SRE – Systems/Network

SRE – Systems and Network

Tips and tricks

  • It’s possible to easily generate a random file with specific size filled differently depending on the needs: Fill a 200MB file with zeroes dd if=/dev/zero of=/tmp/file.out bs=1024KB count=200 Fill a 200MB file with random values (longer than zeroes – depending…

  • You can get stuck with your ssh session when your network is changing or when there’s a network disruption. You will face a lock leading to the unability to stop your session, even by doing a CTRL-C. That’s why there’s…

  • Getting this error when trying to update packages on your linux distro using apt? $apt-get update W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://apt.puppetlabs.com…

  • It can be needed to test an UDP connection with a server to ensure that connectivity is working and double check the data received. Let’s take a simple example with a remote logstash server: – Server mylogstash.mydomain.local – Listening on…

  • Your monitoring system is claiming that your server is running out of free inodes but your disks are not full at all? Maybe you just need to check your filesystem usage and how many files are being used at the…

  • MySQL is an open-source relational database management system (RDBMS) available under the terms of the GNU General Public License, as well as under a variety of proprietary agreements. Thanks to some few functions, it’s possible to retrieve important information about…

  • With Linux version for Skype, it can happen that group conversation are not working as expected (conversations do not start, or updates are not working, or group members do not appear, …). You can check MSNP version you are using…

  • Once a docker container is started, it’s always hard to get access into and see what’s happening inside. As a workaround, the easiest way to understand what’s happening in a container is to get a CLI on it and investigate.…

  • You’re getting this annoying error message again and again when trying to fetch certificate and/or establish a connection to your website using openssl: 139647967614624:error:14077438:SSL routines:SSL23_GET_SERVER_HELLO:tlsv1 alert internal error:s23_clnt.c:769: This issue is well known in several openssl versions, and a bug…

  • If you want to isolate multiple networks, you can use VLAN (Virtual LAN). On most of the switches, you can configure VLAN to handle tagged packets and be able to send them to a specific port by isolating it. A…