目录
一.novnc简介
二.openstack中的novnc工作流程
三.源码分析
一.novnc简介
noVNC是一个支持HTML5的VNC客户端，主要作用就是与远端的vnc server进行互通，从而实现对于远端主机的控制。说白了，我们可以通过VNC客户端或者支持HTML5的浏览器访问远端安装了vnc server的服务器桌面从而进行控制。
但是vnc server发送的数据都是基于TCP之上的，而novnc处理的数据都是基于WebSocket之上的数据，所以vnc客户端无法直接与vnc server进行通讯，因此中间加入了一个代理服务器：WebSockify来实现WebSockify和TCP数据之间的转换。
二.openstack中的novnc工作流程
三.源码分析
a. 用户点击某一个虚拟机的console，请求访问通过该虚拟机的id访问该虚拟机的页面。
b. 浏览器向nova-api发送访问请求获得该虚拟机的url。
c. nova-api调用/nova/api/openstack/compute/remote_consoles.py的get_vnc_consoles()函数。
def get_vnc_console(self, req, id, body):
"""Get text console output."""
context = req.environ['nova.context']
context.can(rc_policies.BASE_POLICY_NAME)
# If type is not supplied or unknown, get_vnc_console below will cope
console_type = body['os-getVNCConsole'].get('type')
instance = common.get_instance(self.compute_api, context, id)
try:
output = self.compute_api.get_vnc_console(context,
instance,
console_type)
except exception.ConsoleTypeUnavailable as e:
raise webob.exc.HTTPBadRequest(explanation=e.format_message())
except (exception.InstanceUnknownCell,
exception.InstanceNotFound) as e:
raise webob.exc.HTTPNotFound(explanation=e.format_message())
except exception.InstanceNotReady as e:
raise webob.exc.HTTPConflict(explanation=e.format_message())
except NotImplementedError:
common.raise_feature_not_supported()
return {'console': {'type': console_type, 'url': output['url']}}上一个函数调用/nova/compute/api.py/API/get_vnc_console()函数，该函数再调用/nova/compute/rpcapi.py/ComputeAPI/get_vnc_console()函数向nova-compute进行同步RPC调用。
def get_vnc_console(self, ctxt, instance, console_type):
version = self._ver(ctxt, '4.0')
cctxt = self.router.client(ctxt).prepare(
server=_compute_host(None, instance), version=version)
return cctxt.call(ctxt, 'get_vnc_console',
instance=instance, console_type=console_type)d. nova-compute调用manager.py的get_vnc_console()函数获取该RPC消息，然后调用generate_uuid()函数生成uuid作为token；然后判断如果console_type为novnc，则生成access_url：novncproxy_base_url（nova.conf文件）+token（刚才生成的）；接下来，通过驱动driver调用libvirt的get_vnc_console()函数从获取vnc_server的详细配置信息（console：host地址（计算节点连接各个instance的内网ip地址）和端口号port）；最后将host，port和access_url连接起来生成connect_info。
/nova/compute/manager.py/ComputeManager/get_vnc_console()：
def get_vnc_console(self, context, console_type, instance):
"""Return connection information for a vnc console."""
context = context.elevated()
LOG.debug("Getting vnc console", instance=instance)
token = uuidutils.generate_uuid()
if not CONF.vnc.enabled:
raise exception.ConsoleTypeUnavailable(console_type=console_type)
if console_type == 'novnc':
# For essex, novncproxy_base_url must include the full path
# including the html file (like http://myhost/vnc_auto.html)
access_url = '%s?token=%s' % (CONF.vnc.novncproxy_base_url, token)
elif console_type == 'xvpvnc':
access_url = '%s?token=%s' % (CONF.vnc.xvpvncproxy_base_url, token)
else:
raise exception.ConsoleTypeInvalid(console_type=console_type)
try:
# Retrieve connect info from driver, and then decorate with our
# access info token
console = self.driver.get_vnc_console(context, instance)
connect_info = console.get_connection_info(token, access_url)
except exception.InstanceNotFound:
if instance.vm_state != vm_states.BUILDING:
raise
raise exception.InstanceNotReady(instance_id=instance.uuid)
return connect_info/nova/virt/libvirt/driver.py/LibvirtDriver/get_vnc_console() ：
def get_vnc_console(self, context, instance):
def get_vnc_port_for_instance(instance_name):
guest = self._host.get_guest(instance)
xml = guest.get_xml_desc()
xml_dom = etree.fromstring(xml)
graphic = xml_dom.find("./devices/graphics[@type='vnc']")
if graphic is not None:
return graphic.get('port')
