nova分析（2）—— nova-all

nova-all是一个用来启动所有nova服务的辅助脚本，注意只是启动所有服务，不包括停止和重启等功能。

nova-all的入口在 nova.cmd.all:main ，脚本也比较简单，这儿就贴下代码了

def main():
    # 命令行参数解析，实际上命令行参数并没有使用
    config.parse_args(sys.argv)
    logging.setup("nova")
    LOG = logging.getLogger('nova.all')
    utils.monkey_patch()
    objects.register_all()
    launcher = service.process_launcher()

    # 启动API以提供Rest服务，也就是nova-api（以WSGIService方式启动）
    for api in CONF.enabled_apis:
        try:
            should_use_ssl = api in CONF.enabled_ssl_apis
            server = service.WSGIService(api, use_ssl=should_use_ssl)
            launcher.launch_service(server, workers=server.workers or 1)
        except (Exception, SystemExit):
            LOG.exception(_('Failed to load %s') % '%s-api' % api)

    # 启动s3server（基于本地文件实现S3式的存储服务）
    # 启动xvp_proxy(VNC代理，支持基于java的vnc客户端)
    # 这两个服务都是以wsgi.Server方式启动
    for mod in [s3server, xvp_proxy]:
        try:
            launcher.launch_service(mod.get_wsgi_server())
        except (Exception, SystemExit):
            LOG.exception(_('Failed to load %s') % mod.__name__)

    # 其他的服务以Service方式启动
    for binary in ['nova-compute', 'nova-network', 'nova-scheduler',
                   'nova-cert', 'nova-conductor']:

        # FIXME(sirp): Most service configs are defined in nova/service.py, but
        # conductor has set a new precedent of storing these configs
        # nova/<service>/api.py.
        #
        # We should update the existing services to use this new approach so we
        # don't have to treat conductor differently here.
        if binary == 'nova-conductor':
            topic = CONF.conductor.topic
            manager = CONF.conductor.manager
        else:
            topic = None
            manager = None

        try:
            launcher.launch_service(service.Service.create(binary=binary,
                                                           topic=topic,
                                                          manager=manager))
        except (Exception, SystemExit):
            LOG.exception(_('Failed to load %s'), binary)
    launcher.wait()