Posts Tagged ‘need’

OpenVZ enable or disable auto start on Linux Hypervisor host boot for Virtual Machine containers

Wednesday, July 7th, 2021

howto-add-virtual-machine-to-auto-start-with-vz-openvz-linux-containers-4-logo-slogan-vertical-big

To make OpenVZ / Virtuozzo Hypervisor servers and you are not sure whether your configured container virtual machines are configured to automatically boot on Linux Physical OS host boot in case of restart after patch update set or after unexpected shutdown due to Kernel / OS bug a hang or due to some electricity Power outage.

To check what is your current configuration for Virtual Environment on CentOS Linux you need to check inside /etc/sysconfig/vz-scripts/VEID.conf
You need to check the value for inside the file

ONBOOT="" 

To get the exact ID of "VEID.conf of the current openvz guest VM containers exec:

[root@openvz vz-scripts]# vzlist -a
      CTID      NPROC STATUS    IP_ADDR         HOSTNAME
       300         23 running   10.10.10.1     VirtualMachine1
       301         25 running   10.10.10.2     VirtualMachine2

[root@openvz ~]# cd /etc/sysconfig/vz-scripts
[root@gbapp2 vz-scripts]# pwd
/etc/sysconfig/vz-scripts

[root@openvz vz-scripts]# grep -i ONBOOT 300.conf 301.conf
300.conf:ONBOOT="yes"
301.conf:ONBOOT="yes"

If you happen to have configured ONBOOT="no" you will need to the change to respective VEID.conf:

vi /etc/sysconfig/vz-scripts/VEID.conf

search for

ONBOOT=”no”

and change to

ONBOOT=”yes”

OpenVZ_virtuozzo-standard-process-tree-landscape

OpenVZ server process tree. The colors of the virtual severs are indicated by colors.

OpenVZ Quick cheat sheet commands

This change will auto-start the VPS container next time the host Hypervisor node is rebooted.
If you happen to have daily work with OpenVZ legacy systems like I do you might find also useful the following OpenVZ Cheatsheet pdf document.

A miniature quick cheatsheet for OpenVZ Virtualion, in case if you are like me and you have to use various virtualization technologies and tend to forget is as below:

vzlist                               # List running instances
vzlist -a                            # List all instances

 

vzctl stop <instance>
vzctl start <instance>
vzctl status <instance>

vzctl exec <instance> <command>      # Run a command

vzctl enter <instance>               # Get console

vzyum <instance> install <package>   # Install a package


# Change properties
vzctl set <instance> –hostname <hostname> –save
vzctl set <instance> –ipadd <IP> –save
vzctl set <instance> –userpasswd root:<password> –save

If need to get more insight on how OpenVZ Virtualization does work on a low level and stretch out its possibilities, an old but useful document you might want to check is OpenVZ-Users-Guide PDF.


If you need it to hava e copy of it openvz_cheat_sheet.txt.

KVM Virtual Machine RHEL 8.3 Linux install on Redhat 8.3 Linux Hypervisor with custom tailored kickstart.cfg

Friday, January 22nd, 2021

kvm_virtualization-logo-redhat-8.3-install-howto-with-kickstart

If you don't have tried it yet Redhat and CentOS and other RPM based Linux operationg systems that use anaconda installer is generating a kickstart file after being installed under /root/{anaconda-ks.cfg,initial-setup- ks.cfg,original-ks.cfg} immediately after the OS installation completes. Using this Kickstart file template you can automate installation of Redhat installation with exactly the same configuration as many times as you like by directly loading your /root/original-ks.cfg file in RHEL installer.

Here is the official description of Kickstart files from Redhat:

"The Red Hat Enterprise Linux installation process automatically writes a Kickstart file that contains the settings for the installed system. This file is always saved as /root/anaconda-ks.cfg. You may use this file to repeat the installation with identical settings, or modify copies to specify settings for other systems."


Kickstart files contain answers to all questions normally asked by the text / graphical installation program, such as what time zone you want the system to use, how the drives should be partitioned, or which packages should be installed. Providing a prepared Kickstart file when the installation begins therefore allows you to perform the installation automatically, without need for any intervention from the user. This is especially useful when deploying Redhat based distro (RHEL / CentOS / Fedora …) on a large number of systems at once and in general pretty useful if you're into the field of so called "DevOps" system administration and you need to provision a certain set of OS to a multitude of physical servers or create or recreate easily virtual machines with a certain set of configuration.
 

1. Create /vmprivate storage directory where Virtual machines will reside

First step on the Hypervisor host which will hold the future created virtual machines is to create location where it will be created:

[root@redhat ~]#  lvcreate –size 140G –name vmprivate vg00
[root@redhat ~]#  mkfs.ext4 -j -b 4096 /dev/mapper/vg00-vmprivate
[root@redhat ~]# mount /dev/mapper/vg00-vmprivate /vmprivate

To view what is the situation with Logical Volumes and  VG group names:

[root@redhat ~]# vgdisplay -v|grep -i vmprivate -A7 -B7
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  – currently set to     8192
  Block device           253:0

 

  — Logical volume —
  LV Path                /dev/vg00/vmprivate
  LV Name                vmprivate
  VG Name                vg00
  LV UUID                VVUgsf-FXq2-TsMJ-QPLw-7lGb-Dq5m-3J9XJJ
  LV Write Access        read/write
  LV Creation host, time lpgblu01f.ffm.de.int.atosorigin.com, 2021-01-20 17:26:11 +0100
  LV Status              available
  # open                 1
  LV Size                150.00 GiB


Note that you'll need to have the size physically available on a SAS / SSD Hard Drive physically connected to Hypervisor Host.

To make the changes Virtual Machines storage location directory permanently mounted add to /etc/fstab

/dev/mapper/vg00-vmprivate  /vmprivate              ext4    defaults,nodev,nosuid 1 2

[root@redhat ~]# echo '/dev/mapper/vg00-vmprivate  /vmprivate              ext4    defaults,nodev,nosuid 1 2' >> /etc/fstab

 

2. Second we need to install the following set of RPM packages on the Hypervisor Hardware host

[root@redhat ~]# yum install qemu-kvm qemu-img libvirt virt-install libvirt-client virt-manager libguestfs-tools virt-install virt-top -y

3. Enable libvirtd on the host

[root@redhat ~]#  lsmod | grep -i kvm
[root@redhat ~]#  systemctl enable libvirtd

4. Configure network bridging br0 interface on Hypervisor


In /etc/sysconfig/network-scripts/ifcfg-eth0 you need to include:

NM_CONTROLED=NO

Next use nmcli redhat configurator to create the bridge (you can use ip command instead) but since the tool is the redhat way to do it lets do it their way ..

[root@redhat ~]# nmcli connection delete eno3
[root@redhat ~]# nmcli connection add type bridge autoconnect yes con-name br0 ifname br0
[root@redhat ~]# nmcli connection modify br0 ipv4.addresses 10.80.51.16/26 ipv4.method manual
[root@redhat ~]# nmcli connection modify br0 ipv4.gateway 10.80.51.1
[root@redhat ~]# nmcli connection modify br0 ipv4.dns 172.20.88.2
[root@redhat ~]# nmcli connection add type bridge-slave autoconnect yes con-name eno3 ifname eno3 master br0
[root@redhat ~]# nmcli connection up br0

5. Prepare a working kickstart.cfg file for VM


Below is a sample kickstart file I've used to build a working fully functional Virtual Machine with Red Hat Enterprise Linux 8.3 (Ootpa) .

#version=RHEL8
#install
# Run the Setup Agent on first boot
firstboot --enable
ignoredisk --only-use=vda

# Use network installation
#url --url=http://hostname.com/rhel/8/BaseOS
##url --url=http://171.23.8.65/rhel/8/os/BaseOS

# Use text mode install
text
#graphical

# System language
#lang en_US.UTF-8
keyboard --vckeymap=us --xlayouts='us'
# Keyboard layouts
##keyboard us
lang en_US.UTF-8

# Root password
rootpw $6$gTiUCif4$YdKxeewgwYCLS4uRc/XOeKSitvDJNHFycxWVHi.RYGkgKctTMCAiY2TErua5Yh7flw2lUijooOClQQhlbstZ81 --iscrypted

# network-stuff
# place ip=your_VM_IP, netmask, gateway, nameserver hostname 
network --bootproto=static --ip=10.80.21.19 --netmask=255.255.255.192 --gateway=10.80.21.1 --nameserver=172.30.85.2 --device=eth0 --noipv6 --hostname=FQDN.VMhost.com --onboot=yes
# if you need just localhost initially configured uncomment and comment above
##network В --device=lo --hostname=localhost.localdomain

# System authorization information
authconfig --enableshadow --passalgo=sha512 --enablefingerprint

# skipx
skipx

# Firewall configuration
firewall --disabled

# System timezone
timezone Europe/Berlin

# Clear the Master Boot Record
##zerombr

# Repositories
## Add RPM repositories from KS file if necessery
#repo --name=appstream --baseurl=http://hostname.com/rhel/8/AppStream
#repo --name=baseos --baseurl=http://hostname.com/rhel/8/BaseOS
#repo --name=inst.stage2 --baseurl=http://hostname.com ff=/dev/vg0/vmprivate
##repo --name=rhsm-baseos В  В --baseurl=http://172.54.8.65/rhel/8/rhsm/x86_64/BaseOS/
##repo --name=rhsm-appstream --baseurl=http://172.54.8.65/rhel/8/rhsm/x86_64/AppStream/
##repo --name=os-baseos В  В  В --baseurl=http://172.54.9.65/rhel/8/os/BaseOS/
##repo --name=os-appstream В  --baseurl=http://172.54.8.65/rhel/8/os/AppStream/
#repo --name=inst.stage2 --baseurl=http://172.54.8.65/rhel/8/BaseOS

# Disk partitioning information set proper disk sizing
##bootloader --location=mbr --boot-drive=vda
bootloader --append=" crashkernel=auto tsc=reliable divider=10 plymouth.enable=0 console=ttyS0 " --location=mbr --boot-drive=vda
# partition plan
zerombr
clearpart --all --drives=vda --initlabel
part /boot --size=1024 --fstype=ext4 --asprimary
part swap --size=1024
part pv.01 --size=30000 --grow --ondisk=vda
##part pv.0 --size=80000 --fstype=lvmpv
#part pv.0 --size=61440 --fstype=lvmpv
volgroup s pv.01
logvol / --vgname=s --size=15360 --name=root --fstype=ext4
logvol /var/cache/ --vgname=s --size=5120 --name=cache --fstype=ext4 --fsoptions="defaults,nodev,nosuid"
logvol /var/log --vgname=s --size=7680 --name=log --fstype=ext4 --fsoptions="defaults,nodev,noexec,nosuid"
logvol /tmp --vgname=s --size=5120 --name=tmp --fstype=ext4 --fsoptions="defaults,nodev,nosuid"
logvol /home --vgname=s --size=5120 --name=home --fstype=ext4 --fsoptions="defaults,nodev,nosuid"
logvol /opt --vgname=s --size=2048 --name=opt --fstype=ext4 --fsoptions="defaults,nodev,nosuid"
logvol /var/log/audit --vgname=s --size=3072 --name=audit --fstype=ext4 --fsoptions="defaults,nodev,nosuid"
logvol /var/spool --vgname=s --size=2048 --name=spool --fstype=ext4 --fsoptions="defaults,nodev,nosuid"
logvol /var --vgname=s --size=7680 --name=var --fstype=ext4 --fsoptions="defaults,nodev,nosuid"

# SELinux configuration
selinux --disabled
# Installation logging level
logging --level=debug

# reboot automatically
reboot

###

%packages
@standard
python3
pam_ssh_agent_auth
-nmap-ncat
#-plymouth
#-bpftool
-cockpit
#-cryptsetup
-usbutils
#-kmod-kvdo
#-ledmon
#-libstoragemgmt
#-lvm2
#-mdadm
-rsync
#-smartmontools
-sos
-subscription-manager-cockpit
# Tune Linux vm.dirty_background_bytes (IMAGE-439)
# The following tuning causes dirty data to begin to be background flushed at
# 100 Mbytes, so that it writes earlier and more often to avoid a large build
# up and improving overall throughput.
echo "vm.dirty_background_bytes=100000000" >> /etc/sysctl.conf

