WARNING: /proc/sys/net/core/somaxconn is set to the lower value of 128.

[milliorn]

WARNING: The TCP backlog setting of 511 cannot be enforced because /proc/sys/net/core/somaxconn is set to the lower value of 128.

Found a link with this issue being discussed.

redis/docker-library-redis#35

The warning is found in the second line in this picture.

[horsecoin]

Looks Like your redis is working somewhat, the answer is right in your terminal, all you have to do is open another terminal window & log into redis with root (with bash) and then run the command: echo never > /sys/kernel/mm/transparent_hugepage/enabled or whatever it says on your message. I had this error and that fixed that for me. That will add the line to your file, then restart.
I was just building my test ubuntu/redis base with telnet and got your error along the way too!
https://cloud.docker.com/u/coininstant/repository/docker/coininstant/redis

docker run -i -t coininstant/redis /bin/bash

to start server

/etc/init.d/redis-server start

redis-server

telnet 127.0.0.1 6379

ping (you'll get a pong in return)
quit (to quit telnet)

exit to exit root