[tutorial] build your first application on coreos

【 Editor's words 】 The author uses his own Mac Take notebook as an example , Introduced how to in CoreOS Installation on WordPress application , There is not much theoretical explanation , All are practical tutorials , I want to know quickly CoreOS Of the students reading .

I'm sure you've heard of CoreOS, But have you actually deployed an application on it ？ Many people may not have deployed . stay CoreOS Building an application on is very difficult and frustrating （ translator's note ：frustrating, Used this word , It seems really difficult ）. Because the documents are scattered , And you have to learn all the relevant skills before you start , Include etcd、systemd、Docker. If you are lazy like me , Just want to try CoreOS Instead of making a mountain out of a molehill , Then let me help you . Next we will be in CoreOS Create a simple WordPress Application and MySQL database .

If you're using Mac, You can control by installing command line tools CoreOS

fleetctl  and  etcdctl  Is the original control CoreOS colony Tools for , The installation steps are as follows ：

1. brew install go etcdctl  git clone https://github.com/coreos/fleet.git
2. $ cd fleet
3. $ ./build
4. $ mv bin/fleetctl /usr/local/bin/

Install a local CoreOS colony , And run

Vagrant It's very simple .

1. $ git clone https://github.com/CenturyLinkLabs/coreos-vagrant  $ cd coreos-vagrant/cluster
2. $ vagrant up --provision

Now there is one on your notebook by the smallest 3 individual CoreOS System composition colony . It's very simple , Now let's use fleetctl Let's check .

1. $ fleetctl list-machines MACHINE IP METADATA
2. 09fd0a88...10.0.2.15-
3. 77763947...10.0.2.15-
4. f31c383c...10.0.2.15-

fantastic , Run up .

Use fleet stay CoreOS colony Deployment application

Now you have a CoreOS colony 了 . Next fleetctl Commands can make you CoreOS Deploy applications on cluster nodes , But use fleet Write service file . Of course , You don't need to write it yourself . You can use simple YAML Format to generate Services （service） file .

$ sudo gem install bundler fig2coreos
$ cat fig.yml

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1. web:
2. image: ctlc/wordpress
3. ports:
4. - 80:80
5. environment:
6. DB_USER: root
7. DB_PASSWORD: qa1N76pWAri9
8. links:
9. - db
10. db:
11. image: ctlc/mysql
12. ports:
13. - 3306:3306
14. environment:
15. MYSQL_DATABASE: wordpress
16. MYSQL_ROOT_PASSWORD: qa1N76pWAri9

-

1. $ fig2coreos myapp fig.yml coreos-files
2. $ cd coreos-files
3. $ ls
4. db-discovery.1.service
5. db.1.service
6. web-discovery.1.service
7. web.1.service

fleetctl Client tools use etcd Key value storage to determine what it wants to access The server And there are etcd The server runs The server . Here's how it works in CoreOS Deploy your application in the cluster .

$ fleetctl start db.1.service
$ fleetctl list-units
UNIT        LOAD    ACTIVE  SUB DESC        MACHINE
db.1.service    loaded  active  running Run db_1    9c008961.../10.0.2.15
$ fleetctl start web.1.service
$ fleetctl list-units
UNIT        LOAD    ACTIVE  SUB DESC        MACHINE
db.1.service    loaded  active  running Run db_1    9c008961.../10.0.2.15
web.1.service   loaded  active  running Run web_1   9c008961.../10.0.2.15 

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Now your program is running , But the service has not been registered etcd. Fortunately, ,fig2coreos The service file has been automatically generated for us .

$ fleetctl start db-discovery.1.service
$ fleetctl start web-discovery.1.service
$ fleetctl list-units
UNIT            LOAD    ACTIVE  SUB DESC        MACHINE
db-discovery.1.service  loaded  active  running Announce db_1   9c008961.../10.0.2.15
db.1.service        loaded  active  running Run db_1    9c008961.../10.0.2.15
web-discovery.1.service loaded  active  running Announce web_1  9c008961.../10.0.2.15
web.1.service       loaded  active  running Run web_1   9c008961.../10.0.2.15
$ etcdctl ls --recursive
/services
/services/web
/services/web/web_1
/services/db
/services/db/db_1
$ etcdctl get /services/web/web_1
{ "host": "core-03", "port": 80, "version": "52c7248a14" }
$ etcdctl get /services/db/db_1
{ "host": "core-03", "port": 3306, "version": "52c7248a14" }

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Deployment completed

That's it , done . stay Vagrant 1.5 Use Vagrant Cloud account number , You can visit your WordPress application . Here's the picture :

$ cd ~/coreos-vagrant/cluster/

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Find out which machine is listening to you 80 port ：

$ etcdctl get /services/web/web_1
{ "host": "core-03", "port": 80, "version": "52c7248a14" }

$ vagrant share core-03 --http 80==> core-03: Detecting network information for machine...
core-03: Local machine address: 192.168.65.2
core-03: Local HTTP port: 80
core-03: Local HTTPS port: disabled
==> core-03: Checking authentication and authorization...==> core-03: Creating Vagrant Share session...
core-03: Share will be at: quick-iguana-4689==> core-03: Your Vagrant Share is running! Name: quick-iguana-4689==> core-03: URL: http://quick-iguana-4689.vagrantshare.com

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Conclusion

Now you can use CoreOS Do a lot of things , But at least now you have finished the basic work , If you plan to use multi host in the production environment Coreos colony . You need to add ambassador Containers . in fact , You can go through ambassador Container connection etc The server , We will publish another blog post next week .

original text ： http://newlabs.wpengine.com/building-your-first-app-on-coreos/ author ： Lucas Carlson translation ： http://dockerone.com/article/66