Terminate the current EC2 instance /usr/bin/aws ec2 terminate-instances --instance-ids $(curl http://169.254.169.254/latest/meta-data/instance-id/) --region $(curl http://169.254.169.254/latest/dynamic/instance-identity/document | grep region | awk '{print $3}' | sed 's/"//g'|sed 's/,//g')

Sometimes you just want to query a remote ntp server (and maybe see the difference between the two clocks). In this case you can use the tool sntp. From the sntp man page: The default is to write the estimated correct local date and time (i.e. not UTC) to the standard output…. use something like: $ sntp at.pool.ntp.org 2018-04-19 11:36:26.538479 (-0100) -0.004752 +/- 0.023788 at.pool.ntp.org 86.59.28.10 s2 no-leap

I know I know, there are plenty of openssl cheat sheets out there already (1 or 2). But as I keep using googling it again and again to find the most useful openssl commands I decided to do my own – the first version of the blog entries is already 3 years old actually. Another reason for creating the list is that I remember things better when I am writing the down.

How to disable persistent network interface names in Debian 9 (Stretch) edit /etc/default/grub and change the following line GRUB_CMDLINE_LINUX="net.ifnames=0 biosdevname=0" afterwards run update-grub

Viewing a “raw” diff in Github is easy – if you know how. If you are viewing a commit on github the URL looks something like this: https://github.com/voxpupuli/puppet-php/commit/50e1c1733a931dd3d9d21db8a4f584c9984100d1 Adding “.diff” to the URL will generate the raw diff for you which you can pipe to patch etc. The full URL is: https://github.com/voxpupuli/puppet-php/commit/50e1c1733a931dd3d9d21db8a4f584c9984100d1.diff

The traditional way for creating a linux swapfile would be using dd to create an empty file e.g. dd if=/dev/zero of=/swapfile1 bs=1M count=2048 A faster way is to use “fallocate” e.g. (( http://www.cyberciti.biz/faq/ubuntu-linux-create-add-swap-file/ )) fallocate -l 2G /swapfile1 Don’t forget the usually procedure for swapfiles: chmod 0600 /swapfile1 chown root:root /swapfile1 mkswap /swapfile1 swapon /swapfile1 # edit /etc/fstab to add the swapfile during boot

This is a short tutorial how to migrate an OpenVZ container to a KVM Guest. Some ideas have been taken from other tutorials (1 and 2), the other half has been extracted from grml-debootstrap which can generate a KVM guest by using debootstrap. # form where to where migrate # don't forget the trailing / on the source! export SOURCE=/srv/vz/private/xxxxxxx/ # an empty LVM volume! export DEST=/dev/mapper/vg0-myfirstvm # create some magic for grub/partion table echo 4 66 | /usr/share/grml-debootstrap/bootgrub.

Since our beloved OpenVZ virutalisation technology is not moving in a direction we are comfortable with, we are currently evaluation several virtualisation technologies. One the the possible options is KVM. This is not a full tutorial about KVM, there are many good tutorials already, e.g. ((https://www.lisenet.com/2016/getting-started-with-kvm-on-debian-jessie/)) or ((http://linuxnewbieguide.org/?p=1993)) or ((http://xmodulo.com/use-kvm-command-line-debian-ubuntu.html)) or ((http://wiki.libvirt.org/page/UbuntuKVMWalkthrough)) or ((http://www.cyberciti.biz/faq/how-to-install-kvm-on-ubuntu-linux-14-04/)), this is just a collection of some notes which I collected during the evaluation. General Documentation RedHat has some good KVM virtualisation documentation available at: https://access.

Sometimes it’s necessary to run a complex command on a remote server witch also includes some “backticks”. Usually these commands are interpreted by the local shell so you need to use a little trick to force execution on the remote server: ssh this.is.my.beautiful.server '( echo `echo "This Command is run on the remote server" ` )' You need to use single quotes combined with brackets to use the backtick on the remote server.