Below you will find pages that utilize the taxonomy term “linux”
19. April 2018
Linux: query remote ntp (and show time difference)
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 188.8.131.52 s2 no-leap
7. December 2017
Howto: Disable persistent Network Interface Names (Debian Stretch)
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
8. September 2016
Quickly create a (swap)file on linux
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
31. August 2016
Migration of OpenVZ Container to KVM Guest
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.
19. August 2016
Moving to KVM
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.
16. June 2016
Running “backticks” commands on remote servers
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.
19. April 2016
Update for the Checklist on “mailout” servers
This is an update to the checklist to create a prefect mailout server: Original Checklist Setup DMARC DNS Record to receive mail delivery reports https://www.unlocktheinbox.com/dmarcwizard/ btw: I Just started adding all those settings to my own domain too. Google DKIM signing is still waiting for DNS propagation.
22. January 2016
Java SSL Certificate Verification Error
If you come across the situation, that your java programs are not able to connect to ssl encrypted services, it might be most likely that the java cacerts keystore is empty or not uptodate. This might also be due to a bug in the java (or ca-certificate-java) package ((https://bugs.launchpad.net/ubuntu/+source/ca-certificates-java/+bug/1396760)). In order to fix the issue, you can run: sudo /var/lib/dpkg/info/ca-certificates-java.postinst configure