# NOTE(rmk): We had VNC consoles enabled but the instance in
# question is not actually listening for connections.
raise exception.ConsoleTypeUnavailable(console_type='vnc')
port = get_vnc_port_for_instance(instance.name)
host = CONF.vnc.server_proxyclient_address
return ctype.ConsoleVNC(host=host, port=port)e. nova-api继续调用/nova/compute/api.py/API/get_vnc_console()函数，到目前为止，nova-api已经通过get_vnc_console()函数获得了connect_info，然后再次调用consoleauth的authorize_console()函数，具体实现见后文。
def get_vnc_console(self, context, instance, console_type):
"""Get a url to an instance Console."""
connect_info = self.compute_rpcapi.get_vnc_console(context,
instance=instance, console_type=console_type)
self.consoleauth_rpcapi.authorize_console(context,
connect_info['token'], console_type,
connect_info['host'], connect_info['port'],
connect_info['internal_access_path'], instance.uuid,
access_url=connect_info['access_url'])
return {'url': connect_info['access_url']}f. /nova/consoleauth/rpcapi.py/ConsoleAuthAPI/authorize_console()函数，该函数会发送RPC调用给nova-consoleauth服务，该服务继续调用/nova/consoleauth/manager.py/ConsoleAuthManager/ authorize_console()函数处理请求，具体是nova-consoleauth会将instance –> token, token –> connect_info的信息cache起来。
def authorize_console(self, context, token, console_type, host, port,
internal_access_path, instance_uuid,
access_url=None):
token_dict = {'token': token,
'instance_uuid': instance_uuid,
'console_type': console_type,
'host': host,
'port': port,
'internal_access_path': internal_access_path,
'access_url': access_url,
'last_activity_at': time.time()}
data = jsonutils.dumps(token_dict)
self.mc.set(token.encode('UTF-8'), data)
tokens = self._get_tokens_for_instance(instance_uuid)
# Remove the expired tokens from cache.
token_values = self.mc.get_multi(
[tok.encode('UTF-8') for tok in tokens])
tokens = [name for name, value in zip(tokens, token_values)
if value is not None]
tokens.append(token)
self.mc_instance.set(instance_uuid.encode('UTF-8'),
jsonutils.dumps(tokens))
LOG.info("Received Token: %(token)s, %(token_dict)s",
{'token': token, 'token_dict': token_dict})g. nova-api会将的access_url返回给浏览器，如：http://192.168.174.10:6082/spice_auto.html?token=2842a8d2-704e-4f00-967b-c4812ea68de5&title=vxlan_instance1(716e9189-fad1-4081-9bc9-aba5dd8da272)，浏览器向nova-novncproxy发送这个url，然后该服务会调用/nova/console/websocketproxy.py/TenantSocket/new_websocket_client()函数，具体该函数的实现如下讲解：文章来源：https://www.toymoban.com/news/detail-841844.html
h. nova-novncproxy服务发起RPC调用给nova-consoleauth服务，nova-consoleauth服务调用check_token函数，nova-consoleauth服务验证了这个token，将这个instance对应的connect_info返回给nova-novncproxy，最后nova-novncproxy通过connect_info中的host, port等信息，连接compute节点上的VNC Server，从而开始了proxy的工作。文章来源地址https://www.toymoban.com/news/detail-841844.html
def new_websocket_client(self):
"""Called after a new WebSocket connection has been established."""
