[Tutorial] An example of using juju to deploy cloud services

Before you get started with juju, please refer to the official documens
https://juju.ubuntu.com/docs/getting-started.html
https://juju.ubuntu.com/docs/user-tutorial.html

P.S: When you lunch an instance, be careful about the instance type. Except t1.micro, others will charge you money~~
I strongly suggest to add parameter after juju bootstrap and deploy command as follows:

--constraints "instance-type=m1.micro"

or execute this command:
> juju set-constraints instance-type=t1.micro
For more info about this, please check out this document:
https://juju.ubuntu.com/docs/constraints.html

My environment is using EC2.
> vi .juju/environment.yaml

environments:
  sample:
    type: ec2
    access-key: << your access key >>
    secret-key: << your secret key >>
    control-bucket: juju-0f3b4bce2d944893a74967016c98b903
    admin-secret: 0d748130374946babe1f2531d77620d0
    default-series: precise
    ssl-hostname-verification: true

When you prepare your .juju/environment.yaml ready, you are able to do the following steps to try juju:
> juju bootstrap
> juju deploy wordpress
> juju deploy mysql
> juju add-relation mysql wordpress
> juju expose wordpress

After executing above commands, we can use "juju status" to see what we have now on Amazon EC2:
> juju status
2012-06-11 09:00:26,558 INFO Connecting to environment...
2012-06-11 09:00:43,657 INFO Connected to environment.
machines:
  0:
    agent-state: running
    dns-name: ec2-23-22-111-234.compute-1.amazonaws.com
    instance-id: i-30fa4a49
    instance-state: running
  1:
    agent-state: running
    dns-name: ec2-50-17-117-72.compute-1.amazonaws.com
    instance-id: i-b055eac9
    instance-state: running
  2:
    agent-state: running
    dns-name: ec2-23-22-205-88.compute-1.amazonaws.com
    instance-id: i-de52eda7
    instance-state: running
services:
  mysql:
    charm: cs:precise/mysql-2
    relations:
      db:
      - wordpress
    units:
      mysql/0:
        agent-state: started
        machine: 2
        public-address: ec2-23-22-205-88.compute-1.amazonaws.com
  wordpress:
    charm: cs:precise/wordpress-1
    exposed: true
    relations:
      db:
      - mysql
    units:
      wordpress/0:
        agent-state: started
        machine: 1
        open-ports:
        - 80/tcp
        public-address: ec2-50-17-117-72.compute-1.amazonaws.com
2012-06-11 09:01:18,809 INFO 'status' command finished successfully

From now on, we can check EC2 dashboard and see what instances are there ( it will be the same as the result of "juju status")

Because we do "expose" for wordpress, we have a public address ( ec2-50-17-117-72.compute-1.amazonaws.com) and it looks like as below:

Once you are done with an juju deployment, you need to terminate all running instances in order to stop paying for them.
> juju destroy-environment
WARNING: this command will destroy the 'sample' environment (type: ec2).
This includes all machines, services, data, and other resources. Continue [y/N]y
2012-06-11 09:53:03,181 INFO Destroying environment 'sample' (type: ec2)...
2012-06-11 09:53:10,018 INFO Waiting on 3 EC2 instances to transition to terminated state, this may take a while
2012-06-11 09:53:53,257 INFO 'destroy_environment' command finished successfully