Question about failing to create v-link

[RangoShang]

Hi,
When I was running the code, I got the problem that the v-links can not be created. When I checkt the log I got this.

vlinks:

• dest_node: pop2
  dest_vnf: vnf_fw1
  emu_debug_info: '"HTTPConnectionPool(host=''localhost'', port=8080): Max retries
  exceeded with url: /stats/flowentry/add (Caused by NewConnectionError(''<urllib3.connection.HTTPConnection
  object at 0x7f6014169f60>: Failed to establish a new connection: [Errno 111]
  Connection refused'',))"

  '
  src_node: pop0
  src_vnf: vnf_user

• dest_node: pop9
  dest_vnf: vnf_web
  emu_debug_info: '"HTTPConnectionPool(host=''localhost'', port=8080): Max retries
  exceeded with url: /stats/flowentry/add (Caused by NewConnectionError(''<urllib3.connection.HTTPConnection
  object at 0x7f60140ef9e8>: Failed to establish a new connection: [Errno 111]
  Connection refused'',))"

  '
  src_node: pop2
  src_vnf: vnf_fw1
  vnfs:

• image: '{"image":"placement-apache-img", "network":"(id=input,ip=99.0.0.2/24)"}'
  name: vnf_web
  node: pop9

• image: '{"image":"placement-fw1-img", "network":"(id=input,ip=88.0.0.2/24),(id=output,ip=99.0.0.1/24)"}'
  name: vnf_fw1
  node: pop2

• image: '{"image":"placement-user-img", "network":"(id=output,ip=88.0.0.1/24)"}'
  name: vnf_user
  node: pop0
  time: 2021-12-10_06-47-06
  And then, I check that the port of 8080 is not open. However, I don't know what is the port used for. How could I fix this problem? It would be appreciated to tackle this problem.

[stefanbschneider]

Hi, I have to admit that I haven't used placement-emulation in years myself, so I don't know the answer from the top of my head.

Port 8080 is an alternative to the standard port 80, but I am not sure where/why/if we have used that in placement-emulation. When searching the code for "8080", I didn't find anything.

Did you try the emulation and testing steps described here: https://github.com/CN-UPB/placement-emulation/wiki/emulation

Maybe that helps with debugging the issue. If you make progress or come up with another issue, feel free to comment again - maybe I'll be of more help then.

[RangoShang]

Thanks a lot for helping me. I found that the problem is that the ryu controller is not opened rightly. And the port is used in the controller restful API. After I restart the ryu controller, the problem is solved.
However when I was testing the program, I could not let the containernet CLI show up, so I have to get into the docker to make RTT test. After I terminate the daemon process, the links and nodes are shut down. So could you tell me how to get the container CLI with the daemonizing vim-emu? That would be appreciated.

[stefanbschneider]

I am not sure, I fully understand your situation and problem - partly also because I haven't used containernet, vim-emu, and placment-emulation for quite while.
Did you install vim-emu and containernet using the bare-metal installation (option 1) or using nested Docker containers (option 2)?

Either way, you need access to a terminal where everything is installed, i.e., locally (for bare metal) or on the Docker container (for option 2). Inside that terminal you should run the script to start placement emulation and containernet in the forground: https://github.com/CN-UPB/placement-emulation/wiki/emulation#start-a-topology
This should give you the containernet CLI. For vim-emu, use a second terminal.

If you have started the containernet script in the background, you can re-attach to it like this: https://unix.stackexchange.com/a/31830/203270 (I haven't tried)