Dropbear

Tag: Linux

  • Devices with cgroup v2

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    I was curious to find out how containers have restricted access to devices. For cgroup v1 this is simple, but cgroup v2 uses eBPF. Find out what device access a container has with 3 easy and 1 difficult steps.

  • Linux Memory Statistics

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    What does Used memory in Linux actually mean and how this concept has changed over the years.

  • Changing Grafana Legends

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    A quick tour of label_replace to fix Legend texts in Grafana for Prometheus data sources.

  • Percent CPU for processes

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    The ps program gives a snapshot of the processes running on your Unix-like system. On most Linux installations, this will be the ps program from the procps project. What does the %CPU field mean in the output of ps?

  • 25 Years of Free Software

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    When did I start writing Free Software, now called Open Source? That’s a tricky question. Does the time start with the first file edited, the first time it compiles or perhaps even some proto-program you use to work out a concept for the real program formed later on. So using the date you start writing,…

  • Sending data in a signal

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    The well-known kill system call has been around for decades and is used to send a signal to another process. The most common use is to terminate or kill another process by sending the KILL or TERM signal but it can be used for a form of IPC, usually around giving the other process a…

  • procps-ng 3.3.16

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    procps-ng version 3.3.16 was released today. Besides some documentation and library updates, there were a few incremental changes. Zombie Hunting with pgrep Ever wanted to find zombies? Perhaps processes with other states? pgrep has a shiny new runstate flag to help you which will match process against the runstate. I’m curious to see the use-cases…

  • psmisc 23.0

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    I had to go check but it has been over 3 years since the last psmisc release back in February 2014. I really didn’t think it had been that long ago.  Anyhow, with no further delay, psmisc version 23.0 has been released today! Update: 23.1 is out now, removed some debug line out of killall…

  • The sudo tty bug and procps

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    There have been recent reports of a security bug in sudo (CVE-2017-1000367) where you can fool sudo into thinking what controlling terminal it is running on to bypass its security checks.  One of the first things I thought of was, is procps vulnerable to the same bug? Sure, it wouldn’t be a security bypass, but…

  • Displaying Linux Memory

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    Memory management is hard, but RAM management may be even harder. Most people know the vague overall concept of how memory usage is displayed within Linux. You have your total memory which is everything inside the box; then there is used and free which is what the system is or is not using respectively. Some…