The Wiert Corner – irregular stream of stuff

Jeroen W. Pluimers on .NET, C#, Delphi, databases, and personal interests

  • My work

  • My badges

  • Twitter Updates

  • My Flickr Stream

    20140508-Delphi-2007--Project-Options--Cannot-Edit-Application-Title-HelpFile-Icon-Theming

    20140430-Fiddler-Filter-Actions-Button-Run-Filterset-now

    20140424-Windows-7-free-disk-space

    More Photos
  • Pages

  • All categories

  • Enter your email address to subscribe to this blog and receive notifications of new posts by email.

    Join 1,732 other followers

Archive for the ‘Power User’ Category

OpenSuSE Tumbleweed – when `halt` doesn’t halt, but CLI+HLT the CPU at the end of the shutdown procedure

Posted by jpluimers on 2017/04/26

When halt is not a real halt but a suspend of the CPU.

When halt is not a real halt but a “disabling” of the CPU.

TL;DR:

Don’t use halt, use poweroff instead.

A while ago I wrote about OpenSuSE 12.x not halting after a halt:

The same holds for more recent OpenSuSE systems, but ESXi would never tell what was going on.

Recently I installed an OpenSuSE Tumbleweed system under VMware Fusion (running on Mac OS X) which indicated “The CPU has been disabled by the guest operating system.”

Log indicates a

Log indicates a “Shutdown” which in fact is a CPU not powered down.

Which — Understanding the message: The CPU has been disabled by the guest operating system (2000542) | VMware KB [WayBack] — means that halt will not power down the VM but perform a CLI + HLT on the CPU. This effectively hangs the CPU even though the console log on the right tells does a real Shutdown.

In the past – even under ESXi – a halt would just power down the system, so based on the above I did more digging and fount this very interesting answer in rhel – What is the difference between these commands for bringing down a Linux server? – Unix & Linux Stack Exchange [WayBack] which comes down to:

  • on a systemd [WayBack] based system commands like halt, reboot, shutdown all invoke systemctl [WayBack] calling for a specific target [WayBack].
  • mapping of targets and commands is as follows (quoted from the answer):
    • systemctl isolate halt.target has the shorthands:
      • shutdown -H now
      • systemctl halt
      • plain unadorned halt
    • systemctl isolate reboot.target has the shorthands:
      • shutdown -r now
      • telinit 6
      • systemctl reboot
      • plain unadorned reboot
    • systemctl isolate poweroff.target has the shorthands:
      • shutdown -P now
      • telinit 0
      • shutdown now
      • systemctl poweroff
      • plain unadorned poweroff
    • systemctl isolate rescue.target has the shorthands:
      • telinit 1
      • systemctl rescue
    • systemctl isolate multi-user.target has the shorthands:
      • telinit 2
      • telinit 3
      • telinit 4
    • systemctl isolate graphical.target has the shorthand:
      • telinit 5

For a SysV [WayBack] init runlevels versus systemd targets see:

The systemd parameters making things a bit confusing, for instance you can do reboot --halt and more of those shown in linux – Are there any good reasons for halting system without cutting power? – Super User [WayBack].

That also explains that halt without a powerdown can be useful: it for instance gives the end-user the opportunity to click the reset button instead of the power button after a halt.

–jeroen

Posted in Power User, *nix, Linux, SuSE Linux, openSuSE, Tumbleweed, SysVinit, systemd | Leave a Comment »

Some links for MikroTik tips and scripts

Posted by jpluimers on 2017/04/25

MikroTik has great hardware, but getting things to work can be a bit ehm intimidating.

So here are some links that were useful getting my CCR1009 and CRS226 configurations to do what I wanted.

Very advanced stuff:

Packet flow (maybe the toughest part to wrap your head around):

Scripts:

Load balancing:

Syntax highlighting:

Pictures

Very well written blog:

Manito Network’s Mikrotik solutions blog. In-depth articles on Mikrotik routing, security, best practices, VPN, and more.

Source: Mikrotik — Manito Networks

Solutions for RouterOS-based Mikrotik networks. Includes security and best practices, VPN, routing, switching, and more.

Source: Mikrotik-1 — Manito Networks

–jeroen

Posted in Internet, IPSec, MikroTik, Network-and-equipment, OpenVPN, Power User, PPTP, Routers, VPN | Leave a Comment »

ANSI HTML Adapter example

Posted by jpluimers on 2017/04/24

ANSI HTML Adapter example installation on OpenSuSE Tumbleweed:

zypper addrepo http://download.opensuse.org/repositories/utilities/openSUSE_Factory/utilities.repo
zypper refresh
zypper install aha

On Mac OS X:

brew install aha

Output looks like this: ANSI HTML Adapter example:

diaspore:/etc # aha --version
Ansi Html Adapter Version 0.4.9.0
diaspore:/etc # aha --version | grep aha
diaspore:/etc # aha --version | aha

Ansi Html Adapter Version 0.4.9.0

And the aha --help output on Mac OS X:

Ansi Html Adapter Version 0.4.8.0
aha takes SGR-colored Input and prints W3C conform HTML-Code
use: aha <options> [-f file]
     aha (--help|-h|-?)
aha reads the Input from a file or stdin and writes HTML-Code to stdout
options: --black,      -b: Black Background and White "standard color"
         --pink,       -p: Pink Background
         --stylesheet, -s: Use a stylesheet instead of inline styles
         --iso X,    -i X: Uses ISO 8859-X instead of utf-8. X must be 1..16
         --title X,  -t X: Gives the html output the title "X" instead of
                           "stdin" or the filename
         --line-fix,   -l: Uses a fix for inputs using control sequences to
                           change the cursor position like htop. It's a hot fix,
                           it may not work with any program like htop. Example:
                           echo q | htop | aha -l > htop.htm
         --word-wrap,  -w: Wrap long lines in the html file. This works with
                           CSS3 supporting browsers as well as many older ones.
         --no-header,  -n: Don't include header into generated HTML,
                           useful for inclusion in full HTML files.
Example: aha --help | aha --black > aha-help.htm
         Writes this help text to the file aha-help.htm

Copyleft Alexander Matthes aka Ziz 2015
         zizsdl@googlemail.com
         http://ziz.delphigl.com/tool_aha.php
This application is subject to the MPL or LGPL.

–jeroen

Posted in *nix, Linux, openSuSE, Power User, SuSE Linux, Tumbleweed | Leave a Comment »

Some Wireshark links

Posted by jpluimers on 2017/04/24

I don’t use Wireshark enough to be fluent, so here are some links and quotes that proved to be useful for me:

–jeroen

Posted in *nix, *nix-tools, Power User, Wireshark | Leave a Comment »

opensuse – How to run my script after SuSE finished booting up? – Unix & Linux Stack Exchange

Posted by jpluimers on 2017/04/21

For future research: opensuse – How to run my script after SuSE finished booting up? – Unix & Linux Stack Exchange

Reason? Want to show the output of this as the last boot sequence line:

hostname
ip route
echo
ip address | grep -w 'UP\|flags\|inet\|inet6'
echo more detailed info through "ip address" and "ip route"
cat /etc/resolv.conf | grep nameserver

–jeroen

Posted in *nix, *nix-tools, bash, Linux, openSuSE, Power User, SuSE Linux, Tumbleweed | Leave a Comment »

 
%d bloggers like this: