How to stop AWS CLI clearing the screen

After a break from using AWS I had reason to reacquaint myself with it again today, and did so via the CLI. The AWS CLI is pretty intuitive and has a good helptext system, but one thing that kept frustrasting me was that after closing the help text, the screen cleared—so I couldn’t copy the syntax out to use in my command!

The same thing happened when I ran a command that returned output - the screen cleared.

Here’s how to fix either, or both, of these

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.

Mar 11, 2017

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:

Mar 11, 2017

Mount VMDK/OVF/OVA on Amazon Web Services (AWS) EC2

So you’ve got a Linux VM that you want to access the contents of in EC2 - how do you do it? Let’s see how. First up, convert the VMDK to raw image file. If you’ve got a ova/ovf then just untar it first (tar -xvf my_vm.ova), from which you should get the VMDK. With that, convert it using qemu-img: $ time qemu-img convert -f vmdk -O raw SampleAppv607p-appliance-disk1.vmdk SampleAppv607p-appliance-disk1.raw real 16m36.

Oct 14, 2016

boto / S3 errors

Presented without comment, warranty, or context - other than these might help a wandering code hacker. When using SigV4, you must specify a ‘host’ parameter boto.s3.connection.HostRequiredError: BotoClientError: When using SigV4, you must specify a 'host' parameter. To fix, switch conn_s3 = boto.connect_s3() for conn_s3 = boto.connect_s3(host='s3.amazonaws.com') You can see a list of endpoints here. boto.exception.S3ResponseError: S3ResponseError: 400 Bad Request Make sure you’re specifying the correct hostname (see above) for the bucket’s region.