Posts tagged "Linux"

7 articles

eBPF for Deep Observability Without Code Changes

May 23, 2023 333 words · 2 min read

Traditional observability requires instrumentation. Add libraries, modify code, redeploy. eBPF offers visibility into systems you can’t or won’t change, directly from the kernel. The Problem Instrumenting legacy applications was impractical. Some had no source code access. Others were …

Mounting raw disk images on Linux

Jan 12, 2021 311 words · 2 min read

From time to time you may have a raw disk image that you have made with the dd tool, or something similar. If it’s a backup of a single partition then it can be mounted in Linux using the loopback feature pretty easily, so long as you know the filesystem type, such as ext4, vfat or ntfs for …

Yum downgrade packages

Sep 5, 2016 720 words · 4 min read

If you upgrade RPMs with yum upgrade and then later wish you hadn’t done, then it is pretty simple to downgrade them using yum downgrade. Consider our example below, upgrading systemd: [vagrant@localhost ~]$ sudo yum upgrade systemd Loaded plugins: fastestmirror Loading mirror speeds from …

Finding number of connections from hosts using netstat

Jul 16, 2016 56 words · 1 min read

Perhaps you’re trying to find out where all your incoming connections are coming from to a server. If for example, it’s a MySQL database then you may be interested in connections on TCP port 3306. netstat -n | grep :3306 | awk '{ print $5 }' | cut -d':' -f1 | sort -n | …

Manually extending hard disk space

Jul 14, 2016 282 words · 2 min read

Perhaps an instance is running low on disk space and you’d like to extend it? Unfortunately on Skyscape there doesn’t seem to be a way to do this via terraform at present, but it can be achieved manually by: Skyscape Portal Login to the SkyScape’s portal Locate the vApp in …

Create a gem repo

Jan 31, 2015 2938 words · 14 min read

Creating your own gem repo is easy. Install ruby and rubygems packages Install the builder gem Run gem generate_index to create the repo metadata Publish the directory with indexing using your favourite web server In this example, we do the first 3 steps on Centos7 although the concept is the same …

Find all files larger than X on Linux

Mar 29, 2011 127 words · 1 min read

This example is for larger than 1GB… find /home -size +1000000k -exec du -sh {} \; if they are logs, you might want to truncate them… /usr/local/bin/trunc_our_app_logs.sh #!/bin/bash # NG20110329 - To trunc those pesky logs # ... trailing slashes are best as they work with symlinks …