介绍
Juju 是 Canonical 的服务建模和部署工具。 它支持非常广泛的云服务提供商，使您能够轻松地在任何云上部署任何您想要的服务。
此外，Juju 2.0 还支持 LXD，既适用于本地部署，也适合开发，并且可以在云实例或物理机上共同协作。此文将关注本地使用，通过一个没有任何Juju经验的LXD用户来体验。
要求
假设你已经安装了 LXD 2.0 并且配置完毕，并且是在 Ubuntu 16.04 LTS 上运行的。
步骤
设置 Juju
第一件事是在 Ubuntu 16.04 上安装 Juju 2.0。这个很简单：
stgraber@dakara:~$ sudo apt install jujuReading package lists... DoneBuilding dependency treeReading state information... DoneThe following additional packages will be installed:juju-2.0Suggested packages:juju-coreThe following NEW packages will be installed:juju juju-2.00 upgraded, 2 newly installed, 0 to remove and 0 not upgraded.Need to get 39.7 MB of archives.After this operation, 269 MB of additional disk space will be used.Do you want to continue? [Y/n]Get:1 http://us.archive.ubuntu.com/ubuntu xenial-updates/main amd64 juju-2.0 amd64 2.0~beta7-0ubuntu1.16.04.1 [39.6 MB]Get:2 http://us.archive.ubuntu.com/ubuntu xenial-updates/main amd64 juju all 2.0~beta7-0ubuntu1.16.04.1 [9,556 B]Fetched 39.7 MB in 0s (53.4 MB/s)Selecting previously unselected package juju-2.0.(Reading database ... 255132 files and directories currently installed.)Preparing to unpack .../juju-2.0_2.0~beta7-0ubuntu1.16.04.1_amd64.deb ...Unpacking juju-2.0 (2.0~beta7-0ubuntu1.16.04.1) ...Selecting previously unselected package juju.Preparing to unpack .../juju_2.0~beta7-0ubuntu1.16.04.1_all.deb ...Unpacking juju (2.0~beta7-0ubuntu1.16.04.1) ...Processing triggers for man-db (2.7.5-1) ...Setting up juju-2.0 (2.0~beta7-0ubuntu1.16.04.1) ...Setting up juju (2.0~beta7-0ubuntu1.16.04.1) ...
安装完成后，我们可以使用 LXD 启动一个新的“控制器”。这意味着 Juju 不会修改你主机上的任何东西，它会在 LXD 容器中安装它的管理服务。
现在我们创建一个“test”控制器：
stgraber@dakara:~$ juju bootstrap localhost testCreating Juju controller "local.test" on localhost/localhostBootstrapping model "admin"Starting new instance for initial controllerLaunching instance- juju-745d1be3-e93d-41a2-80d4-fbe8714230dd-machine-0Installing Juju agent on bootstrap instancePreparing for Juju GUI 2.1.2 release installationWaiting for addressAttempting to connect to 10.178.150.72:22Logging to /var/log/cloud-init-output.log on remote hostRunning apt-get updateRunning apt-get upgradeInstalling package: curlInstalling package: cpu-checkerInstalling package: bridge-utilsInstalling package: cloud-utilsInstalling package: cloud-image-utilsInstalling package: tmuxFetching tools: curl -sSfw 'tools from %{url_effective} downloaded: HTTP %{http_code}; time %{time_total}s; size %{size_download} bytes; speed %{speed_download} bytes/s ' --retry 10 -o $bin/tools.tar.gz <[https://streams.canonical.com/juju/tools/agent/2.0-beta7/juju-2.0-beta7-xenial-amd64.tgz]>Bootstrapping Juju machine agentStarting Juju machine agent (jujud-machine-0)Bootstrap agent installedWaiting for API to become available: upgrade in progress (upgrade in progress)Waiting for API to become available: upgrade in progress (upgrade in progress)Waiting for API to become available: upgrade in progress (upgrade in progress)Bootstrap complete, local.test now available.
这会花费一点时间，这时你可以看到一个正在运行的一个新的 LXD 容器：
stgraber@dakara:~$ lxc list juju-+-----------------------------------------------------+---------+----------------------+------+------------+-----------+| NAME | STATE | IPV4 | IPV6 | TYPE | SNAPSHOTS |+-----------------------------------------------------+---------+----------------------+------+------------+-----------+| juju-745d1be3-e93d-41a2-80d4-fbe8714230dd-machine-0 | RUNNING | 10.178.150.72 (eth0) | | PERSISTENT | 0 |+-----------------------------------------------------+---------+----------------------+------+------------+-----------+
在 Juju 这边，你可以确认它是有响应的，并且还没有服务运行：
stgraber@dakara:~$ juju status[Services]NAME STATUS EXPOSED CHARM[Units]ID WORKLOAD-STATUS JUJU-STATUS VERSION MACHINE PORTS PUBLIC-ADDRESS MESSAGE[Machines]ID STATE DNS INS-ID SERIES AZ
你也可以在浏览器中访问 Juju 的 GUI 界面：
stgraber@dakara:~$ juju guiOpening the Juju GUI in your browser.If it does not open, open this URL:https://10.178.150.72:17070/gui/97fa390d-96ad-44df-8b59-e15fdcfc636b/
Juju web UI
不过我更倾向使用命令行，因此我会在接下来使用。
部署一个 minecraft 服务
让我们先来一个简单的，部署在一个容器中使用一个 Juju 单元的服务。
stgraber@dakara:~$ juju deploy cs:trusty/minecraftAdded charm "cs:trusty/minecraft-3" to the model.Deploying charm "cs:trusty/minecraft-3" with the charm series "trusty".
