Aug 2, 2018

Kafka Listeners - Explained

(This was cross-posted on the Confluent.io blog)

This question comes up on StackOverflow and such places a lot, so here’s something to try and help.

tl;dr : You need to set advertised.listeners (or KAFKA_ADVERTISED_LISTENERS if you’re using Docker images) to the external address (host/IP) so that clients can correctly connect to it. Otherwise they’ll try to connect to the internal host address–and if that’s not reachable then problems ensue.

Put another way, courtesy of Spencer Ruport:

LISTENERS are what interfaces Kafka binds to. ADVERTISED_LISTENERS are how clients can connect.

Install qemu on AWS EC2 Amazon Linux

Mucking about with virtual disks, I wanted to install qemu on a AWS EC2 instance in order to use qemu-img. Not finding it in a yum repo, I built it from scratch: $ uname -a Linux ip-10-0-1-238 4.4.41-36.55.amzn1.x86_64 #1 SMP Wed Jan 18 01:03:26 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux Steps: sudo yum install -y ghc-glib-devel ghc-glib autoconf autogen intltool libtool wget http://download.qemu-project.org/qemu-2.8.0.tar.xz tar xvJf qemu-2.8.0.tar.xz cd qemu-2.8.0 ./configure make sudo make install I hit a few errors, recorded here for passing Googlers: