collective.hostout 1.0a3

What does it do?

If you are new to remote application management, hostout can help you to deploy your first site in minutes. Hostout is compatible with Plone, django, or any other buildout based environment.

Hostout is a zc.buildout recipe Hostout generates a script which logs into your remote host(s) and performs preset and customizable commands. e.g.

$ bin/hostout productionserver deploy

$ bin/hostout server1 server2 supervisorctl restart instance1

$ bin/hostout all cmd ls -al

$ bin/hostout staging mylocalfabriccommand

How does it do that?

Commands can easily be added from a local fabric script, hostout command plugins or just the builtin commands to help you bootstrap and deploy your buildout to remote hosts.

Why is hostout awesome?

Managing multiple environments can be a real pain and a barrier to development. Hostout puts all of the settings for all of your environments in an easy-to-manage format.

Installing hostout

First follow the instructions and to get your development buildout running on your development machine. You can add this recipe to a buildout for Plone, django or any other buildout based environment.

Add the collective.hostout part to your development buildout.

>>> write('buildout.cfg',
... """
... [buildout]
... parts = host1
...
... [host1]
... recipe = collective.hostout
... host = 127.0.0.1:10022
... user = root
... password = root
... path = /usr/local/plone/host1
... """ % globals())

If you don’t include your password you will be prompted for it later.

Next rerun your buildout to install the hostout script in your buildout bin directory

>>> print system('bin/buildout -N')
Installing host1.
Generated script '/sample-buildout/bin/hostout'.

The generated script is run with a command and host(s) as arguments

>>> print system('bin/hostout')
cmdline is: bin/hostout host1 [host2...] [all] cmd1 [cmd2...] [arg1 arg2...]
Valid hosts are: host1

Each host refers to the name of a part with recipe=collective.hostout in your buildout. Each host corresponds to a host and remote path which is the default location for commands to act on.

>>> print system('bin/hostout host1')
cmdline is: bin/hostout host1 [host2...] [all] cmd1 [cmd2...] [arg1 arg2...]
Valid commands are:
   bootstrap        : Install python and users needed to run buildout
   buildout         : Run the buildout on the remote server
   deploy           : predeploy, uploadeggs, uploadbuildout, buildout and then postdeploy
   postdeploy       : Perform any final plugin tasks
   predeploy        : Install buildout and its dependencies if needed. Hookpoint for plugins
   setaccess        : setup password access for users
   setowners        : Ensure ownership and permissions are correct on buildout and cache
   run              : Execute cmd on remote as login user
   sudo             : Execute cmd on remote as root user
   uploadbuildout   : Upload buildout pinned to local picked versions + uploaded eggs
   uploadeggs       : Any develop eggs are released as eggs and uploaded to the server
<BLANKLINE>

>>> print system('bin/hostout host1 run pwd')
Hostout: Running command 'run' from '.../fabfile.py'
Logging into the following hosts as root:
    127.0.0.1
[127.0.0.1] run: sh -c "cd /usr/local/plone/host1 && pwd"
[127.0.0.1] out: CMD RECIEVED
Done.

Definitions

buildout

zc.buildout is a tool for creating an isolated environment for running applications. It is controlled by a configuration file(s) called a buidout file.

buildout recipe

A buildout file consists of parts each of which has a recipe which is in charge of installing a particular piece of softare.

deploy

Take a an application you are developing and move it to a host server for use. Often deployment will be to a staging location for limited use in testing or production for mainstream use. Production, staging and development often have different but related to buildouts and could involve different numbers of hosts for each.

host

In the context of this document this a machine or VPS running linux which you would like to deploy your application to.

fabric file

see fabric

Using builtin deploy command

Often we have a buildout installed and working on a development machine and we need to get it working on one or many hosts quickly and easily.

First you will need a linux host. You’ll need a linux with ssh access and sudo access. VPS and cloud hosting is now cheap and plentiful with options as low as $11USD a month. If you’re not sure, pick a pay per hour option pre-configured with Ubuntu and give it a go for example rackspacecloud or amazon EC2.

Next you need a production buildout for your application. There are plenty available whether it be for Plone, grok, django, BFG, pylons. Often a buildout will come in several files, one for development and one for production. Just remember that to get the best performance you will need to understand your buildout.

