul

  ports:

    - 8500:8500

  command: "-server -bootstrap"

This Compose file is available at https://github.com/arun-gupta/docker-images/blob/master/consul/docker-compose.yml .

docker-compose up -d

Pulling myconsul (progrium/consul:latest)...

latest: Pulling from progrium/consul

3b4d28ce80e4: Pull complete

e5ab901dcf2d: Pull complete

30ad296c0ea0: Pull complete

3dba40dec256: Pull complete

f2ef4387b95e: Pull complete

53bc8dcc4791: Pull complete

75ed0b50ba1d: Pull complete

17c3a7ed5521: Pull complete

8aca9e0ecf68: Pull complete

4d1828359d36: Pull complete

46ed7df7f742: Pull complete

b5e8ce623ef8: Pull complete

049dca6ef253: Pull complete

bdb608bc4555: Pull complete

8b3d489cfb73: Pull complete

c74500bbce24: Pull complete

9f3e605442f6: Pull complete

d9125e9e799b: Pull complete

Digest: sha256:8cc8023462905929df9a79ff67ee435a36848ce7a10f18d6d0faba9306b97274

Status: Downloaded newer image for progrium/consul:latest

Creating consul_myconsul_1

Started container can be verified as:

docker ps

CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS                                                                            NAMES

f05d8dd11e7f        progrium/consul     "/bin/start -server -"   30 seconds ago      Up 29 seconds       53/tcp, 53/udp, 8300-8302/tcp, 8400/tcp, 0.0.0.0:8500->8500/tcp, 8301-8302/udp   consul_myconsul_1

Create Docker Swarm Cluster using Docker Machine

Swarm is fully integrated with Machine, and so is the easiest way to get started.

Create a Swarm Master and point to the Consul discovery service:

docker-machine create -d virtualbox --virtualbox-disk-size "5000" --swarm --swarm-master --swarm-discovery="consul://$(docker-machine ip consul-machine):8500" --engine-opt="cluster-store=consul://$(docker-machine ip consul-machine):8500" --engine-opt="cluster-advertise=eth1:2376" swarm-master

Running pre-create checks...

Creating machine...

Waiting for machine to be running, this may take a few minutes...

Machine is running, waiting for SSH to be available...

Detecting operating system of created instance...

Provisioning created instance...

Copying certs to the local machine directory...

Copying certs to the remote machine...

Setting Docker configuration on the remote daemon...

Configuring swarm...

To see how to connect Docker to this machine, run: docker-machine env swarm-master

Few options to look here:

--swarm configures the Machine with Swarm
--swarm-master configures the created Machine to be Swarm master
--swarm-discovery defines address of the discovery service
--cluster-advertise advertise the machine on the network
--cluster-store designate a distributed k/v storage backend for the cluster
--virtualbox-disk-size sets the disk size for the created Machine to 5GB. This is required so that WildFly and Couchbase image can be downloaded on any of the nodes.

Find some information about this machine:

docker-machine inspect --format='{{json .Driver}}'  swarm-master

{"Boot2DockerImportVM":"","Boot2DockerURL":"","CPU":1,"DiskSize":5000,"HostOnlyCIDR":"192.168.99.1/24","HostOnlyNicType":"82540EM","HostOnlyPromiscMode":"deny","IPAddress":"192.168.99.102","MachineName":"swarm-master","Memory":1024,"NoShare":false,"SSHPort":51972,"SSHUser":"docker","StorePath":"/Users/arungupta/.docker/machine","SwarmDiscovery":"consul://192.168.99.100:8500","SwarmHost":"tcp://0.0.0.0:3376","SwarmMaster":true,"VBoxManager":{}}

Note that the disk size is 5GB.

Connect to the master by using the command:

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

Find some information about the cluster:

docker info

Containers: 2

Images: 1

Role: primary

Strategy: spread

Filters: health, port, dependency, affinity, constraint

Nodes: 1

 swarm-master: 192.168.99.102:2376

  └ Containers: 2

  └ Reserved CPUs: 0 / 1

  └ Reserved Memory: 0 B / 1.021 GiB

  └ Labels: executiondriver=native-0.2, kernelversion=4.1.13-boot2docker, operatingsystem=Boot2Docker 1.9.1 (TCL 6.4.1); master : cef800b - Fri Nov 20 19:33:59 UTC 2015, provider=virtualbox, storagedriver=aufs

CPUs: 1

Total Memory: 1.021 GiB

Name: d074fd97682e

Create a new Machine to join this cluster:

docker-machine create -d virtualbox --virtualbox-disk-size "5000" --swarm --swarm-discovery="consul://$(docker-machine ip consul-machine):8500" --engine-opt="cluster-store=consul://$(docker-machine ip consul-machine):8500" --engine-opt="cluster-advertise=eth1:2376" swarm-node-01

Running pre-create checks...

Creating machine...

Waiting for machine to be running, this may take a few minutes...

Machine is running, waiting for SSH to be available...

Detecting operating system of created instance...

Provisioning created instance...

Copying certs to the local machine directory...

Copying certs to the remote machine...

Setting Docker configuration on the remote daemon...

Configuring swarm...

To see how to connect Docker to this machine, run: docker-machine env swarm-node-01

Notice no --swarm-master is specified in this command. This ensure that the created Machines are worker nodes.

Create a second Swarm node to join this cluster:

docker-machine create -d virtualbox --virtualbox-disk-size "5000" --swarm --swarm-discovery="consul://$(docker-machine ip consul-machine):8500" --engine-opt="cluster-store=consul://$(docker-machine ip consul-machine):8500" --engine-opt="cluster-advertise=eth1:2376" swarm-node-02

Running pre-create checks...

Creating machine...

Waiting for machine to be running, this may take a few minutes...

Machine is running, waiting for SSH to be available...

Detecting operating system of created instance...

Provisioning created instance...

Copying certs to the local machine directory...

Copying certs to the remote machine...

Setting Docker configuration on the remote daemon...

Configuring swarm...

To see how to connect Docker to this machine, run: docker-machine env swarm-node-02

List all the created Machines:

docker-machine ls

NAME             ACTIVE   DRIVER       STATE     URL                         SWARM

consul-machine   -        virtualbox   Running   tcp://192.168.99.100:2376

swarm-master     *        virtualbox   Running   tcp://192.168.99.101:2376   swarm-master (master)

swarm-node-01    -        virtualbox   Running   tcp://192.168.99.102:2376   swarm-master

swarm-node-02    -        virtualbox   Running   tcp://192.168.99.103:2376   swarm-master

The machines that are part of the cluster have cluster’s name in the SWARM column, blank otherwise. For example, consul-machine is a standalone machine where as all other machines are part of the swarm-master cluster. The Swarm master is also identified by (master) in the SWARM column.

Connect to the Swarm cluster and find some information about it:

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

docker info

Note, --swarm is specified to connect to the Swarm cluster. Otherwise the command will connect to swarm-master Machine only.

This shows the output as:

docker info

Containers: 4

Images: 3

Role: primary

Strategy: spread

Filters: health, port, dependency, affinity, constraint

Nodes: 3

 swarm-master: 192.168.99.102:2376

  └ Containers: 2

  └ Reserved CPUs: 0 / 1

  └ Reserved Memory: 0 B / 1.021 GiB

  └ Labels: executiondriver=native-0.2, kernelversion=4.1.13-boot2docker, operatingsystem=Boot2Docker 1.9.1 (TCL 6.4.1); master : cef800b - Fri Nov 20 19:33:59 UTC 2015, provider=virtualbox, storagedriver=aufs

 swarm-node-01: 192.168.99.103:2376

  └ Containers: 1

  └ Reserved CPUs: 0 / 1

  └ Reserved Memory: 0 B / 1.021 GiB

  └ Labels: executiondriver=native-0.2, kernelversion=4.1.13-boot2docker, operatingsystem=Boot2Docker 1.9.1 (TCL 6.4.1); master : cef800b - Fri Nov 20 19:33:59 UTC 2015, provider=virtualbox, storagedriver=aufs

 swarm-node-02: 192.168.99.104:2376

  └ Containers: 1

  └ Reserved CPUs: 0 / 1

  └ Reserved Memory: 0 B / 1.021 GiB

  └ Labels: executiondriver=native-0.2, kernelversion=4.1.13-boot2docker, operatingsystem=Boot2Docker 1.9.1 (TCL 6.4.1); master : cef800b - Fri Nov 20 19:33:59 UTC 2015, provider=virtualbox, storagedriver=aufs

CPUs: 3

Total Memory: 3.064 GiB

Name: d074fd97682e

There are 3 nodes – one Swarm master and 2 Swarm worker nodes. There is a total of 4 containers running in this cluster – one Swarm agent on master and each node, and there is an additional swarm-agent-master running on the master. This can be verified by connecting to the master and listing all the containers.

List nodes in the cluster with the following command:

docker run swarm list consul://$(docker-machine ip consul-machine):8500

192.168.99.102:2376

192.168.99.103:2376

192.168.99.104:2376

Start Application Environment using Docker Compose

Make sure you are connected to the cluster by giving the command eval "$(docker-machine env --swarm swarm-master)" .

