Tcpkali

tcpkali is a high performance TCP and WebSocket load generator and sink.

Test concurrent TCP connections between two machines

Host + Client VM setup

NOTE: Run the following commands on both the Host and the Client VMs/instances.

• Install tcpkali:

$ sudo yum update -y
$ sudo yum install -y autoconf automake libtool bison flex gcc-c++ ncurses-devel git
$ git clone https://github.com/satori-com/tcpkali.git
$ cd tcpkali/
$ test -f configure || autoreconf -iv
$ ./configure
$ make
$ sudo make install

• Install socat:

$ sudo yum install -y socat

• Change kernel settings:

$ sudo echo 1 >/proc/sys/net/ipv4/tcp_tw_reuse

• Add the following lines to the /etc/security/limits.conf file:

@wheel           soft    nofile          6000
@wheel           hard    nofile          65335
<pre>
Then,
<pre>
$ sudo sysctl -p
$ ulimit -a
$ ulimit -Sn  # [soft] maximum number of open file descriptors
$ ulimit -Hn  # [hard] maximum number of open file descriptors

Host VM setup

NOTE: Run the following commands only on the Host VM/instance.

• Start up socat (in the background):

$ sudo socat -v tcp-l:443,fork exec:'/bin/cat' &

• Watch for "ESTABLISHED" connections on the host:

$ export TCP_LOGFILE=tcp.log
while true; do
  netstat -an | grep "ESTABLISHED" | grep -v :22 | \
  echo -e "$(date +%s)\t$(wc -l)" | tee -a ${TCP_LOGFILE}; sleep 1;
done

Client VM setup

NOTE: Run the following commands only on the Client VM/instance.

• Run tcpkali on Client VM:

$ export HOST_IP=x.x.x.x
$ export HOST_PORT=443
$ export CONNECTIONS=1000  # Connections to keep open to the destination(s)
$ export WORKERS=2         # Number of parallel threads to use
$ export DURATION=1000     # Exit after the specified amount of time (in seconds)

#  --latency-connect            Measure TCP connection establishment latency
#  --latency-first-byte         Measure time to first byte latency
#  --latency-marker <string>    Measure latency using a per-message marker
#  --latency-marker-skip <N>    Ignore the first N occurrences of a marker
#  --latency-percentiles <list> Report latency at specified percentiles
$ export LATENCY_OPTION=--latency-connect

$ tcpkali ${HOST_IP}:${HOST_PORT} \
    --connections=${CONNECTIONS} \
    --workers=${WORKERS} \
    --duration=${DURATION} \
    ${LATENCY_OPTION} \
    --verbose=3  # [0..3]

External links

• Official website