def install_packages():
    """
    Install a set of baseline packages and configure where necessary
    """

    if env.verbosity:
        print env.host, "INSTALLING & CONFIGURING NODE PACKAGES:"
    #Get a list of installed packages
    p = run("dpkg -l | awk '/ii/ {print $2}'").split('\n')
    
    #Remove apparmor - TODO we may enable this later
    if env.overwrite or not server_state('apparmor-disabled') and 'apparmor' in p:
        with settings(warn_only=True):
            sudo('/etc/init.d/apparmor stop')
            sudo('update-rc.d -f apparmor remove')
            set_server_state('apparmor-disabled')

    #The principle we will use is to only install configurations and packages
    #if they do not already exist (ie not manually installed or other method)
    env.installed_packages[env.host] = []
    role = env.role_lookup[env.host_string]
    packages = get_packages()
    for package in packages:
        if not package in p:
            install_package(package)
            if env.verbosity:
                print ' * installed',package
            env.installed_packages[env.host].append(package)
    if env.overwrite or env.installed_packages[env.host]: #always store the latest complete list
        set_server_state('packages_installed', packages)
        env.installed_packages[env.host] = packages

    if env.overwrite and 'apache2' in env.installed_packages[env.host]: 
            #some sensible defaults -might move to putting this config in a template
            sudo("rm -f /etc/apache2/sites-enabled/000-default")
            sed('/etc/apache2/apache2.conf',before='KeepAlive On',after='KeepAlive Off',use_sudo=True, backup='')
            sed('/etc/apache2/apache2.conf',before='StartServers          2', after='StartServers          1', use_sudo=True, backup='')
            sed('/etc/apache2/apache2.conf',before='MaxClients          150', after='MaxClients          100', use_sudo=True, backup='')
            for module in env.APACHE_DISABLE_MODULES:
                sudo('rm -f /etc/apache2/mods-enabled/%s*'% module)
    #Install base python packages
    #We'll use easy_install at this stage since it doesn't download if the package
    #is current whereas pip always downloads.
    #Once both these packages mature we'll move to using the standard Ubuntu packages
    if (env.overwrite or not server_state('pip-venv-wrapper-installed')) and 'python-setuptools' in packages:
        sudo("easy_install virtualenv")
        sudo("easy_install pip")
        sudo("easy_install virtualenvwrapper")
        if env.verbosity:
            print " * easy installed pip, virtualenv, virtualenvwrapper"
        set_server_state('pip-venv-wrapper-installed')
    if not contains("/home/%s/.profile"% env.user,"source /usr/local/bin/virtualenvwrapper.sh"):
        append("/home/%s/.profile"% env.user, "export WORKON_HOME=$HOME/env")
        append("/home/%s/.profile"% env.user, "source /usr/local/bin/virtualenvwrapper.sh")

    #cleanup after easy_install
    sudo("rm -rf build")
Install a set of baseline packages and configure where necessary