[ros-users] roscore not starting -- multiple network interfaces a problem?

Sun Feb 27 18:34:23 UTC 2011

On Sun, Feb 27, 2011 at 12:59 AM, Patrick Bouffard
<bouffard at eecs.berkeley.edu> wrote:
> Hi, I've just setup a new Ubuntu 10.10 box that will be running some
> ROS nodes, occasionally including roscore. I installed diamondback
> from debs this evening. This particular machine has a more complex
> networking setup than others I've setup before and I suspect that is
> giving me issues with running ROS.
>
> I'm pretty sure everything is setup as it ought to be in terms of my
> .bashrc (just source /opt/ros/diamondback/setup.bash). But when I run
> roscore it just hangs. After waiting awhile, after pressing Ctrl+C
> once, the following is output:

This is saying to me that something is wrong whenever something tries
to talk to the host described in the master URI.  The only network
call that occurs by this point is a call to check the existing
parameter server.

Here is a pure Python script you can use to test this behavior:

import xmlrpclib, os
s = xmlrpclib.ServerProxy(os.environ['ROS_MASTER_URI'])
s.getParam('/', '/rosdistro')

You can change the os.environ['ROS_MASTER_URI'] to use different
hostnames/IP addresses to test the behavior of the network you setup.

>
> {{{
> ^C... logging to
> /home/bouffard/.ros/log/ea02b894-424c-11e0-a499-00226bbd5586/roslaunch-lynx-3561.log
> Checking log directory for disk usage. This may take awhile.
> Press Ctrl-C to interrupt
> Done checking log file disk usage. Usage is <1GB.
>
> started roslaunch server http://lynx:52141/
> ros_comm version 1.4.4
>
> SUMMARY
> ========
>
> PARAMETERS
>  * /rosversion
>  * /rosdistro
>
> NODES
>
> auto-starting new master
> process[master]: started with pid [3576]
> ROS_MASTER_URI=http://lynx:11311/
>
> setting /run_id to ea02b894-424c-11e0-a499-00226bbd5586
> process[rosout-1]: started with pid [3589]
> started core service [/rosout]
> }}}
>
> At this point things seem to be working; roswtf returns no errors or
> warnings, I can run, e.g., rxconsole, rostopic list outputs /rosout
> and /rosout_agg, etc. But having to hit Ctrl+C is not so great.
>
> Also, without roscore running, if I run roswtf it also hangs after displaying:
>
> {{{
> bouffard at lynx:~$ roswtf
> Loaded plugin tf.tfwtf
> No package or stack in context
> ================================================================================
> Static checks summary:
>
> No errors or warnings
> ================================================================================
> }}}
>
> If I then hit Ctrl+C I get the following traceback:
>
> {{{
> ^CTraceback (most recent call last):
>  File "/opt/ros/diamondback/ros/bin/roswtf", line 35, in <module>
>    roswtf.roswtf_main()
>  File "/opt/ros/diamondback/stacks/ros_comm/utilities/roswtf/src/roswtf/__init__.py",
> line 93, in roswtf_main
>    _roswtf_main()
>  File "/opt/ros/diamondback/stacks/ros_comm/utilities/roswtf/src/roswtf/__init__.py",
> line 208, in _roswtf_main
>    master = master_online()
>  File "/opt/ros/diamondback/stacks/ros_comm/utilities/roswtf/src/roswtf/__init__.py",
> line 100, in master_online
>    master.getPid('/roswtf')
>  File "/usr/lib/python2.6/xmlrpclib.py", line 1199, in __call__
>    return self.__send(self.__name, args)
>  File "/usr/lib/python2.6/xmlrpclib.py", line 1489, in __request
>    verbose=self.__verbose
>  File "/usr/lib/python2.6/xmlrpclib.py", line 1235, in request
>    self.send_content(h, request_body)
>  File "/usr/lib/python2.6/xmlrpclib.py", line 1349, in send_content
>    connection.endheaders()
>  File "/usr/lib/python2.6/httplib.py", line 908, in endheaders
>    self._send_output()
>  File "/usr/lib/python2.6/httplib.py", line 780, in _send_output
>    self.send(msg)
>  File "/usr/lib/python2.6/httplib.py", line 739, in send
>    self.connect()
>  File "/usr/lib/python2.6/httplib.py", line 720, in connect
>    self.timeout)
>  File "/usr/lib/python2.6/socket.py", line 554, in create_connection
>    sock.connect(sa)
>  File "<string>", line 1, in connect
> KeyboardInterrupt
> bouffard at lynx:~$
> }}}

My theory is that this is the same pause as described above.  It's
hanging in an xmlrpc call to the master (aka Parameter Server).

> Just to check that it wasn't something in the latest diamondback
> release candidate, I dist-upgrade'd and tried these same commands on
> another couple machines (that have been running some version of ROS
> for awhile and are similarly configured, Ubuntu 10.0, diamondback
> debs) with no problems.
>
> Based on the roswtf traceback and the main weirdness of the current
> box being its network config (it has three wired network interfaces),
> I'm suspecting it has something to do with that. However, I still see
> the same behaviour if I sudo ifdown all the interfaces besides lo.
>
> I'm not a networking expert but I noticed on the EnvironmentVariables
> wiki page: ".. ROS components bind to all available network
> interfaces.". Could this have something to do with my issues?

You can change this behavior by setting ROS_IP or ROS_HOSTNAME.  Using
either tells a particular process to bind to a specific interface.
All evidence thus far is that something is wrong with how the 'lynx'
hostname is configured.

 - Ken

> Here's the output of ifconfig -a in case that helps:
>
> {{{
> bouffard at lynx:~$ ifconfig -a
> eth1      Link encap:Ethernet  HWaddr xx:xx;xx:xx:xx:xx
>          inet addr:128.32.43.208  Bcast:128.32.43.255  Mask:255.255.255.0
>          inet6 addr: fe80::218:8bff:fe74:766d/64 Scope:Link
>          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>          RX packets:1066 errors:0 dropped:0 overruns:0 frame:0
>          TX packets:504 errors:0 dropped:0 overruns:0 carrier:0
>          collisions:0 txqueuelen:1000
>          RX bytes:329324 (329.3 KB)  TX bytes:116257 (116.2 KB)
>          Interrupt:17
>
> eth2      Link encap:Ethernet  HWaddr xx:xx;xx:xx:xx:xx
>          inet addr:192.168.1.1  Bcast:192.168.1.255  Mask:255.255.255.0
>          inet6 addr: fe80::e291:f5ff:fe94:cc3/64 Scope:Link
>          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>          RX packets:1264 errors:0 dropped:0 overruns:0 frame:0
>          TX packets:1342 errors:0 dropped:0 overruns:0 carrier:0
>          collisions:0 txqueuelen:1000
>          RX bytes:78005 (78.0 KB)  TX bytes:67277 (67.2 KB)
>          Interrupt:17 Base address:0xef00
>
> eth3      Link encap:Ethernet  HWaddr xx:xx;xx:xx:xx:xx
>          inet addr:10.32.43.1  Bcast:10.32.43.255  Mask:255.255.255.0
>          inet6 addr: fe80::222:6bff:febd:5586/64 Scope:Link
>          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>          RX packets:235591 errors:0 dropped:0 overruns:0 frame:0
>          TX packets:451507 errors:0 dropped:0 overruns:0 carrier:0
>          collisions:0 txqueuelen:1000
>          RX bytes:17233068 (17.2 MB)  TX bytes:629352191 (629.3 MB)
>          Interrupt:16 Base address:0x2e00
>
> lo        Link encap:Local Loopback
>          inet addr:127.0.0.1  Mask:255.0.0.0
>          inet6 addr: ::1/128 Scope:Host
>          UP LOOPBACK RUNNING  MTU:16436  Metric:1
>          RX packets:8526 errors:0 dropped:0 overruns:0 frame:0
>          TX packets:8526 errors:0 dropped:0 overruns:0 carrier:0
>          collisions:0 txqueuelen:0
>          RX bytes:817773 (817.7 KB)  TX bytes:817773 (817.7 KB)
> }}}
>
> eth1 is the connection to the internet, eth2 is a crossover cable to
> another machine, and eth3 connected to a private subnet. Iptables is
> configured to allow machines on the 10.32.43.x subnet to access the
> internet via eth1. It's possible something I did in setting that up
> had the side-effect of messing with ROS, as I said I'm no networking
> expert. Hopefully one of you is! :)
>
> Thanks,
> Pat
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