List all the networks created by Docker so far:

docker network ls

NETWORK ID          NAME                   DRIVER

33a619ddc5d2        swarm-node-02/bridge   bridge

e0b73c96ffec        swarm-node-02/none     null

b315e67f0363        swarm-node-02/host     host

879d6167be47        swarm-master/bridge    bridge

f771ddc7d957        swarm-node-01/none     null

e042754df336        swarm-node-01/host     host

d2f3b512f9dc        swarm-node-01/bridge   bridge

5b5bcf135d7b        swarm-master/none      null

fffc34eae907        swarm-master/host      host

Docker create three networks for each host automatically:

Network Name	Purpose
`bridge`	Default network that containers connect to. This is `docker0` network in all Docker installations.
`none`	Container-specific networking stack
`host`	Adds a container on hosts networking stack. Network configuration is identical to the host.

This explains a total of nine networks, three for each node, as shown in this Swarm cluster.

Use Compose file to start WildFly and Couchbase:

mycouchbase:

  container_name: "db"

  image: couchbase/server

  ports:

    - 8091:8091

    - 8092:8092

    - 8093:8093

    - 11210:11210

mywildfly:

  image: arungupta/wildfly-admin

  environment:

    - COUCHBASE_URI=db

  ports:

    - 8080:8080

    - 9990:9990

In this Compose file:

Couchbase service has a custom container name defined by container_name . This name is used when creating a new environment variable COUCHBASE_URI during WildFly startup.
arungupta/wildfly-admin image is used as it binds WildFly’s management to all network interfaces, and in addition also exposes port 9990. This enables WildFly Maven Plugin to be used to deploy the application.Source for this file is at https://github.com/arun-gupta/docker-images/blob/master/wildfly-couchbase-javaee7/docker-compose.yml .

This application environment can be started as:

docker-compose --x-networking up -d

Creating network "wildflycouchbasejavaee7" with driver "None"

Pulling mywildfly (arungupta/wildfly-admin:latest)...

swarm-node-02: Pulling arungupta/wildfly-admin:latest... : downloaded

swarm-master: Pulling arungupta/wildfly-admin:latest... : downloaded

swarm-node-01: Pulling arungupta/wildfly-admin:latest... : downloaded

Creating wildflycouchbasejavaee7_mywildfly_1

Pulling mycouchbase (couchbase/server:latest)...

swarm-node-02: Pulling couchbase/server:latest... : downloaded

swarm-master: Pulling couchbase/server:latest... : downloaded

swarm-node-01: Pulling couchbase/server:latest... : downloaded

Creating db

--x-networking creates an overlay network for the Swarm cluster. This can be verified by listing networks again:

docker network ls

NETWORK ID          NAME                            DRIVER

5e93fc34b4d9        swarm-node-01/docker_gwbridge   bridge

1c041242f51d        wildflycouchbasejavaee7         overlay

cc8697c6ce13        swarm-master/docker_gwbridge    bridge

f771ddc7d957        swarm-node-01/none              null

879d6167be47        swarm-master/bridge             bridge

5b5bcf135d7b        swarm-master/none               null

fffc34eae907        swarm-master/host               host

e042754df336        swarm-node-01/host              host

d2f3b512f9dc        swarm-node-01/bridge            bridge

33a619ddc5d2        swarm-node-02/bridge            bridge

e0b73c96ffec        swarm-node-02/none              null

b315e67f0363        swarm-node-02/host              host

Three new networks are created:

Containers connected to the multi-host network are automatically connected to the docker_gwbridge network. This network allows the containers to have external connectivity outside of their cluster, and is created on each worker node.

A new overlay network wildflycouchbasejavaee7 is created. Connect to different Swarm nodes and check that the overlay network exists on them.Lets begin with master:

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

docker network ls

NETWORK ID          NAME                      DRIVER

1c041242f51d        wildflycouchbasejavaee7   overlay

879d6167be47        bridge                    bridge

5b5bcf135d7b        none                      null

fffc34eae907        host                      host

cc8697c6ce13        docker_gwbridge           bridge

Next, with swarm-node-01 :

eval "$(docker-machine env swarm-node-01)"

docker network ls

NETWORK ID          NAME                      DRIVER

1c041242f51d        wildflycouchbasejavaee7   overlay

d2f3b512f9dc        bridge                    bridge

f771ddc7d957        none                      null

e042754df336        host                      host

5e93fc34b4d9        docker_gwbridge           bridge

Finally, with swarm-node-02 :

eval "$(docker-machine env swarm-node-02)"

docker network ls

NETWORK ID          NAME                      DRIVER

1c041242f51d        wildflycouchbasejavaee7   overlay

e0b73c96ffec        none                      null

b315e67f0363        host                      host

33a619ddc5d2        bridge                    bridge

As seen, wildflycouchbasejavaee7 overlay network exists on all Machines. This confirms that the overlay network created for Swarm cluster was added to each host in the cluster. docker_gwbridge only exists on Machines that have application containers running.

Configure Application and Database

Clone https://github.com/arun-gupta/couchbase-javaee.git . This workspace contains a simple Java EE application that is deployed on WildFly and provides a REST API over travel-sample bucket in Couchbase.

Couchbase server can be configured using REST API . The application contains a Maven profile that allows to configure Couchbase server with travel-sample bucket. This can be invoked as:

mvn install -Pcouchbase -Ddocker.host=$(docker-machine ip swarm-master)

. . .

* Server auth using Basic with user 'Administrator'

> POST /sampleBuckets/install HTTP/1.1

> Authorization: Basic QWRtaW5pc3RyYXRvcjpwYXNzd29yZA==

. . .

} [data not shown]

* upload completely sent off: 17 out of 17 bytes

< HTTP/1.1 202 Accepted

* Server Couchbase Server is not blacklisted

< Server: Couchbase Server

. . .

Deploy the application to WildFly by specifying three parameters:

Host IP address where WildFly is running
Username of a user in WildFly’s administrative realm
Password of the user specified in WildFly’s administrative realm

mvn install -Pwildfly -Dwildfly.hostname=$(docker-machine ip swarm-node-01) -Dwildfly.username=admin -Dwildfly.password=Admin#007

. . .

Nov 29, 2015 12:11:14 AM org.xnio.Xnio <clinit>

INFO: XNIO version 3.3.1.Final

Nov 29, 2015 12:11:14 AM org.xnio.nio.NioXnio <clinit>

INFO: XNIO NIO Implementation Version 3.3.1.Final

Nov 29, 2015 12:11:15 AM org.jboss.remoting3.EndpointImpl <clinit>

INFO: JBoss Remoting version 4.0.9.Final

[INFO] Authenticating against security realm: ManagementRealm

[INFO] ------------------------------------------------------------------------

[INFO] BUILD SUCCESS

[INFO] ------------------------------------------------------------------------

. . .

Access Application

Now that WildFly and Couchbase server have started, lets access the application. You need to specify IP address of the Machine where WildFly is running:

curl http://$(docker-machine ip swarm-node-01):8080/couchbase-javaee/resources/airline

[{"travel-sample":{"id":10123,"iata":"TQ","icao":"TXW","name":"Texas Wings","callsign":"TXW","type":"airline","country":"United States"}}, {"travel-sample":{"id":10642,"iata":null,"icao":"JRB","name":"Jc royal.britannica","callsign":null,"type":"airline","country":"United Kingdom"}}, {"travel-sample":{"id":112,"iata":"5W","icao":"AEU","name":"Astraeus","callsign":"FLYSTAR","type":"airline","country":"United Kingdom"}}, {"travel-sample":{"id":1355,"iata":"BA","icao":"BAW","name":"British Airways","callsign":"SPEEDBIRD","type":"airline","country":"United Kingdom"}}, {"travel-sample":{"id":10765,"iata":"K5","icao":"SQH","name":"SeaPort Airlines","callsign":"SASQUATCH","type":"airline","country":"United States"}}, {"travel-sample":{"id":13633,"iata":"WQ","icao":"PQW","name":"PanAm World Airways","callsign":null,"type":"airline","country":"United States"}}, {"travel-sample":{"id":139,"iata":"SB","icao":"ACI","name":"Air Caledonie International","callsign":"AIRCALIN","type":"airline","country":"France"}}, {"travel-sample":{"id":13391,"iata":"-+","icao":"--+","name":"U.S. Air","callsign":null,"type":"airline","country":"United States"}}, {"travel-sample":{"id":1191,"iata":"UU","icao":"REU","name":"Air Austral","callsign":"REUNION","type":"airline","country":"France"}}, {"travel-sample":{"id":1316,"iata":"FL","icao":"TRS","name":"AirTran Airways","callsign":"CITRUS","type":"airline","country":"United States"}}]

Complete set of REST API for this application is documented at github.com/arun-gupta/couchbase-javaee .

Latest instructions at Docker for Java Developers .

Enjoy!

参考资料：

Multi-host Docker Deployment with Swarm and Compose Using Weave 0.11：https://www.weave.works/multi-host-docker-deployment-with-swarm-and-compose-using-weave-0-11/

Docker Machine, Swarm and Compose for multi-container and multi-host applications with Couc...：http://www.tuicool.com/articles/u22eeee

Use Docker to Create a Multi-Container App Deployed on Multiple Hosts：https://www.voxxed.com/blog/2015/12/use-docker-to-create-a-multi-container-app-deployed-on-multiple-hosts/

Get started with multi-host networking：https://docs.docker.com/engine/userguide/networking/get-started-overlay/

Multi-Host Docker Network：https://wiredcraft.com/blog/multi-host-docker-network/