【实战】Docker Machine + Compose + Swarm
cm54
10年前
本文的案例结合了Docker的三大编排工具Docker Machine、Compose与Swarm，值得读者们参阅。
Docker现在已经推出了一些新的命令行工具，这些工具可以简单的编排（orchestration ）Docker实例、集群以及容器管理。它们是：
- Docker Machine - 让你轻松部署Docker实例到很多不同的平台。
- Docker Compose - Fig工具的替代品。
- Docker Swarm - Docker众实例的原生集群。
这三种技术中，Swarm目前不适合在生产中使用，因此在这篇文章中我不会讲关于它的太多细节。
Docker Machine
对于直接下载预编译的二进制文件来说，我决定使用 Homebrew（OS X的管理包工具）：# Make sure everything is up-to-date brew update brew doctor brew cask update brew cask doctor # install docker-machine brew cask install docker-machine
这样就安装了docker-machine。
$ docker-machine -v docker-machine version 0.1.0 $ docker-machine ls NAME ACTIVE DRIVER STATE URL SWARM $
我已经安装了 VirtualBox，并且要创建一个叫“testing”的虚拟机：
$ docker-machine create --driver virtualbox testing INFO[0000] Creating SSH key... INFO[0000] Creating VirtualBox VM... INFO[0006] Starting VirtualBox VM... INFO[0006] Waiting for VM to start... INFO[0038] "testing" has been created and is now the active machine. INFO[0038] To point your Docker client at it, run this in your shell: $(docker-machine env testing)
docker-machine使用几个命令来帮助你连接到本地安装的Docker客户端：
$ docker-machine env testing export DOCKER_TLS_VERIFY=yes export DOCKER_CERT_PATH=/Users/russ/.docker/machine/machines/testing export DOCKER_HOST=tcp://192.168.99.100:2376 $ docker-machine config testing --tls --tlscacert=/Users/russ/.docker/machine/machines/testing/ca.pem --tlscert=/Users/russ/.docker/machine/machines/testing/cert.pem --tlskey=/Users/russ/.docker/machine/machines/testing/key.pem -H="tcp://192.168.99.100:2376
我现在启用了一个虚拟机并准备使用Docker。
$ docker-machine ls NAME ACTIVE DRIVER STATE URL SWARM testing * virtualbox Running tcp://192.168.99.100:2376
和其他新安装的一样，让我们运行一个“Hello World”：
$ docker $(docker-machine config testing) run busybox echo hello world Unable to find image 'busybox:latest' locally 511136ea3c5a: Pull complete df7546f9f060: Pull complete ea13149945cb: Pull complete 4986bf8c1536: Pull complete busybox:latest: The image you are pulling has been verified. Important: image verification is a tech preview feature and should not be relied on to provide security. Status: Downloaded newer image for busybox:latest hello world
最后，你可以使用docker-machie ssh machine-name命令SSH到虚拟机：
$ docker-machine ssh testing Boot2Docker version 1.5.0, build master : a66bce5 - Tue Feb 10 23:31:27 UTC 2015 Docker version 1.5.0, build a8a31ef docker@testing:~$ uname -a Linux testing 3.18.5-tinycore64 #1 SMP Sun Feb 1 06:02:30 UTC 2015 x86_64 GNU/Linux docker@testing:~$ cat /etc/*release NAME=Boot2Docker VERSION=1.5.0 ID=boot2docker ID_LIKE=tcl VERSION_ID=1.5.0 PRETTY_NAME="Boot2Docker 1.5.0 (TCL 5.4); master : a66bce5 - Tue Feb 10 23:31:27 UTC 2015" ANSI_COLOR="1;34" HOME_URL="http://boot2docker.io" SUPPORT_URL="https://github.com/boot2docker/boot2docker" BUG_REPORT_URL="https://github.com/boot2docker/boot2docker/issues" docker@testing:$ exit $
太棒了，我现在有一个虚拟机运行在我的电脑上，接下来呢？
设计docker-machine就是和以下公有和私有的云服务提供商（以后会添加更多）一起使用的。
- Amazon EC2
- Microsoft Azure
- Digital Ocean
- Google Compute Engine
- Rackspace
- SoftLayer
- OpenStack
- VMWare vCloud Air
- VMWare vSphere
让我们使用docker-machine来启用一个Digital Ocean的实例。你需要生成一个Personal Access Token。一旦用token启用机子就会像下面所示一样：
$ docker-machine create \ → --driver digitalocean \ → --digitalocean-access-token cdb81ed0575b5a8d37cea0d06c9690daa074b1276892fc8473bdda97eb7c65ae \ → dotesting INFO[0000] Creating SSH key... INFO[0000] Creating Digital Ocean droplet... INFO[0004] Waiting for SSH... INFO[0071] Configuring Machine... INFO[0120] "dotesting" has been created and is now the active machine. INFO[0120] To point your Docker client at it, run this in your shell: $(docker-machine env dotesting)
那么发生了什么呢？docker-machine访问我的Digital Ocean账户通过API并且启用了以下配置的实例：
- OS = Ubuntu 14.04 x64
- RAM = 512MB
- HDD = 20GB SSD
- Region = NYC3
这些默认的配置可以通过提供更多的选项被修改，运行docker-machine create --help获取帮助查看所有带例子的选项。
一旦实例开启，docker-machine通过SSH连接到安装、配置以及开启的最新的Docker上。
所以，我们现在有两台Machines，一个在本地，一个在Digital Ocean上。
$ docker-machine ls NAME ACTIVE DRIVER STATE URL SWARM dotesting * digitalocean Running tcp://45.55.134.248:2376 testing virtualbox Running tcp://192.168.99.100:2376
让我们再次运行“Hello World”，但是这次使用刚才启动的那个实例：
$ docker $(docker-machine config dotesting) run busybox echo hello world Unable to find image 'busybox:latest' locally 511136ea3c5a: Pull complete df7546f9f060: Pull complete ea13149945cb: Pull complete 4986bf8c1536: Pull complete busybox:latest: The image you are pulling has been verified. Important: image verification is a tech preview feature and should not be relied on to provide security. Status: Downloaded newer image for busybox:latest hello world
并且SSH到那个机器中：
$ docker-machine ssh dotesting Welcome to Ubuntu 14.04.1 LTS (GNU/Linux 3.13.0-43-generic x86_64) Documentation: https://help.ubuntu.com/ System information as of Sat Mar 21 07:24:02 EDT 2015 System load: 0.43 Processes: 72 Usage of /: 11.4% of 19.56GB Users logged in: 0 Memory usage: 12% IP address for eth0: 45.55.134.248 Swap usage: 0% IP address for docker0: 172.17.42.1 Graph this data and manage this system at: https://landscape.canonical.com/ root@dotesting:~# docker images REPOSITORY TAG IMAGE ID CREATED VIRTUAL SIZE busybox latest 4986bf8c1536 11 weeks ago 2.433 MB root@dotesting:~# docker ps -a CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES b8a83077d858 busybox:latest "echo hello world" 4 minutes ago Exited (0) 4 minutes ago kickass_almeida root@dotesting:~# exit logout $
最终，你可以使用docker-mashie stop machine-name和docker-mashie rm machine-name来停止和移除machines。请注意当使用rm时，是不会提示你是否确定删除。
$ docker-machine ls NAME ACTIVE DRIVER STATE URL SWARM dotesting * digitalocean Running tcp://45.55.134.248:2376 testing virtualbox Running tcp://192.168.99.100:2376 $ docker-machine stop dotesting $ docker-machine ls NAME ACTIVE DRIVER STATE URL SWARM dotesting * digitalocean Stopped tcp://45.55.134.248:2376 testing virtualbox Running tcp://192.168.99.100:2376 $ docker-machine rm dotesting $ docker-machine ls NAME ACTIVE DRIVER STATE URL SWARM testing virtualbox Running tcp://192.168.99.100:2376 $
总结，以上就是docker-machie的总览。正如你看到的，它确实很方便在很多不同的供应商中来引导Docker服务实例，并且使用一个本地machine命令就可以操控他们。
Docker Compose
Docker开始充满生机是因为有了Fig， 这是我曾在以前的文章中写到过，当前版本并没有添加太多的新功能，但它开始奠定了与docker-swarm工作的基础，单击 这里查看详细日志。像docker-machine一样，我使用Homebrew公式安装docker-compose。