命令返回会很快，然而这不意味着服务已经启动并运行了。你应该使用 juju status 来查看：
stgraber@dakara:~$ juju status[Services]NAME STATUS EXPOSED CHARMminecraft maintenance false cs:trusty/minecraft-3[Units]ID WORKLOAD-STATUS JUJU-STATUS VERSION MACHINE PORTS PUBLIC-ADDRESS MESSAGEminecraft/1 maintenance executing 2.0-beta7 1 10.178.150.74 (install) Installing java[Machines]ID STATE DNS INS-ID SERIES AZ1 started 10.178.150.74 juju-97fa390d-96ad-44df-8b59-e15fdcfc636b-machine-1 trusty
我们可以看到它正在忙于在刚刚创建的 LXD 容器中安装 java。
stgraber@dakara:~$ lxc list juju-+-----------------------------------------------------+---------+----------------------+------+------------+-----------+| NAME | STATE | IPV4 | IPV6 | TYPE | SNAPSHOTS |+-----------------------------------------------------+---------+----------------------+------+------------+-----------+| juju-745d1be3-e93d-41a2-80d4-fbe8714230dd-machine-0 | RUNNING | 10.178.150.72 (eth0) | | PERSISTENT | 0 |+-----------------------------------------------------+---------+----------------------+------+------------+-----------+| juju-97fa390d-96ad-44df-8b59-e15fdcfc636b-machine-1 | RUNNING | 10.178.150.74 (eth0) | | PERSISTENT | 0 |+-----------------------------------------------------+---------+----------------------+------+------------+-----------+
过一会之后，如我们所见服务就部署完毕了：
stgraber@dakara:~$ juju status[Services]NAME STATUS EXPOSED CHARMminecraft active false cs:trusty/minecraft-3[Units]ID WORKLOAD-STATUS JUJU-STATUS VERSION MACHINE PORTS PUBLIC-ADDRESS MESSAGEminecraft/1 active idle 2.0-beta7 1 25565/tcp 10.178.150.74 Ready[Machines]ID STATE DNS INS-ID SERIES AZ1 started 10.178.150.74 juju-97fa390d-96ad-44df-8b59-e15fdcfc636b-machine-1 trusty
这时你就可以启动你的 Minecraft 客户端了，将其指向 10.178.150.74，端口是 25565。现在可以在新的 minecraft 服务器上玩了!
当你不再需要它，只需运行：
stgraber@dakara:~$ juju destroy-service minecraft
只要等待几秒就好了。
部署一个更复杂的 web 应用
Juju 的主要工作是建模复杂的服务，并以可扩展的方式部署它们。
为了更好地展示，让我们部署一个 Juju “组合”。 这个组合是由网站，API，数据库，静态 Web 服务器和反向代理组成的基本 Web 服务。
所以这将扩展到 4 个互联的 LXD 容器。
stgraber@dakara:~$ juju deploy cs:~charmers/bundle/web-infrastructure-in-a-boxadded charm cs:~hp-discover/trusty/node-app-1service api deployed (charm cs:~hp-discover/trusty/node-app-1 with the series "trusty" defined by the bundle)annotations set for service apiadded charm cs:trusty/mongodb-3service mongodb deployed (charm cs:trusty/mongodb-3 with the series "trusty" defined by the bundle)annotations set for service mongodbadded charm cs:~hp-discover/trusty/nginx-4service nginx deployed (charm cs:~hp-discover/trusty/nginx-4 with the series "trusty" defined by the bundle)annotations set for service nginxadded charm cs:~hp-discover/trusty/nginx-proxy-3service nginx-proxy deployed (charm cs:~hp-discover/trusty/nginx-proxy-3 with the series "trusty" defined by the bundle)annotations set for service nginx-proxyadded charm cs:~hp-discover/trusty/website-3service website deployed (charm cs:~hp-discover/trusty/website-3 with the series "trusty" defined by the bundle)annotations set for service websiterelated mongodb:database and api:mongodbrelated website:nginx-engine and nginx:web-enginerelated api:website and nginx-proxy:websiterelated nginx-proxy:website and website:websiteadded api/0 unit to new machineadded mongodb/0 unit to new machineadded nginx/0 unit to new machineadded nginx-proxy/0 unit to new machinedeployment of bundle "cs:~charmers/bundle/web-infrastructure-in-a-box-10" completed
几秒后，你会看到 LXD 容器在运行了：