For this example we’ve added a development egg to our buildout as well.

>>> mkdir('example')

>>> write('example', 'example.py',
... """
... def run():
...    print "all your hosts are belong to us!!!"
...
... """)

>>> write('example', 'setup.py',
... """
... from setuptools import setup
...
... setup(
...     name = "example",
...     entry_points = {'default': ['run = example:run']},
...     )
... """)

>>> write('buildout.cfg',
... """
... [buildout]
... parts = example host1
... develop = example
...
... [example]
... recipe = zc.recipe.egg
... eggs = example
...
... [host1]
... recipe = collective.hostout
... host = 127.0.0.1:10022
... user = root
... password = root
...
... """ )
>>> print system('bin/buildout -N')
Develop: '.../example'
Uninstalling host1.
Installing example.
Installing host1.

Hostout will record the versions of eggs in a local file

>>> print open('hostoutversions.cfg').read()
[versions]
collective.hostout = 0.9.4
<BLANKLINE>
# Required by collective.hostout 0.9.4
Fabric = ...

The deploy command will login to your host and setup a buildout environment if it doesn’t exist, upload and installs the buildout. The deploy command is actually five commands

predeploy

Bootstrap the server if needed. Create needed users, groups and set permissions and passwordless access

uploadeggs

Any develop eggs are released as eggs and uploaded to the server

uploadbuildout

A special buildout is prepared referencing uploaded eggs and all other eggs pinned to the local picked versions

buildout

Run the buildout on the remote server

postdeploy

Perform any final plugin tasks

>>> print system('bin/hostout host1 deploy')
    running clean
    ...
    creating '...example-0.0.0dev_....egg' and adding '...' to it
    ...
    Hostout: Running command 'predeploy' from '.../collective.hostout/collective/hostout/fabfile.py'
    ...
    Hostout: Running command 'uploadeggs' from '.../collective.hostout/collective/hostout/fabfile.py'
    Hostout: Preparing eggs for transport
    Hostout: Develop egg /sample-buildout/example changed. Releasing with hash ...
    Hostout: Eggs to transport:
        example = 0.0.0dev-...
    Hostout: Wrote versions to /sample-buildout/host1.cfg
    ...
    Hostout: Running command 'uploadbuildout' from '.../collective.hostout/collective/hostout/fabfile.py'
    ...
    Hostout: Running command 'buildout' from '.../collective/hostout/fabfile.py'
    ...
    Hostout: Running command 'postdeploy' from '.../collective.hostout/collective/hostout/fabfile.py'
    ...

We now have a live version of our buildout deployed to our host

The buildout file used on the host pins pins the uploaded eggs

>>> print open('host1.cfg').read()
[buildout]
develop =
eggs-directory = /var/lib/plone/buildout-cache/eggs
versions = versions
newest = true
extends = buildout.cfg hostoutversions.cfg
download-cache = /var/lib/plone/buildout-cache/downloads
<BLANKLINE>
[versions]
example = 0.0.0dev-...

Using command plugins

You use commands others have made via the extends option. Name a buildout recipe egg in the extends option and buildout will download and merge any fabfiles and other configuration options from that recipe into your current hostout configuration. The following are examples of builtin plugins others are available on pypi.

see hostout.cloud, hostout.supervisor, hostout.ubuntu or hostout.mrdeveloper for examples.

Adding your own commands

Hostout uses fabric files. Fabric is any easy way to write python that colls commands on a host over ssh. You can create your own fabric files as follows:

>>> write('fabfile.py',"""
... def echo(cmdline1):
...    hostout = get('hostout')
...    bin = "%s/bin" % hostout.getRemoteBuildoutPath()
...    option1 = hostout.options['option1']
...    run("echo '%s %s'" % (option1, cmdline1) )
... """)

Reference this file in the fabfiles option of your hostout part.

>>> write('buildout.cfg',
... """
... [buildout]
... parts = host1
...
... [host1]
... recipe = collective.hostout
... host = 127.0.0.1:10022
... fabfiles = fabfile.py
... option1 = buildout
... user = root
... password = root
...
... """ )

>>> print system('bin/buildout -N')
Uninstalling host1.
Uninstalling example.
Uninstalling _mr.developer.
Installing host1.

>>> print system('bin/hostout host1 echo "is cool"')
Hostout: Running command 'echo' from 'fabfile.py'
Logging into the following hosts as root:
    127.0.0.1
[127.0.0.1] run: echo 'buildout is cool'
[127.0.0.1] out: CMD RECIEVED
Done.

Sharing hostout options

For more complicated arrangements you can use the extends value to share defaults between multiple hostout definitions

>>> write('buildout.cfg',
... """
... [buildout]
... parts = prod staging
...
... [hostout]
... recipe = collective.hostout
... password = blah
... user = root
... identity-file = id_dsa.pub
... pre-commands =
...    ${buildout:directory}/bin/supervisorctl shutdown || echo 'Unable to shutdown'
... post-commands =
...    ${buildout:directory}/bin/supervisord
... effective-user = plone
... include = config/haproxy.in
...
...
... [prod]
... recipe = collective.hostout
... extends = hostout
... host = localhost:10022
... buildout =
...    config/prod.cfg
... path = /var/plone/prod
...
... [staging]
... recipe = collective.hostout
... extends = hostout
... host = staging.prod.com
... buildout =
...    config/staging.cfg
... path = /var/plone/staging
...
... """ % globals())

>>> print system('bin/buildout -N')
    Uninstalling host1.
    Installing hostout.
    Installing staging.
    Installing prod.

#>>> print system(‘bin/hostout deploy’) Invalid hostout hostouts are: prod staging

Making a hostout plugin

Hostout plugins are setuptools packages that have a zc.buildout recipe and a fabfile. The recipe is used to set defaults which will later get passed into the fabric environment. The fabric fabfile has to have an entrypoint in your setup.py file so hostout can find it. e.g.

>>>    entry_points = {'zc.buildout': ['default = collective.hostout:Recipe',],
...                    'fabric': ['fabfile = collective.hostout.fabfile']
...                    },

Using hostout with a python2.4 buildout

Hostout itself requires python2.6. However it is possible to use hostout with a buildout that requires python 2.4 by using buildout’s support for different python interpretters.

>>> write('buildout.cfg',
... """
... [buildout]
... parts = host1
...
... [host1]
... recipe = collective.hostout
... host = 127.0.0.1:10022
... python = python26
...
... [python26]
... executalble = /path/to/your/python2.6/binary
...
... """ )

or alternatively if you don’t want to use your local python you can get buildoit to build it for you.

>>> write('buildout.cfg',
... """
... [buildout]
... parts = host1
...
... [host1]
... recipe = collective.hostout
... host = 127.0.0.1:10022
... python = python26
...
... [python26]
... recipe = zc.recipe.cmmi
... url = http://www.python.org/ftp/python/2.6.1/Python-2.6.1.tgz
... executable = ${buildout:directory}/parts/python/bin/python2.6
... extra_options=
...    --enable-unicode=ucs4
...    --with-threads
...    --with-readline
...
... """ )

Detailed Hostout Options

host

the IP or hostname of the host to deploy to. by default it will connect to port 22 using ssh. You can override the port by using hostname:port

user

The user which hostout will attempt to login to your host as. Will read a users ssh config to get a default.

password

The password for the login user. If not given then hostout will ask each time.

identity-file

A public key for the login user.

extends

Specifies another part which contains defaults for this hostout

fabfiles

Path to fabric files that contain commands which can then be called from the hostout script. Commands can access hostout options via hostout.options from the fabric environment.

Todo list

• import fabfiles so they don’t produce warnings

• use decorators for picking user for commands instead of initcommand hack

• properly support inheritance and scope for command plugins

• plugins for database handling including backing up, moving between development, staging and production regardless of location.

• Integrate with SCM to tag all parts so deployments can be rolled back.

• Handle basic rollback when no SCM exists, for instance when buildout fails.

• Help deploy DNS settings, possibly by hosting company specific plugins

• Incorporate unified installer environment setup scripts directly.

• Support firewalled servers by an optional tunnel back to a client side web proxy.

• Explore ways to make an even easier transition from default plone install to fully hosted site.

Credits

Dylan Jay ( software at pretaweb dot com )

Release History