$ brew install docker-compose ==> Downloading https://homebrew.bintray.com/bottles/fig-1.1.0.yosemite.bottle.1.tar.gz############################################################ 100.0%
==> Pouring fig-1.1.0.yosemite.bottle.1.tar.gz ==> Caveats Bash completion has been installed to: /usr/local/etc/bash_completion.d ==> Summary /usr/local/Cellar/fig/1.1.0: 186 files, 2.2M $
然后，使用docker-machine创建一个Docker服务实例：
$ docker-machine create --driver virtualbox compose INFO[0001] Creating SSH key... INFO[0001] Creating VirtualBox VM... INFO[0007] Starting VirtualBox VM... INFO[0008] Waiting for VM to start... INFO[0041] "compose" has been created and is now the active machine. INFO[0041] To point your Docker client at it, run this in your shell: $(docker-machine env compose)
因为docker-compose不直接与docker-machine交互，我们需要告诉docker客户端那些刚刚启动的服务器实例的详细信息。
$ $(docker-machine env compose)
此命令注入所需Docker客户端的环境变量来连接到服务实例，要看到他们，你只需运行docker-machine env machine-name。
$ docker-machine env compose export DOCKER_TLS_VERIFY=yes export DOCKER_CERT_PATH=/Users/russ/.docker/machine/machines/compose export DOCKER_HOST=tcp://192.168.99.100:2376
往后它就像Fig一样，除了fig.yml文件现在应该改为docker-compose.yml，在我以前的博文里有一个fig.yml文件描述：
web: image: russmckendrick/nginx-php volumes: - ./web:/var/www/html/ ports: - 80:80 environment: PHP_POOL: mywebsite links: - db:db db: image: russmckendrick/mariadb ports: - 3306 privileged: true environment: MYSQL_ROOT_PASSWORD: wibble MYSQL_DATABASE: wibble MYSQL_USER: wibble MYSQL_PASSWORD: wibble
它启用两个容器并且把它们连接到一起，还有在Nginx容器内的/var/www/html被挂载到host的./web文件夹下。我准备运行docker-compose命令的文件夹的结构是这样的：
$ tree -a . ├── \[russ 356] docker-compose.yml └── \[russ 102] web └── \[russ 67] index.php 1 directory, 2 files
开始我要拉取需要启用的镜像，你可以忽略此部分。
$ docker-compose pull Pulling db (russmckendrick/mariadb:latest)... Pulling web (russmckendrick/nginx-php:latest)...
现在镜像已经被拉取下来，是时候开启容器了：
$ docker-compose up -d Creating example_db_1... Creating example_web_1...
我们现在有了两个正在运行的容器：
$ docker-compose ps Name Command State Ports ---------------------------------------------------------------- example_db_1 /usr/local/bin/run Up 0.0.0.0:49154->3306/tcp example_web_1 /usr/local/bin/run Up 0.0.0.0:80->80/tcp
你也可以打开浏览器：
open http://$(docker-machine ip)
在我的例子中我看到PHPinfo()页面，如下：
一旦容器开启，你可以使用docker exec来连接到容器内部：
$ docker exec -it example_web_1 bash [root@997bbe6b5c80 /]# ps aux USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND root 1 0.2 1.5 115200 15360 ? Ss 13:59 0:01 /usr/bin/python /usr/bin/supervisord -n root 16 0.0 3.2 382876 33624 ? S 13:59 0:00 php-fpm: master process (/etc/php-fpm.conf) root 17 0.0 0.2 110016 2096 ? Ss 13:59 0:00 nginx: master process nginx nginx 18 0.0 0.5 110472 5568 ? S 13:59 0:00 nginx: worker process webserv+ 19 0.0 1.5 383132 16284 ? S 13:59 0:00 php-fpm: pool mywebsite webserv+ 20 0.0 0.8 382876 8848 ? S 13:59 0:00 php-fpm: pool mywebsite webserv+ 21 0.0 0.8 382876 8848 ? S 13:59 0:00 php-fpm: pool mywebsite webserv+ 22 0.0 0.8 382876 8848 ? S 13:59 0:00 php-fpm: pool mywebsite webserv+ 23 0.0 0.8 382876 8852 ? S 13:59 0:00 php-fpm: pool mywebsite root 95 0.0 0.4 91540 4740 ? Ss 13:59 0:00 /usr/libexec/postfix/master -w postfix 97 0.0 0.6 91712 6508 ? S 13:59 0:00 qmgr -l -t unix -u postfix 200 0.0 0.6 91644 6232 ? S 14:05 0:00 pickup -l -t unix -u root 234 2.3 0.2 11748 2968 ? S 14:07 0:00 bash root 250 1.0 1.1 110012 11616 ? S 14:07 0:00 nginx root 251 0.0 0.2 19756 2212 ? R+ 14:07 0:00 ps aux [root@997bbe6b5c80 /]# exit exit $