# Reopen the eventlet hub to make sure we don't share an epoll
# fd with parent and/or siblings, which would be bad
from eventlet import hubs
hubs.use_hub()
# The nova expected behavior is to have token
# passed to the method GET of the request
parse = urlparse.urlparse(self.path)
if parse.scheme not in ('http', 'https'):
# From a bug in urlparse in Python < 2.7.4 we cannot support
# special schemes (cf: http://bugs.python.org/issue9374)
if sys.version_info < (2, 7, 4):
raise exception.NovaException(
_("We do not support scheme '%s' under Python < 2.7.4, "
"please use http or https") % parse.scheme)
query = parse.query
token = urlparse.parse_qs(query).get("token", [""]).pop()
if not token:
# NoVNC uses it's own convention that forward token
# from the request to a cookie header, we should check
# also for this behavior
hcookie = self.headers.get('cookie')
if hcookie:
cookie = Cookie.SimpleCookie()
for hcookie_part in hcookie.split(';'):
hcookie_part = hcookie_part.lstrip()
try:
cookie.load(hcookie_part)
except Cookie.CookieError:
# NOTE(stgleb): Do not print out cookie content
# for security reasons.
LOG.warning('Found malformed cookie')
else:
if 'token' in cookie:
token = cookie['token'].value
ctxt = context.get_admin_context()
rpcapi = consoleauth_rpcapi.ConsoleAuthAPI()
connect_info = rpcapi.check_token(ctxt, token=token)
if not connect_info:
raise exception.InvalidToken(token=token)
# Verify Origin
expected_origin_hostname = self.headers.get('Host')
if ':' in expected_origin_hostname:
e = expected_origin_hostname
if '[' in e and ']' in e:
expected_origin_hostname = e.split(']')[0][1:]
else:
expected_origin_hostname = e.split(':')[0]
expected_origin_hostnames = CONF.console.allowed_origins
expected_origin_hostnames.append(expected_origin_hostname)
origin_url = self.headers.get('Origin')
# missing origin header indicates non-browser client which is OK
if origin_url is not None:
origin = urlparse.urlparse(origin_url)
origin_hostname = origin.hostname
origin_scheme = origin.scheme
if origin_hostname == '' or origin_scheme == '':
detail = _("Origin header not valid.")
raise exception.ValidationError(detail=detail)
if origin_hostname not in expected_origin_hostnames:
detail = _("Origin header does not match this host.")
raise exception.ValidationError(detail=detail)
if not self.verify_origin_proto(connect_info, origin_scheme):
detail = _("Origin header protocol does not match this host.")
raise exception.ValidationError(detail=detail)
self.msg(_('connect info: %s'), str(connect_info))
host = connect_info['host']
port = int(connect_info['port'])
# Connect to the target
self.msg(_("connecting to: %(host)s:%(port)s") % {'host': host,
'port': port})
tsock = self.socket(host, port, connect=True)
# Handshake as necessary
if connect_info.get('internal_access_path'):
tsock.send(encodeutils.safe_encode(
"CONNECT %s HTTP/1.1\r\n\r\n" %
connect_info['internal_access_path']))
end_token = "\r\n\r\n"
while True:
data = tsock.recv(4096, socket.MSG_PEEK)
token_loc = data.find(end_token)
if token_loc != -1:
if data.split("\r\n")[0].find("200") == -1:
raise exception.InvalidConnectionInfo()
# remove the response from recv buffer
tsock.recv(token_loc + len(end_token))
break
if self.server.security_proxy is not None:
tenant_sock = TenantSock(self)
try:
tsock = self.server.security_proxy.connect(tenant_sock, tsock)
except exception.SecurityProxyNegotiationFailed:
LOG.exception("Unable to perform security proxying, shutting "
"down connection")
tenant_sock.close()
tsock.shutdown(socket.SHUT_RDWR)
tsock.close()
raise
tenant_sock.finish_up()
# Start proxying
try:
self.do_proxy(tsock)
except Exception:
if tsock:
tsock.shutdown(socket.SHUT_RDWR)
tsock.close()
self.vmsg(_("%(host)s:%(port)s: "
"Websocket client or target closed") %
{'host': host, 'port': port})
raise到了这里，关于openstack 之 novnc流程分析的文章就介绍完了。如果您还想了解更多内容，请在右上角搜索TOY模板网以前的文章或继续浏览下面的相关文章，希望大家以后多多支持TOY模板网！
