neutron-server服务启动流程-基于mitaka版本

桃扇骨 2022-07-03 18:21 269阅读 0赞

1、neutron 启动命令为：

/usr/bin/python2.7 /usr/bin/neutron-server --config-file /etc/neutron/neutron.conf --log-file=/var/log/neutron/server.log --config-file /etc/neutron/plugins/ml2/ml2_conf.ini

其中cat /usr/bin/neutron-server

#!/usr/bin/python2.7
    # PBR Generated from u'console_scripts'
    
    import sys
    
    from neutron.cmd.eventlet.server import main
    
    
    if __name__ == "__main__":
    sys.exit(main())

2、进入neutron代码中

*  首先是neutron/cmd/eventlet/server/\_\_init\_\_.py 的main函数

def main():
        server.boot_server(_main_neutron_server)

*  neutron/server/\_\_init\_\_.py，读取配置设置日志

def boot_server(server_func):
        # the configuration will be read into the cfg.CONF global data structure
        config.init(sys.argv[1:])
        config.setup_logging()
        config.set_config_defaults()
        if not cfg.CONF.config_file:
            sys.exit(_("ERROR: Unable to find configuration file via the default"
                       " search paths (~/.neutron/, ~/, /etc/neutron/, /etc/) and"
                       " the '--config-file' option!"))
        try:
            server_func()
        except KeyboardInterrupt:
            pass
        except RuntimeError as e:
            sys.exit(_("ERROR: %s") % e)

*  neutron/cmd/eventlet/server/\_\_init\_\_.py 的\_main\_neutron\_server函数

def _main_neutron_server():
        if cfg.CONF.web_framework == 'legacy':
            wsgi_eventlet.eventlet_wsgi_server()
        else:
            wsgi_pecan.pecan_wsgi_server()

*  neutron/server/wsgi\_pecan.py的pecan\_wsgi\_server函数

def pecan_wsgi_server():
        LOG.info(_LI("Pecan WSGI server starting..."))
        application = pecan_app.setup_app()
        neutron_api = service.run_wsgi_app(application)
        wsgi_eventlet.start_api_and_rpc_workers(neutron_api)

其中application得到是关于http请求的一些policy、context、quota等的检验关于pecan起restful api的例子可以查看

> [https://segmentfault.com/a/1190000003810294][https_segmentfault.com_a_1190000003810294]

通过以下方法启动neutron-server监听端口及其wsgi应用

neutron_api = service.run_wsgi_app(application)

接下来开始加载neutron的plugins：

*  neutron/server/wsgi\_eventlet.py 的start\_api\_and\_rpc\_workers函数

def start_api_and_rpc_workers(neutron_api):
        pool = eventlet.GreenPool()
    
        api_thread = pool.spawn(neutron_api.wait)
    
        try:
            neutron_rpc = service.serve_rpc()
        except NotImplementedError:
            LOG.info(_LI("RPC was already started in parent process by "
                         "plugin."))
        else:
            rpc_thread = pool.spawn(neutron_rpc.wait)
    
            plugin_workers = service.start_plugin_workers()
            for worker in plugin_workers:
                pool.spawn(worker.wait)
    
            # api and rpc should die together. When one dies, kill the other.
            rpc_thread.link(lambda gt: api_thread.kill())
            api_thread.link(lambda gt: rpc_thread.kill())
    
        pool.waitall()

其中neutron/service.py serve\_rpc函数

def serve_rpc():
        plugin = manager.NeutronManager.get_plugin()
        service_plugins = (
            manager.NeutronManager.get_service_plugins().values())
            ...
            ...
            ...
        try:
            # passing service plugins only, because core plugin is among them
            rpc = RpcWorker(service_plugins)
            ...
            ...
            ...
            launcher = common_service.ProcessLauncher(cfg.CONF, wait_interval=1.0)
            launcher.launch_service(rpc, workers=cfg.CONF.rpc_workers)
            if (cfg.CONF.rpc_state_report_workers > 0 and
                plugin.rpc_state_report_workers_supported()):
                rpc_state_rep = RpcReportsWorker([plugin])
                LOG.debug('using launcher for state reports rpc, workers=%s',
                          cfg.CONF.rpc_state_report_workers)
                launcher.launch_service(
                    rpc_state_rep, workers=cfg.CONF.rpc_state_report_workers)
    
            return launcher
        ...
        ...
        ...

其中class NeutronManager(object)类的\_\_init\_\_函数中通过函数  
self.\_load\_service\_plugins()从配置文件中得到service\_plugins的值，并赋值给self.serivce\_plugins

/etc/neutron/neutron.conf [DEFAULT] service_plugins=xxxx

回到start\_api\_and\_rpc\_workers函数接着即会启动相应配置文件的子进程数，执行wait操作

[https_segmentfault.com_a_1190000003810294]: https://segmentfault.com/a/1190000003810294