最后你可以停止以及移除容器，当然还有Docker实例：
$ docker-compose stop && docker-compose rm --force Stopping example_web_1... Stopping example_db_1... Going to remove example_web_1, example_db_1 Removing example_db_1... Removing example_web_1... $ docker-machine rm compose $ docker-machine ls NAME ACTIVE DRIVER STATE URL SWARM $
Docker Swarm
在进一步讨论之前，先看下官方文档的警告:警告：Swarm当前是beta版本，因此后期可能会有变化。我们还不推荐在生产环境中使用。现在让我们使用Homebrew来安装docker-swarm：
$ brew install docker-swarm ==> Downloading https://homebrew.bintray.com/bottles/docker-swarm-0.1.0.yosemite.bottle.tar.gz############################################################ 100.0%
==> Pouring docker-swarm-0.1.0.yosemite.bottle.tar.gz /usr/local/Cellar/docker-swarm/0.1.0: 4 files, 8.7M
因为我们已经安装了docker-machine，我将要使用它在本地创建一个集群。首先，我们需要启动一个实例并运行swarm容器：
$ docker-machine ls NAME ACTIVE DRIVER STATE URL SWARM $ docker-machine create -d virtualbox local INFO[0001] Creating SSH key... INFO[0001] Creating VirtualBox VM... INFO[0006] Starting VirtualBox VM... INFO[0006] Waiting for VM to start... INFO[0039] "local" has been created and is now the active machine. INFO[0039] To point your Docker client at it, run this in your shell: $(docker-machine env local) $ $(docker-machine env local) $ docker run swarm create Unable to find image 'swarm:latest' locally 511136ea3c5a: Pull complete ae115241d78a: Pull complete f49087514537: Pull complete fff73787bd9f: Pull complete 97c8f6e912d7: Pull complete 33f9d1e808cf: Pull complete 62860d7acc87: Pull complete bf8b6923851d: Pull complete swarm:latest: The image you are pulling has been verified. Important: image verification is a tech preview feature and should not be relied on to provide security. Status: Downloaded newer image for swarm:latest 63e7a1adb607ce4db056a29b1f5d30cf $
正如你所见，当容器启动时，我得到了一个token：63e7a1adb607ce4db056a29b1f5d30cf，我将要用它来添加更多的节点，但是首先我们需要创建一个Swarm master：
$ docker-machine create \ → -d virtualbox \ → --swarm \ → --swarm-master \ → --swarm-discovery token://63e7a1adb607ce4db056a29b1f5d30cf \ → swarm-master INFO[0000] Creating SSH key... INFO[0000] Creating VirtualBox VM... INFO[0006] Starting VirtualBox VM... INFO[0006] Waiting for VM to start... INFO[0038] Configuring Swarm... INFO[0043] "swarm-master" has been created and is now the active machine. INFO[0043] To point your Docker client at it, run this in your shell: $(docker-machine env swarm-master)
然后，我们需要连接Docker客户端到Swarm上，这就需要将--swarm添加到$(docker-machine env machine-name)命令上：
$ $(docker-machine env --swarm swarm-master)
现在让我们添加另一个节点：
$ docker-machine create \ → -d virtualbox \ → --swarm \ → --swarm-discovery token://63e7a1adb607ce4db056a29b1f5d30cf \ → swarm-node-00 INFO[0000] Creating SSH key... INFO[0000] Creating VirtualBox VM... INFO[0006] Starting VirtualBox VM... INFO[0006] Waiting for VM to start... INFO[0039] Configuring Swarm... INFO[0048] "swarm-node-00" has been created and is now the active machine.
