Evaluation for ProgDTN (formerly CADR)

ARP Cache overflow problem in big simulations

When simulating a high number of nodes, it occasionally happens, that the ARP table overflows. A workaround is, to increase the threshold for the garbage collector in the kernel. Because this a kernel thing, it has to be done on the host, and not inside of the container. A more detailed writeup written here: (https://www.cyberciti.biz/faq/centos-redhat-debian-linux-neighbor-table-overflow/).

The thresholds can be set in /etc/sysctl.conf:

sudo -s
echo "
## works best with <= 500 client computers
# Force gc to clean-up quickly
net.ipv4.neigh.default.gc_interval = 3600

# Set ARP cache entry timeout
net.ipv4.neigh.default.gc_stale_time = 3600

# Setup DNS threshold for arp
net.ipv4.neigh.default.gc_thresh3 = 4096
net.ipv4.neigh.default.gc_thresh2 = 2048
net.ipv4.neigh.default.gc_thresh1 = 1024" >> /etc/sysctl.conf

sysctl -p
exit

sysctl net.ipv4.neigh.default.gc_thresh1
sysctl net.ipv4.neigh.default.gc_thresh2
sysctl net.ipv4.neigh.default.gc_thresh3

MACI: Headless and GUI worker

This worker is available with a gui to be used during experiment development as well as a headless version for lightweight experiment runs.

Build images

docker build -t umrds/cadr-evaluation -f Dockerfile .
# or
docker-compose build core

Standalone Quickstart

Although this container is intended to be used with MACI, it as a standalone container for debugging. To work with the CORE GUI, the host needs to run an X11 server.

Setup X11 on macOS

1. Install XQuartz, e.g. brew cask install xquartz
2. Configure X to allow connections from network clients (XQuartz -> Settings -> Security -> Allow Network Clients)

Setup X11 on lightdm (Ubuntu 16)

Allow connections from network clients. Add to /etc/lightdm/lightdm.conf:

[SeatDefaults]
xserver-allow-tcp=true

... and restart lightdm using sudo restart lightdm.

Setup X11 on gdm3 (Ubuntu 18)

Allow connections from network clients. Add to /etc/gdm3/custom.conf:

[security]
DisallowTCP=false

Load ebtables kernel-module

sudo modprobe ebtables

Start GUI

Add the remote docker host to the xhost access control list (xhost +<DOCKER_HOST_IP>) OR disable the access control list (xhost +).

The container can be started adding your IP to the DISPLAY variable:

docker run --rm --privileged -v /lib/modules:/lib/modules -it --cap-add=NET_ADMIN -e DISPLAY=<IP>:0 umrds/cadr-evaluation
# or
DISPLAY=<IP>:0 docker-compose run core

Hint: Docker for Mac users can use the special hostname docker.for.mac.localhost.

Attention: Linux sometimes uses other Display numbers than 0. Checkout your Display using echo $DISPLAY