# Disable kdump
systemctl disable kdump.service
%end

Important note to make here is the MD5 set root password string in (rootpw) line this string can be generated with openssl or mkpasswd commands :

Method 1: use openssl cmd to generate (md5, sha256, sha512) encrypted pass string

[root@redhat ~]# openssl passwd -6 -salt xyz test
$6$xyz$rjarwc/BNZWcH6B31aAXWo1942.i7rCX5AT/oxALL5gCznYVGKh6nycQVZiHDVbnbu0BsQyPfBgqYveKcCgOE0

Note: passing -1 will generate an MD5 password, -5 a SHA256 encryption and -6 SHA512 encrypted string (logically recommended for better security)

Method 2: (md5, sha256, sha512)

[root@redhat ~]# mkpasswd –method=SHA-512 –stdin

The option –method accepts md5, sha-256 and sha-512
Theoretically there is also a kickstart file generator web interface on Redhat's site here however I never used it myself but instead use above kickstart.cfg
 

6. Install the new VM with virt-install cmd


Roll the new preconfigured VM based on above ks template file use some kind of one liner command line  like below:
 

[root@redhat ~]# virt-install -n RHEL8_3-VirtualMachine –description "CentOS 8.3 Virtual Machine" –os-type=Linux –os-variant=rhel8.3 –ram=8192 –vcpus=8 –location=/vmprivate/rhel-server-8.3-x86_64-dvd.iso –disk path=/vmprivate/RHEL8_3-VirtualMachine.img,bus=virtio,size=70 –graphics none –initrd-inject=/root/kickstart.cfg –extra-args "console=ttyS0 ks=file:/kickstart.cfg"

7. Use a tiny shell script to automate VM creation


For some clarity and better automation in case you plan to repeat VM creation you can prepare a tiny bash shell script:
 

#!/bin/sh
KS_FILE='kickstart.cfg';
VM_NAME='RHEL8_3-VirtualMachine';
VM_DESCR='CentOS 8.3 Virtual Machine';
RAM='8192';
CPUS='8';
# size is in Gigabytes
VM_IMG_SIZE='140';
ISO_LOCATION='/vmprivate/rhel-server-8.3-x86_64-dvd.iso';
VM_IMG_FILE_LOC='/vmprivate/RHEL8_3-VirtualMachine.img';

virt-install -n "$VMNAME" –description "$VM_DESCR" –os-type=Linux –os-variant=rhel8.3 –ram=8192 –vcpus=8 –location="$ISO_LOCATION" –disk path=$VM_IMG_FILE,bus=virtio,size=$IMG_VM_SIZE –graphics none –initrd-inject=/root/$KS_FILE –extra-args "console=ttyS0 ks=file:/$KS_FILE"


A copy of virt-install.sh script can be downloaded here

Wait for the installation to finish it should be visualized and if all installation is smooth you should get a login prompt use the password generated with openssl tool and test to login, then disconnect from the machine by pressing CTRL + ] and try to login via TTY with

[root@redhat ~]# virst list –all
 Id   Name        State
—————————
 2    
RHEL8_3-VirtualMachine   running

[root@redhat ~]#  virsh console RHEL8_3-VirtualMachine


redhat8-login-prompt

One last thing I recommend you check the official documentation on Kickstart2 from CentOS official website

In case if you later need to destroy the VM and the respective created Image file you can do it with:
 

[root@redhat ~]#  virsh destroy RHEL8_3-VirtualMachine
[root@redhat ~]#  virsh undefine RHEL8_3-VirtualMachine

Don't forget to celebreate the success and give this nice article a credit by sharing this nice tutorial with a friend or by placing a link to it from your blog 🙂

 

 

Enjoy !

Configure rsyslog buffering on Linux to avoid message lost to Central Logging server

Wednesday, January 13th, 2021

rsyslog-Centralized-Logging-System-using-Rsyslog_logo

1. Rsyslog Buffering

One of the best practice about logs management is to send syslog to a central server. However, a logging system should be capable of avoiding message loss in situations where the server is not reachable. To do so, unsent data needs to be buffered at the client when central server is not available. You might have recently noticed that many servers forwarding logs messages to a central server do not have buffering functionalities activated. Thus I strongly advise you to have look to this documentation to know how to check your configuration: http://www.rsyslog.com/doc/rsyslog_reliable_forwarding.html

Rsyslog buffering with TCP/UDP configured

In rsyslog, every action runs on its own queue and each queue can be set to buffer data if the action is not ready. Of course, you must be able to detect that "the action is not ready", which means the remote server is offline. This can be detected with plain TCP syslog and RELP, but not with UDP. So you need to use either of the two. In this howto, we use plain TCP syslog.

– Version requirement

Please note that we are using rsyslog-specific features. The are required on the client, but not on the server. So the client system must run rsyslog (at least version 3.12.0), while on the server another syslogd may be running, as long as it supports plain tcp syslog.

How To Setup rsyslog buffering on Linux

First, you need to create a working directory for rsyslog. This is where it stores its queue files (should need arise). You may use any location on your local system. Next, you need to do is instruct rsyslog to use a disk queue and then configure your action. There is nothing else to do. With the following simple config file, you forward anything you receive to a remote server and have buffering applied automatically when it goes down. This must be done on the client machine.

# Example:
# $ModLoad imuxsock             # local message reception
# $WorkDirectory /rsyslog/work  # default location for work (spool) files
# $ActionQueueType LinkedList   # use asynchronous processing
# $ActionQueueFileName srvrfwd  # set file name, also enables disk mode
# $ActionResumeRetryCount -1    # infinite retries on insert failure
# $ActionQueueSaveOnShutdown on # save in-memory data if rsyslog shuts down
# *.*       @@server:port

Howto create Linux Music Audio CD from MP3 files / Create playable WAV format Audio CD Albums from MP3s

Tuesday, July 16th, 2019

cdburning-audio-music-cd-from-mp3-on-linuxcomapct-disc-tux-linux-logo

Recently my Mother asked me to prepare a Music Audio CD for her from a popular musician accordionist Stefan Georgiev from Dobrudja who has a unique folklore Bulgarian music.