我们现在有了2个节点的集群 - “swarm-master”：
$ docker-machine ls NAME ACTIVE DRIVER STATE URL SWARM local virtualbox Running tcp://192.168.99.100:2376 swarm-master virtualbox Running tcp://192.168.99.101:2376 swarm-master (master) swarm-node-00 * virtualbox Running tcp://192.168.99.102:2376 swarm-master
使用docker info来获取更多有关集群的信息：
$ docker info Containers: 3 Nodes: 2 swarm-master: 192.168.99.101:2376 └ Containers: 2 └ Reserved CPUs: 0 / 4 └ Reserved Memory: 0 B / 999.9 MiB swarm-node-00: 192.168.99.102:2376 └ Containers: 1 └ Reserved CPUs: 0 / 4 └ Reserved Memory: 0 B / 999.9 MiB
太棒了，但这意味着什么？
让我们拉取一些镜像：
$ docker -H 192.168.99.101:2376 pull redis $ docker -H 192.168.99.102:2376 pull mysql
注意到我是如何在“swarm-master”上拉取redis镜像以及在swarm-node-00上拉取mysql的，现在我可以保证容器只在有镜像的那个节点上启用：
$ docker run -d --name redis1 -e affinity:image==redis redis af66148bbbc8dcd799d82448dfd133b968d34eb7066a353108bf909ea3324a58 $ docker run -d --name mysql -e affinity:image==mysql -e MYSQL_ROOT_PASSWORD=mysecretpassword -d mysql 70b2d93d6f83aa99f5ad4ebe5037e228a491a4b570609840f3f4be9780c33587 $ docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 70b2d93d6f83 mysql:latest "/entrypoint.sh mysq 3 seconds ago Up Less than a second 3306/tcp swarm-node-00/mysql af66148bbbc8 redis:latest "/entrypoint.sh redi 2 minutes ago Up 2 minutes 6379/tcp swarm-master/redis1
另一个例子是使用节点的端口，让我们在两个节点上都拉取我的nginx-php镜像：
$ docker -H 192.168.99.101:2376 pull russmckendrick/nginx-php $ docker -H 192.168.99.102:2376 pull russmckendrick/nginx-php
现在，让我们启用一个容器并绑定到80端口。
$ docker run -d -p 80:80 russmckendrick/nginx-php 2d066b2ccf28d2a1fa9edad8ac7b065266f29ecb49a8753b972780051ff83587
再有：
$ docker run -d -p 80:80 russmckendrick/nginx-php 40f5fee257bb2546a639a5dc5c2d30f8fa0ac169145e431c534f85d8db51357f
你会说这没什么特别的啊？正常来说，当试图启动第二个容器时，你会得到如下信息因为你不用将同一个端口绑定到两个容器上：
$ docker run -d -p 80:80 russmckendrick/nginx-php FATA[0000] Error response from daemon: unable to find a node with port 80 available
然而，在集群的情况下，因为Docker知道集群节点运行的是什么以及哪些端口是在使用的。Docker可以简单地通过Swarm在“swarm-node-00”上启动容器并且它知道“swarm-master”已经使用了80端口：
$ docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 40f5fee257bb russmckendrick/nginx-php:latest "/usr/local/bin/run" 4 seconds ago Up Less than a second 192.168.99.101:80->80/tcp swarm-master/elated_einstein 2d066b2ccf28 russmckendrick/nginx-php:latest "/usr/local/bin/run" 8 seconds ago Up Less than a second 192.168.99.102:80->80/tcp swarm-node-00/drunk_mestorf 70b2d93d6f83 mysql:latest "/entrypoint.sh mysq 26 minutes ago Up 26 minutes 3306/tcp swarm-node-00/mysql af66148bbbc8 redis:latest "/entrypoint.sh redi 29 minutes ago Up 29 minutes 6379/tcp swarm-master/redis1
所有这一切都没有提示或特殊的命令行，它的帮助仅仅是用它来做到这些。
正如你所看到的，docker-swarm仍然有非常大的发展潜力，但也有一些不如意的地方，如容器不能够跨节点通讯。然而，伴随着 socketplane.io（他们使用Open vSwitch开发了一个基于软件定义网络解决方案的容器）的加入，我想用不了多长时间这个问题就能得到解决。
最后，让我们删除在运行的实例：
$ docker-machine rm local swarm-master swarm-node-00
就这样吧，期待在未来的几个月这些工具的更新，我也会进一步跟进。
原文：Docker Machine, Compose & Swarm （翻译：田浩浩 校对：李颖杰）
来自：http://dockerone.com/article/275