Firejail: Putting a program in its own little container

Introduction Firejail is a lightweight security utility which ties the hands of running processes, somewhat like Apparmor and SELinux. However it takes the mission towards Linux kernel’s cgroups and namespaces. It’s in fact a bit of a container-style virtualization utility, which creates sandboxes for running specific programs: Instead of a container for an entire operating [...]

MySQL, OOM killer, overcommitting and other memory related issues

It started with an error message This post is a bit of a coredump of myself attempting to resolve a sudden web server failure. And even more important, understand why it happened (check on that) and try avoiding it from happening in the future (not as lucky there). I’ve noticed that there are many threads [...]

Upgrading to Linux Mint 19, running the old system in a chroot

Background Archaeological findings have revealed that prehistoric humans buried their forefathers under the floor of their huts. Fast forward to 2018, yours truly decided to continue running the (ancient) Fedora 12 as a chroot when migrating to Linux Mint 19. That’s an eight years difference. While a lot of Linux users are happy to just [...]

VMplayer: Silencing excessive hard disk activity + getting rid of freezes

The disk is hammering For some unknown reason, possibly after an VMplayer upgrade, running any Windows Virtual machine on my Linux machine with WMware Player caused some non-stop heavy hard disk activity, even when the guest machine was effectively idle, and made had no I/O activity of its own. Except for being surprisingly annoying, it [...]

Playing with Linux namespaces

Intro Linux namespaces is the foundation for container-based virtualization, which is becoming increasingly popular. Aside from the ability to isolate a shell (and the processes it generates) from the “main environment”, as is required for this kind of lightweight virtualization, namespaces is useful for overriding selected functionalities. So I’m jotting down things I use myself. [...]

VMware Player or Workstation: Patching for Linux kernel 3.12 (or so)

For a reason not so clear to me, VMware doesn’t keep its drivers up to date with newer kernels, so they fail to compile against newer kernels. Consequently, there’s an insane race to patch them up. It starts with a compilation failure at the GUI level, and sooner or later it becomes clear that there’s [...]

Running a nested X-Windows server

Why? It’s sometimes desired to run an X-Windows program in a separate “screen” but not actually have another screen. The expensive way is to bring up a whole virtual server. But if it’s fine to run the program on the same computer, all we want is to have a window, in which the program is [...]

Setting up a VPS server. It was a bumpy road.

Introduction These are my own notes as I set up an OpenVZ VPS server, based upon CentOS 5.6 to function as a web and mailing list server. A $36/year 128 MB RAM machine was good enough for this. Since there’s some criticism about the hosting provider, and it looks like they’re OK after all, I’m [...]

Virtualization: Notes to self

This is just things I wrote down while playing with QEMU/KVM virtualization, for my own purposes of packing two existing computers into a third one. There is no point to make here, and neither do I expect anyone to understand this. It’s published because I don’t care to. Log files There are definitely two files [...]

Installing .so libraries on a 64-bit Fedora with yum

A short note about installing libraries on an Intel 64 bit machine (Fedora 12 in my case). It all starts with a short conversation like this one: [root@short Downloads]# rpm -i VirtualBox-3.1-3.1.2_56127_fedora12-1.x86_64.rpm error: Failed dependencies: is needed by VirtualBox-3.1-3.1.2_56127_fedora12-1.x86_64 is needed by VirtualBox-3.1-3.1.2_56127_fedora12-1.x86_64 THE WRONG THING TO DO IS: [root@short Downloads]# [...]