As some of older people who still remember the age of the CD and who had most likely been into the CD burning Copy / Piracy business so popular in the countries of the ex-USSR so popular in the years 1995-2000 audio ,  Old CD Player Devices were not able to play the MP3 file format due to missing codecs (as MP3 was a proprietary compression that can't be installed on every device without paying the patent to the MP3 compression rights holder.

The revolutionary MP3 compression used to be booming standard for transferring Music data due to its high compression which made an ordinary MP3 of 5 minutes of 5MB (10+ times more compression than an ordinary classic WAV Audio the CPU intensiveness of MP3 files that puts on the reading device, requiring the CD Player to have a more powerful CPU.

Hence  due to high licensing cost and requirement for more powerful CPU enabled Audio Player many procuders of Audio Players never introduced MP3 to their devices and MP3 Neve become a standard for the Audio CD that was the standard for music listening inside almost every car out there.

Nowdays it is very rare need to create a Audio CD as audio CDs seems to be almost dead (As I heard from a Richard Stallman lecture In USA nowadays there is only 1 shop in the country where you can still buy CD or DVD drives) and only in third world as Africa Audio CDs perhaps are still in circulation.

Nomatter that as we have an old Stereo CD player on my village and perhaps many others, still have some old retired CD reading devices being able to burn out a CD is a useful thing.

Thus to make mother happy and as a learning excercise, I decided to prepare the CD for her on my Linux notebook.
Here I'll shortly describe the takes I took to make it happen which hopefully will be useful for other people that need to Convert and burn Audio CD from MP3 Album.

 

1. First I downloaded the Album in Mp3 format from Torrent tracker

My homeland Bulgaria and specific birth place place the city of Dobrich has been famous its folklore:  Galina Durmushlijska and Stefan Georgiev are just 2 of the many names along with Оркестър Кристал (Orchestra Crystal) and the multitude of gifted singers. My mother has a santiment for Stefan Georgiev, as she listened to this gifted accordinist on her Uncle's marriage.

Thus In my case this was (Стефан Георгиев Хора и ръченици от Добруджа) the album full song list here If you're interested to listen the Album and Enjoy unique Folklore from Dobrudja (Dobrich) my home city, Stefan Georgiev's album Hora and Rachenica Dances is available here

 


Stefan_Georgiev-old-audio-Music-CD-Hora-i-Rychenici-ot-Dobrudja-Horos-and-Ruchenitsas-from-Dobrudja-CD_Cover
I've downloaded them from Bulgarian famous torrent tracker zamunda.net in MP3 format.
Of course you need to have a CD / DVD readed and write device on the PC which nowdays is not present on most modern notebooks and PCs but as a last resort you can buy some cheap External Optical CD / DVD drive for 25 to 30$ from Amazon / Ebay etc.

 

2. You will need to install a couple of programs on Linux host (if you don't have it already)


To be able to convert from command line from MP3 to WAV you will need as minimum ffmpeg and normalize-audio packages as well as some kind of command line burning tool like cdrskin  wodim which is
the fork of old good known cdrecord, so in case if you you're wondering what happened with it just
use instead wodim.

Below is a good list of tools (assuming you have enough HDD space) to install:

 

root@jeremiah:/ # apt-get install –yes dvd+rw-tools cdw cdrdao audiotools growisofs cdlabelgen dvd+rw-tools k3b brasero wodim ffmpeg lame normalize-audio libavcodec58

 

Note that some of above packages I've installed just for other Write / Read operations for DVD drives and you might not need that but it is good to have it as some day in future you will perhaps need to write out a DVD or something.
Also the k3b here is specific to KDE and if you're a GNOME user you could use Native GNOME Desktop app such brasero or if you're in a more minimalistic Linux desktop due to hardware contrains use XFCE's native xfburn program.

If you're a console / terminal geek like me you will definitely enjoy to use cdw
 

root@jeremiah:/ # apt-cache show cdw|grep -i description -A 1
Description-en: Tool for burning CD's – console version
 Ncurses-based frontend for wodim and genisoimage. It can handle audio and

Description-md5: 77dacb1e6c00dada63762b78b9a605d5
Homepage: http://cdw.sourceforge.net/

 

3. Selecting preferred CD / DVD / BD program to use to write out the CD from Linux console


cdw uses wodim (which is a successor of good old known console cdrecord command most of use used on Linux in the past to burn out new Redhat / Debian / different Linux OS distro versions for upgrade purposes on Desktop and Server machines.

To check whether your CD / DVD drive is detected and ready to burn on your old PC issue:

 

root@jeremiah:/# wodim -checkdrive
Device was not specified. Trying to find an appropriate drive…
Detected CD-R drive: /dev/cdrw
Using /dev/cdrom of unknown capabilities
Device type    : Removable CD-ROM
Version        : 5
Response Format: 2
Capabilities   :
Vendor_info    : 'HL-DT-ST'
Identification : 'DVDRAM GT50N    '
Revision       : 'LT20'
Device seems to be: Generic mmc2 DVD-R/DVD-RW.
Using generic SCSI-3/mmc   CD-R/CD-RW driver (mmc_cdr).
Driver flags   : MMC-3 SWABAUDIO BURNFREE
Supported modes: TAO PACKET SAO SAO/R96P SAO/R96R RAW/R16 RAW/R96P RAW/R96R

You can also use xorriso (whose added value compared to other console burn cd tools is is not using external program for ISO9660 formatting neither it use an external or an external burn program for CD, DVD or BD (Blue Ray) drive but it has its own libraries incorporated from libburnia-project.org libs.

Below output is from my Thinkpad T420 notebook. If the old computer CD drive is there and still functional in most cases you should not get issues to detect it.

cdw ncurses text based CD burner tool's interface is super intuitive as you can see from below screenshot:

cdw-burn-cds-from-console-terminal-on-GNU-Linux-and-FreeBSD-old-PC-computer

CDW has many advanced abilities such as “blanking” a disk or ripping an audio CD on a selected folder. To overcome the possible problem of CDW not automatically detecting the disk you have inserted you can go to the “Configuration” menu, press F5 to enter the Hardware options and then on the first entry press enter and choose your device (by pressing enter again). Save the setting with F9.
 

