Reading about the starting setup, this might be the way to tell roscore to set up the right server?
export ROS_MASTER_URI=http://0.0.0.0:80/
roscore -p 80
Have you tried this? (just guessing)
@imrehg I understand, so does it mean that all local host ports are not accessible from the outside?
This might be helpful in how ros works
When a ros master is running on a specific port, different nodes register their address and topics to the rosmaster.
The problem I am facing is that I want to run a node on a different device(my laptop) while the ros master is running INSIDE the container. For my ros node to run(in my laptop), I need to set the ROS_MASTER_URI to the address /port where roscore is running(which is running in the container). That way, my ros node running in the laptop can get information of the other ros nodes that are communicating with the same ros master.
For eg. you can have a ros master running in a AWS server, while my laptop and other devices run a ros node with the same ROS_MASTER_URI pointing to the address/port of the rosmaster. This way, rosnodes can talk to eachother
$ export ROS_MASTER_URI=http://0.0.0.0:80/
$ roscore -p 80
... logging to /root/.ros/log/2ea8eec4-7fac-11e8-8e7a-f8633ff9a90c/roslaunch-12f197a-2039.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://localhost:41753/
ros_comm version 1.12.13
SUMMARY
========
PARAMETERS
* /rosdistro: kinetic
* /rosversion: 1.12.13
NODES
WARNING: ROS_MASTER_URI [http://0.0.0.0:80/] host is not set to this machine
auto-starting new master
process[master]: started with pid [2049]
ROS_MASTER_URI=http://localhost:80/
setting /run_id to 2ea8eec4-7fac-11e8-8e7a-f8633ff9a90c
process[rosout-1]: started with pid [2062]
started core service [/rosout]
The roscore just starts a new rosmaster on the localhost.
ROS_MASTER_URI specifies which rosmaster the ROS NODES should connect to,
you have to run a roscore on some place that other nodes can connect to
No, all host ports should be accessible from the outside - if the server listens on those ports and on the relevant network interfaces:
-
localhost:portmeans the device listens only locally, on the port, on the loopback interface -
0.0.0.0:portmeans the device listens on that port, on all interfaces (ie. ethernet, wifi, everything available -
ip:portmeans the device just listens on that particular IP (belonging to an interface), and that port
Okay, I understand your situation a bit better, but then the question is still:
- how are you running the master inside the container?
- as much as I can tell from the docs (at http://wiki.ros.org/ROS/Tutorials/UnderstandingNodes) ,
roscoreisMaster + rosout + parameter serverthus when you are running roscore, it will just start a master! - are all those command lines you sent above are on your laptop? We thought that’s in the container.
Based on this feedback, here are some adjusted suggestions:
- if the master is running inside the container, it seems it exposes the port 80 - but only on localhost. Change the master inside the container to expose on all interfaces? How do you run the master there? By running
roscoreinside the container as well? Because then the environment variable and command line sent above needs to be in the container start script! - on your local network device, there of course
ROS_MASTER_URIneeds to point to the actual IP or name of the device. Once the change was applied to the container, we can adjust that as well.
So what do you think about the first part above?
@imrehg I was running the rosmaster inside the container by ssh ing into it.
For the answers to the question.
- I was only running the rosmaster inside the container, and trying to access that from the outside. To clarify,
(inside the container)
roscore -p 80
(on the laptop)
export ROS_MASTER_URI=http://localhost:80
rostopic list
For the feedbacks:
- For the first feedback, I will try running as a CMD instruction in the dockerfile and see if it makes a difference.
- On the second feedback, do you mean the actual IP the IP of the host OS? for me it is a little confusing how the IP / port works with the container and the hostOS
I really appreciate you looking into this and will get back to you after applying the changes to the container.
Thanks,
This above is not quite right as much as I can tell
In the container should run:
export ROS_MASTER_URI=http://0.0.0.0:80
roscore -p 80
and on the laptop should run:
export ROS_MASTER_URI=http://<master address>:80
rostopic list
where <master address> is e.g. the device’s IP.
Not sure if this would work, but the one you wrote is definitely not on the right path.
I mean the device’s local network IP. Not sure what is the difference between “actual IP” and “IP of the host OS” is in that above. Basically the device has an IP address that is reachable from the outside (e.g. the local network), and that’s the address it needs connecting to. The container here doesn’t matter and doesn’t have its own address. All the application in this (privileged, host networking) container does is listening on certain ports. The localhost vs 0.0.0.0 difference is the same on all devices, doesn’t need to be containers.
@imrehg Thank you for clarifying on the network address on container / hostOS
Although I am not sure if we are on the same page about setting the rosmaster address on 0.0.0.0
As far as I know, It is NOT possible to start a rosmaster on 0.0.0.0 The ROS_MASTER_URI environment variable is referenced by the rosnodes(even that are running locally), not the rosmaster. The rosnodes use the variable to connect to the rosmaster.
If you run roscore -p 80 the rosmaster will still start on localhost:80
If you try running the command as you have suggested, you will see that it still launches a rosmaster on localhost:80
export ROS_MASTER_URI=http://0.0.0.0:80
roscore -p 80
The log of the command above is
$ export ROS_MASTER_URI=http://0.0.0.0:80/
$ roscore -p 80
... logging to /root/.ros/log/2ea8eec4-7fac-11e8-8e7a-f8633ff9a90c/roslaunch-12f197a-2039.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://localhost:41753/
ros_comm version 1.12.13
SUMMARY
========
PARAMETERS
* /rosdistro: kinetic
* /rosversion: 1.12.13
NODES
WARNING: ROS_MASTER_URI [http://0.0.0.0:80/] host is not set to this machine
auto-starting new master
process[master]: started with pid [2049]
ROS_MASTER_URI=http://localhost:80/
setting /run_id to 2ea8eec4-7fac-11e8-8e7a-f8633ff9a90c
If you set ROS_MASTER_URI to 0.0.0.0:80 the rosnodes will not be able to connect to the rosmaster that is running locally
Assuming we can start roscore in the container only with localhost (‘limitation’ by roscore) and we want to connect from the laptop with
export ROS_MASTER_URI=http://<master address>:80
rostopic list
Is there a easy workaround to open the ports so that they are accessible even if roscore doesn’t do the ‘right’ thing for resin?
hi @jalim it’s getting really complex to untangle things here. One thing is for sure, that ROS_MASTER_URI on your laptop is not going be much help, that is always connecting to the local device (your laptop).
Would it be possible to share your code with us, so we can take a look like that?
I’m pretty sure that the master has to be able to run on not just localhost. localhost should expose things only on the local device, and in the examples there are remote connections to the master. Thus I’m still thinking there’s a configuration issue to overcome here.
Hi @imrehg
To clarify:
In a standard use case without resin and just 2 standard ubuntu computers this is what I would do as a user of ROS:
On computer A:
roscore
on computer B
export ROS_MASTER_URI=http://:80
rostopic list
ROS_MASTER_URI corresponds to the address of computer A, no need to set it on computer A.
I lack the insight into the resin networking setup why this does not work per default with resin?
It all depends how things are set up on the resin device, are the ports exposed to the general network for example. That’s the reason we’d like to look at the code, as it’s easier to tell. W
If it’s a single-container setup (just a Dockerfile or Dockerfile.template), then the container will run with host networking, which means it should work the same way as you describe - if something listens on a port, it will be available to connect to.
If a multicontainer setup is used ( a docker-compose.yml to set up services), then the given ports need to be explicitly exposed, or host networking needs to be set explicitly.
And if it works as you describe, the master is not run with localhost, but likely the more permissive “listen on all interfaces” (ie. 0.0.0.0 setup). But again, this is not clear how things are started. From the wiki at ROS/EnvironmentVariables - ROS Wiki it says:
Great care should be taken when using localhost, as that can lead to unintended behaviors with remotely launched nodes.
Thus there’s more to consider, I think.
Just wondering, do you also have a setup that doesn’t work, that we might be able to look at and provide feedback on?
@imrehg I looked back on the issue and it turned out to be a simple configuration issue.
You simply need to set the ROS_HOSTNAME and the ROS_MASTER_URI as the local network address such as
export ROS_HOSTNAME=192.168.1.116
export ROS_MASTER_URI=http://192.168.1.116:80
Thank you for your inputs.
That’s awesome, @jalim! Thanks for letting us know.
I learned a bit about ROS as well, and looking forward seeing what will you make! 