stgraber@dakara:~$ lxc list juju-+-----------------------------------------------------+---------+-----------------------+------+------------+-----------+| NAME | STATE | IPV4 | IPV6 | TYPE | SNAPSHOTS |+-----------------------------------------------------+---------+-----------------------+------+------------+-----------+| juju-745d1be3-e93d-41a2-80d4-fbe8714230dd-machine-0 | RUNNING | 10.178.150.72 (eth0) | | PERSISTENT | 0 |+-----------------------------------------------------+---------+-----------------------+------+------------+-----------+| juju-97fa390d-96ad-44df-8b59-e15fdcfc636b-machine-2 | RUNNING | 10.178.150.98 (eth0) | | PERSISTENT | 0 |+-----------------------------------------------------+---------+-----------------------+------+------------+-----------+| juju-97fa390d-96ad-44df-8b59-e15fdcfc636b-machine-3 | RUNNING | 10.178.150.29 (eth0) | | PERSISTENT | 0 |+-----------------------------------------------------+---------+-----------------------+------+------------+-----------+| juju-97fa390d-96ad-44df-8b59-e15fdcfc636b-machine-4 | RUNNING | 10.178.150.202 (eth0) | | PERSISTENT | 0 |+-----------------------------------------------------+---------+-----------------------+------+------------+-----------+| juju-97fa390d-96ad-44df-8b59-e15fdcfc636b-machine-5 | RUNNING | 10.178.150.214 (eth0) | | PERSISTENT | 0 |+-----------------------------------------------------+---------+-----------------------+------+------------+-----------+
几分钟后，所有的服务应该部署完毕并运行了：
stgraber@dakara:~$ juju status[Services]NAME STATUS EXPOSED CHARMapi unknown false cs:~hp-discover/trusty/node-app-1mongodb unknown false cs:trusty/mongodb-3nginx unknown false cs:~hp-discover/trusty/nginx-4nginx-proxy unknown false cs:~hp-discover/trusty/nginx-proxy-3website false cs:~hp-discover/trusty/website-3[Relations]SERVICE1 SERVICE2 RELATION TYPEapi mongodb database regularapi nginx-proxy website regularmongodb mongodb replica-set peernginx website nginx-engine subordinatenginx-proxy website website regular[Units]ID WORKLOAD-STATUS JUJU-STATUS VERSION MACHINE PORTS PUBLIC-ADDRESS MESSAGEapi/0 unknown idle 2.0-beta7 2 8000/tcp 10.178.150.98mongodb/0 unknown idle 2.0-beta7 3 27017/tcp,27019/tcp,27021/tcp,28017/tcp 10.178.150.29nginx-proxy/0 unknown idle 2.0-beta7 5 80/tcp 10.178.150.214nginx/0 unknown idle 2.0-beta7 4 10.178.150.202 website/0 unknown idle 2.0-beta7 10.178.150.202[Machines]ID STATE DNS INS-ID SERIES AZ2 started 10.178.150.98 juju-97fa390d-96ad-44df-8b59-e15fdcfc636b-machine-2 trusty3 started 10.178.150.29 juju-97fa390d-96ad-44df-8b59-e15fdcfc636b-machine-3 trusty4 started 10.178.150.202 juju-97fa390d-96ad-44df-8b59-e15fdcfc636b-machine-4 trusty5 started 10.178.150.214 juju-97fa390d-96ad-44df-8b59-e15fdcfc636b-machine-5 trusty
这时你就可以在 80 端口访问 http://10.178.150.214，并且会看到一个 Juju 学院页面。
Juju Academy web service
清理所有东西
如果你不需要 Juju 创建的容器并且不在乎下次需要再次启动，最简单的方法是：
stgraber@dakara:~$ juju destroy-controller test --destroy-all-modelsWARNING! This command will destroy the "local.test" controller.This includes all machines, services, data and other resources.Continue [y/N]? yDestroying controllerWaiting for hosted model resources to be reclaimedWaiting on 1 model, 4 machines, 5 servicesWaiting on 1 model, 4 machines, 5 servicesWaiting on 1 model, 4 machines, 5 servicesWaiting on 1 model, 4 machines, 5 servicesWaiting on 1 model, 4 machines, 5 servicesWaiting on 1 model, 4 machines, 5 servicesWaiting on 1 model, 4 machinesWaiting on 1 model, 4 machinesWaiting on 1 model, 4 machinesWaiting on 1 model, 4 machinesWaiting on 1 model, 4 machinesWaiting on 1 model, 4 machinesWaiting on 1 model, 2 machinesWaiting on 1 modelWaiting on 1 modelAll hosted models reclaimed, cleaning up controller machines
我们用下面的方式确认：
stgraber@dakara:~$ lxc list juju-+------+-------+------+------+------+-----------+| NAME | STATE | IPV4 | IPV6 | TYPE | SNAPSHOTS |+------+-------+------+------+------+-----------+
总结
Juju 2.0 内置的 LXD 支持使得可以用一种非常干净的方式来测试各种服务。
在 Juju charm store 中有很多预制的“组合”可以用来部署，甚至可以用多个“charm”来组合你想要的架构。
Juju 与 LXD 是一个完美的解决方案，从一个小的 Web 服务到大规模的基础设施都可以简单开发，这些都在你自己的机器上，并且不会在你的系统上造成混乱!