4. Convert MP3 / MP4 Files or whatever format to .WAV to be ready to burn to CD


Collect all the files you want to have collected from the CD album in .MP3 a certain directory and use a small one liner loop to convert files to WAV with ffmpeg:
 

cd /disk/Music/Mp3s/Singer-Album-directory-with-MP3/

for i in $( ls *.mp3); do ffmpeg -i $i $i.wav; done


If you don't have ffmpeg installed and have mpg123 you can also do the Mp3 to WAV conversion with mpg123 cmd like so:

 

for i in $( ls ); do mpg123 -w $i.wav $i.mp3; done


Another alternative for conversion is to use good old lame (used to create Mp3 audio files but abling to also) decode
mp3 to wav.

 

lame –decode somefile.mp3 somefile.wav


In the past there was a burn command tool that was able to easily convert MP3s to WAV but in up2date Linux modern releases it is no longer available most likely due to licensing issues, for those on older Debian Linux 7 / 8 / 9 / Ubuntu 8 to 12.XX / old Fedoras etc. if you have the command you can install burn and use it (and not bother with shell loops):

apt-get install burn

or

yum install burn


Once you have it to convert

 

$ burn -A -a *.mp3
 

 

5. Fix file naming to remove empty spaces such as " " and substitute to underscores as some Old CD Players are
unable to understand spaces in file naming with another short loop.

 

for f in *; do mv "$f" `echo $f | tr ' ' '_'`; done

 

6. Normalize audio produced .WAV files (set the music volume to a certain level)


In case if wondering why normalize audio is needed here is short extract from normalize-audio man page command description to shed some light.

"normalize-audio  is  used  to  adjust  the volume of WAV or MP3 audio files to a standard volume level.  This is useful for things like creating mp3 mixes, where different recording levels on different albums can cause the volume to  vary  greatly from song to song."
 

cd /disk/Music/Mp3s/Singer-Album-directory-with-MP3/

normalize-audio -m *.wav

 

7. Burn the produced normalized Audio WAV files to the the CD

 

wodim -v -fix -eject dev='/dev/sr0' -audio -pad *.wav


Alternatively you can conver all your MP3 files to .WAV with anything be it audacity
or another program or even use 
GNOME's CDBurn tool brasero (if gnome user) or KDE's CDBurn which in my opinion is
the best CD / DVD burning application for Linux K3B.

Burning Audio CD with K3b is up to few clicks and super easy and even k3b is going to handle the MP3 to WAV file Conversion itself. To burn audio with K3B just run it and click over 'New Audio CD Project'.

k3b-on-debian-gnu-linux-burn-audio-cd-screenshot

For those who want to learn a bit more on CD / DVD / Blue-Ray burning on GNU / Linux good readings are:
Linux CD Burning Mini Howto, is Linux's CD Writing Howto on ibiblio (though a bit obsolete) or Debian's official documentation on BurnCD.
 

8. What we learned here


Though the accent of this tutorial was how to Create Audio Music CD from MP3 on GNU / Linux, the same commands are available in most FreeBSD / NetBSD / OpenBSD ports tree so you can use the same method to build prepare Audio Music CD on *BSDs.

In this article, we went through few basic ways on how to prepare WAV files from MP3 normalize the new created WAV files on Linux, to prepare files for creation of Audio Music CD for the old mom or grandma's player or even just for fun to rewind some memories. For GUI users this is easily done with  k3b,  brasero or xfburn.

I've pointed you to cdw a super useful text ncurses tool that makes CD Burninng from plain text console (on servers) without a Xorg / WayLand  GUI installed super easy. It was shortly reviewed what has changed over the last few years and why and why cdrecord was substituted for wodim. A few examples were given on how to handle conversion through bash shell loops and you were pointed to some extra reading resources to learn a bit more on the topic.
There are plenty of custom scripts around for doing the same CD Burn / Covnersion tasks, so pointing me to any external / Shell / Perl scripts is mostly welcome.

Hope this learned you something new, Enjoy ! 🙂

How to synchronize with / from Remote FTP server using LFTP like with rsync

Sunday, October 15th, 2017

how-to-synchronize-from-remote-ftp-server-easily-like-rsync.jpg

Have you ever been in a need to easily synchronize with a remote host which only runs FTP server?

Or are you in a local network and you need to mirror a directory or a couple of directories in a fast and easy to remember way?

If so then you'll be happy to use below LFTP command that is doing pretty much the same as Rsync, with only difference that it can mirror files over FTP (old but gold File Transfer Protocol).
 

lftp -u FTP_USERNAME,FTP_PASSWORD -e 'mirror REMOTE_DIRECTORY LOCAL_DIRECTORY' FTP_SERVER_HOSTNAME


Enjoy and thanks to my dear friend Amridikon for the tip ! 🙂

How to Increase virtualbox Linux install machine VM .VDI hard disk size to free space on root partition – Move /usr to a new partition

Tuesday, October 10th, 2017

extend-vdi-virtual-machine-partition-with-virtualbox-howto-virtualbox-logo
 

How to Increse Hard Disk size of VirtualBox Virtual Machine .VDI file to Free Space on root Partition or Howto move /usr large partition to separate new partition?


I just wondered how to increase hard disk size of Virtualbox Virtual Machine image .VDI, because for some stupid reason I've created my initial hard disk size for Linux partition to be the default 10 Gigabytes.

The problem is the packages I need to have installed on the Virtual Machine which will be a testbed for future tests of a production website applications are taking up too much space, once installed so I'm left with no space
in /var/lib/mysql for the database import. So what can I do in that case is to simply free up disk space or Merge ROOT partition with another partition.

Since merging the partition is not a trivial job and would require me to have installable CD with the Linux distro (in my case that's Debian Linux) or have a bootable USB flash drive, I preferred second approach to problem e.g. to free up disk space on ROOT partition by creating a second partition and move the /usr folder to reside there.

Before that it is of course necessery to  have extended the .VDI file using VirtualBox, so more space than the default 10GB preconfigured are available, this is easily done on Windows OS as, VBox is provided with GUI clickable option to do it, but for who knows what reason that is not the case with Linux, so Linux users only option to increase VDI file is to manually run command part of the virtualbox package, that is not a hard task really but it requires some typing and basic knowledge on how to run commands in terminal.


To .VDI resize (extend), we first go to default location where VirtualBox stores its image .VDI files (by default as of moment of writting this article – this is ~/"VrtualBox VMs"  (or home directory of logged in user dir VirtualBox VMs), the command to use is VBoxManage

 

root@jericho:/home/hipo# cd VirtualBox VMs/
root@jericho:/home/hipo/VirtualBox VMs# ls
Debian 6  Debian 9  Windows 10
root@jericho:/home/hipo/VirtualBox VMs# cd Debian 6/
r
oot@jericho:/home/hipo/VirtualBox VMs/Debian 6# ls
Debian 6.vbox  Debian 6.vbox-prev  Debian 6.vdi  Logs  NewVirtualDisk1.vdi  Snapshots

root@jericho:/home/hipo/VirtualBox VMs/Debian 6# VBoxManage modifyhd Debian 6.vdi –resize 20000
0%…10%…20%…30%…40%…50%…60%…70%…80%…90%…100%
root@jericho:/home/hipo/VirtualBox VMs/Debian 6#


 

Above command does resize the 10GB default created partition for Linux, where I have installed Linux which was 99% full of data, because of the many packages I installed to 20GB size, to make it bigger just use the respective size, be it 30000 (for 30GB) or 100000 (for 100GB) etc.

Even though in this example VBoxManage virtual partition resize command was done for GNU / Linux Operating System, it can be done for any other Operating as well to resize the size of the Virtual .VDI file (Virtual Machine) partition, be it Windows 7 / 8 / 10 or the rest of Free Operating systems FreeBSD / OpenBSD / BSD that are installed in a VM etc.

Next Launch the Virtual Machine with VBox Server client Program and install there Gparted (GNU Parted), as we'll need it to create a new Hard Disk Partition:

 

$ VirtualBox

 


Inside virtualmachine's in gnome-terminal / xterm etc. depending on the graphical environment used do install with apt-get:

 

debian:# apt-get install –yes gparted

 

debian~:# gparted


Notice that gparted has to be ran as a root superuser.

 

Run GParted and create new EXT3 filesystem that is 10GB (the size of the new created partition).

If you have installed Debian to place all partitions under / (root directory /dev/sda1) then the fresh new partition to create should be
/dev/sda3, anyways just look closely in EXT3 and in your case if the partiition is named differently create according to proper partition /dev/ naming.

I'll not run into details on how to create the partition with GParted as the program interface is very self-explanatory, the only thing is to apply the update to create partition and the ext3 filesystem, that's being done
with a green tick:

gparted-create-ext3-partition-howto-linux

Next step is to check with fdisk whether, we have ext3 properly created  filesystem as we've done already with GPARTED:

Once we have the partition created with EXT3 filesystem, we're ready to move /usr temporary to other folder, I use usually /root for the move but you can create anywhere a new folder for that and move to there.

To move to /root directory run again in terminal:

 

debian:~# mv /usr /root
debian:~# mkdir /usr

 

howto-extend-root-filesystem-disk-space-linux-move-usr-folder-to-root-temporary-debian-gnu-linux

 

Note that during the move operations, your Desktop icons will become without (with broken) pictures and the default Debian background picture is to disappear, that's because the GUI environment will soon realize /usr/ libraries that're periodically reloaded in memory are missing and will be unable to reload them as it does in a cycle.

That should take a few minutes, so grab a coffee or if you're a smoker (hope not as smoking kills 🙂 ), in 5 / 10 minutes time depending on your computer / server configuration, it will be over, so we're ready to create new /usr dir and mount the  new partition:

 

debian:~# mount /dev/sda3 /usr

 

howto-extend-root-filesystem-disk-space-linux-move-usr-folder-to-root-temporary-debian-gnu-linux1

 

Now we check with mount command whether mount is fine:

 

check-if-filesystem-is-properly-mounted-linux-debian-screenshot


Now  /dev/sda3 is mounted under /usr  and we have to move back /root/usr directory content back to the newly mounted /usr so we run command:
 

debian:~#  mv /root/usr/* /usr/*


Finally we need to create proper records for the new partition inside /etc/fstab (fstab –FileSystem Tab file – the file which describes instructs the Linux OS what partition to boot where, what)

HOW TO CHECK LINUX UUID FOR A PARTITION??

Before adding anything to /etc/fstab you need to check the UUID of /dev/sda3 (or whatever the partition is called), without proper UUID, the system might fail to boot.
So here is how to check the UUID we'll need for config:

 

hipo@debian:~$ /sbin/blkid /dev/sda3
/dev/sda3: UUID="2273db4b-3069-4f78-90fc-e7483c0305bd" SEC_TYPE="ext2" TYPE="ext3"

hipo@debian:~$ ls -al /dev/disk/by-uuid/
total 0
drwxr-xr-x 2 root root 100 Oct  6 05:16 .
drwxr-xr-x 6 root root 120 Oct  6 05:16 ..
lrwxrwxrwx 1 root root  10 Oct  6 05:16 2273db4b-3069-4f78-90fc-e7483c0305bd -> ../../sda3
lrwxrwxrwx 1 root root  10 Oct  6 05:16 b98d92cd-41aa-4e18-a474-9b8df445dbe5 -> ../../sda1
lrwxrwxrwx 1 root root  10 Oct  6 05:16 f27f7448-f200-4983-b54f-b9e5206f77ac -> ../../sda5

As you can see our /dev/sda3 UUID is 2273db4b-3069-4f78-90fc-e7483c0305bd

Further on lets view and edit /etc/fstab you can also download a copy of my Virtual Machine fstab here

 

debian:~# cat /etc/fstab

# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
proc            /proc           proc    defaults        0       0
# / was on /dev/sda1 during installation
UUID=b98d92cd-41aa-4e18-a474-9b8df445dbe5 /               ext3    errors=remount-ro 0       1
# swap was on /dev/sda5 during installation
UUID=f27f7448-f200-4983-b54f-b9e5206f77ac none            swap    sw              0       0
/dev/scd0       /media/cdrom0   udf,iso9660 user,noauto     0       0
/dev/scd1       /media/cdrom1   udf,iso9660 user,noauto     0       0


We need to add following line to  /etc/fstab:
 

UUID=2273db4b-3069-4f78-90fc-e7483c0305bd    /usr        ext3 error=remount-ro    0    1

 


Open the file with your favourite text editor (gedit / nano / pico / vim / joe) etc.

debian:~# vim /etc/fstab

 

# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
proc            /proc           proc    defaults        0       0
# / was on /dev/sda1 during installation
UUID=b98d92cd-41aa-4e18-a474-9b8df445dbe5 /               ext3    errors=remount-ro 0       1
# swap was on /dev/sda5 during installation
UUID=f27f7448-f200-4983-b54f-b9e5206f77ac none            swap    sw              0       0
/dev/scd0       /media/cdrom0   udf,iso9660 user,noauto     0       0
/dev/scd1       /media/cdrom1   udf,iso9660 user,noauto     0       0

UUID=2273db4b-3069-4f78-90fc-e7483c0305bd     /usr        ext3 error=remount-ro    0    1    

Basicly it should be possible to add (for historic reasons) also instead of UUID=2273db4b-3069-4f78-90fc-e7483c0305bd  /dev/sda3
So it looks like so but, the better practice is to use UUID line given.

Well that's all folks now /usr directory will contain all your heavy root partition (disk filling) libraries and files, so you can happily use /var/lib/mysql or /var/lib/postgresql /var/www to store your web application files and import your databases.

Big thanks to Ubuntu Forums article – How do I increase the hard disk size of the Virtual Machine article for inspiring this post.

Hope that helps anyone and thanks and other comments are always welcome ! 🙂

Block Web server over loading Bad Crawler Bots and Search Engine Spiders with .htaccess rules

Monday, September 18th, 2017

howto-block-webserver-overloading-bad-crawler-bots-spiders-with-htaccess-modrewrite-rules-file

In last post, I've talked about the problem of Search Index Crawler Robots aggressively crawling websites and how to stop them (the article is here) explaning how to raise delays between Bot URL requests to website and how to completely probhit some bots from crawling with robots.txt.

As explained in article the consequence of too many badly written or agressive behaviour Spider is the "server stoning" and therefore degraded Web Server performance as a cause or even a short time Denial of Service Attack, depending on how well was the initial Server Scaling done.

The bots we want to filter are not to be confused with the legitimate bots, that drives real traffic to your website, just for information

 The 10 Most Popular WebCrawlers Bots as of time of writting are:
 

1. GoogleBot (The Google Crawler bots, funnily bots become less active on Saturday and Sundays :))

2. BingBot (Bing.com Crawler bots)

3. SlurpBot (also famous as Yahoo! Slurp)

4. DuckDuckBot (The dutch search engine duckduckgo.com crawler bots)

5. Baiduspider (The Chineese most famous search engine used as a substitute of Google in China)

6. YandexBot (Russian Yandex Search engine crawler bots used in Russia as a substitute for Google )

7. Sogou Spider (leading Chineese Search Engine launched in 2004)

8. Exabot (A French Search Engine, launched in 2000, crawler for ExaLead Search Engine)

9. FaceBot (Facebook External hit, this crawler is crawling a certain webpage only once the user shares or paste link with video, music, blog whatever  in chat to another user)

10. Alexa Crawler (la_archiver is a web crawler for Amazon's Alexa Internet Rankings, Alexa is a great site to evaluate the approximate page popularity on the internet, Alexa SiteInfo page has historically been the Swift Army knife for anyone wanting to quickly evaluate a webpage approx. ranking while compared to other pages)

Above legitimate bots are known to follow most if not all of W3C – World Wide Web Consorium (W3.Org) standards and therefore, they respect the content commands for allowance or restrictions on a single site as given from robots.txt but unfortunately many of the so called Bad-Bots or Mirroring scripts that are burning your Web Server CPU and Memory mentioned in previous article are either not following /robots.txt prescriptions completely or partially.

Hence with the robots.txt unrespective bots, the case the only way to get rid of most of the webspiders that are just loading your bandwidth and server hardware is to filter / block them is by using Apache's mod_rewrite through

 

.htaccess


file

Create if not existing in the DocumentRoot of your website .htaccess file with whatever text editor, or create it your windows / mac os desktop and transfer via FTP / SecureFTP to server.

I prefer to do it directly on server with vim (text editor)

 

 

vim /var/www/sites/your-domain.com/.htaccess

 

RewriteEngine On

IndexIgnore .htaccess */.??* *~ *# */HEADER* */README* */_vti*

SetEnvIfNoCase User-Agent "^Black Hole” bad_bot
SetEnvIfNoCase User-Agent "^Titan bad_bot
SetEnvIfNoCase User-Agent "^WebStripper" bad_bot
SetEnvIfNoCase User-Agent "^NetMechanic" bad_bot
SetEnvIfNoCase User-Agent "^CherryPicker" bad_bot
SetEnvIfNoCase User-Agent "^EmailCollector" bad_bot
SetEnvIfNoCase User-Agent "^EmailSiphon" bad_bot
SetEnvIfNoCase User-Agent "^WebBandit" bad_bot
SetEnvIfNoCase User-Agent "^EmailWolf" bad_bot
SetEnvIfNoCase User-Agent "^ExtractorPro" bad_bot
SetEnvIfNoCase User-Agent "^CopyRightCheck" bad_bot
SetEnvIfNoCase User-Agent "^Crescent" bad_bot
SetEnvIfNoCase User-Agent "^Wget" bad_bot
SetEnvIfNoCase User-Agent "^SiteSnagger" bad_bot
SetEnvIfNoCase User-Agent "^ProWebWalker" bad_bot
SetEnvIfNoCase User-Agent "^CheeseBot" bad_bot
SetEnvIfNoCase User-Agent "^Teleport" bad_bot
SetEnvIfNoCase User-Agent "^TeleportPro" bad_bot
SetEnvIfNoCase User-Agent "^MIIxpc" bad_bot
SetEnvIfNoCase User-Agent "^Telesoft" bad_bot
SetEnvIfNoCase User-Agent "^Website Quester" bad_bot
SetEnvIfNoCase User-Agent "^WebZip" bad_bot
SetEnvIfNoCase User-Agent "^moget/2.1" bad_bot
SetEnvIfNoCase User-Agent "^WebZip/4.0" bad_bot
SetEnvIfNoCase User-Agent "^WebSauger" bad_bot
SetEnvIfNoCase User-Agent "^WebCopier" bad_bot
SetEnvIfNoCase User-Agent "^NetAnts" bad_bot
SetEnvIfNoCase User-Agent "^Mister PiX" bad_bot
SetEnvIfNoCase User-Agent "^WebAuto" bad_bot
SetEnvIfNoCase User-Agent "^TheNomad" bad_bot
SetEnvIfNoCase User-Agent "^WWW-Collector-E" bad_bot
SetEnvIfNoCase User-Agent "^RMA" bad_bot
SetEnvIfNoCase User-Agent "^libWeb/clsHTTP" bad_bot
SetEnvIfNoCase User-Agent "^asterias" bad_bot
SetEnvIfNoCase User-Agent "^httplib" bad_bot
SetEnvIfNoCase User-Agent "^turingos" bad_bot
SetEnvIfNoCase User-Agent "^spanner" bad_bot
SetEnvIfNoCase User-Agent "^InfoNaviRobot" bad_bot
SetEnvIfNoCase User-Agent "^Harvest/1.5" bad_bot
SetEnvIfNoCase User-Agent "Bullseye/1.0" bad_bot
SetEnvIfNoCase User-Agent "^Mozilla/4.0 (compatible; BullsEye; Windows 95)" bad_bot
SetEnvIfNoCase User-Agent "^Crescent Internet ToolPak HTTP OLE Control v.1.0" bad_bot
SetEnvIfNoCase User-Agent "^CherryPickerSE/1.0" bad_bot
SetEnvIfNoCase User-Agent "^CherryPicker /1.0" bad_bot
SetEnvIfNoCase User-Agent "^WebBandit/3.50" bad_bot
SetEnvIfNoCase User-Agent "^NICErsPRO" bad_bot
SetEnvIfNoCase User-Agent "^Microsoft URL Control – 5.01.4511" bad_bot
SetEnvIfNoCase User-Agent "^DittoSpyder" bad_bot
SetEnvIfNoCase User-Agent "^Foobot" bad_bot
SetEnvIfNoCase User-Agent "^WebmasterWorldForumBot" bad_bot
SetEnvIfNoCase User-Agent "^SpankBot" bad_bot
SetEnvIfNoCase User-Agent "^BotALot" bad_bot
SetEnvIfNoCase User-Agent "^lwp-trivial/1.34" bad_bot
SetEnvIfNoCase User-Agent "^lwp-trivial" bad_bot
SetEnvIfNoCase User-Agent "^Wget/1.6" bad_bot
SetEnvIfNoCase User-Agent "^BunnySlippers" bad_bot
SetEnvIfNoCase User-Agent "^Microsoft URL Control – 6.00.8169" bad_bot
SetEnvIfNoCase User-Agent "^URLy Warning" bad_bot
SetEnvIfNoCase User-Agent "^Wget/1.5.3" bad_bot
SetEnvIfNoCase User-Agent "^LinkWalker" bad_bot
SetEnvIfNoCase User-Agent "^cosmos" bad_bot
SetEnvIfNoCase User-Agent "^moget" bad_bot
SetEnvIfNoCase User-Agent "^hloader" bad_bot
SetEnvIfNoCase User-Agent "^humanlinks" bad_bot
SetEnvIfNoCase User-Agent "^LinkextractorPro" bad_bot
SetEnvIfNoCase User-Agent "^Offline Explorer" bad_bot
SetEnvIfNoCase User-Agent "^Mata Hari" bad_bot
SetEnvIfNoCase User-Agent "^LexiBot" bad_bot
SetEnvIfNoCase User-Agent "^Web Image Collector" bad_bot
SetEnvIfNoCase User-Agent "^The Intraformant" bad_bot
SetEnvIfNoCase User-Agent "^True_Robot/1.0" bad_bot
SetEnvIfNoCase User-Agent "^True_Robot" bad_bot
SetEnvIfNoCase User-Agent "^BlowFish/1.0" bad_bot
SetEnvIfNoCase User-Agent "^JennyBot" bad_bot
SetEnvIfNoCase User-Agent "^MIIxpc/4.2" bad_bot
SetEnvIfNoCase User-Agent "^BuiltBotTough" bad_bot
SetEnvIfNoCase User-Agent "^ProPowerBot/2.14" bad_bot
SetEnvIfNoCase User-Agent "^BackDoorBot/1.0" bad_bot
SetEnvIfNoCase User-Agent "^toCrawl/UrlDispatcher" bad_bot
SetEnvIfNoCase User-Agent "^WebEnhancer" bad_bot
SetEnvIfNoCase User-Agent "^TightTwatBot" bad_bot
SetEnvIfNoCase User-Agent "^suzuran" bad_bot
SetEnvIfNoCase User-Agent "^VCI WebViewer VCI WebViewer Win32" bad_bot
SetEnvIfNoCase User-Agent "^VCI" bad_bot
SetEnvIfNoCase User-Agent "^Szukacz/1.4" bad_bot
SetEnvIfNoCase User-Agent "^QueryN Metasearch" bad_bot
SetEnvIfNoCase User-Agent "^Openfind data gathere" bad_bot
SetEnvIfNoCase User-Agent "^Openfind" bad_bot
SetEnvIfNoCase User-Agent "^Xenu’s Link Sleuth 1.1c" bad_bot
SetEnvIfNoCase User-Agent "^Xenu’s" bad_bot
SetEnvIfNoCase User-Agent "^Zeus" bad_bot
SetEnvIfNoCase User-Agent "^RepoMonkey Bait & Tackle/v1.01" bad_bot
SetEnvIfNoCase User-Agent "^RepoMonkey" bad_bot
SetEnvIfNoCase User-Agent "^Zeus 32297 Webster Pro V2.9 Win32" bad_bot
SetEnvIfNoCase User-Agent "^Webster Pro" bad_bot
SetEnvIfNoCase User-Agent "^EroCrawler" bad_bot
SetEnvIfNoCase User-Agent "^LinkScan/8.1a Unix" bad_bot
SetEnvIfNoCase User-Agent "^Keyword Density/0.9" bad_bot
SetEnvIfNoCase User-Agent "^Kenjin Spider" bad_bot
SetEnvIfNoCase User-Agent "^Cegbfeieh" bad_bot

 

<Limit GET POST>
order allow,deny
allow from all
Deny from env=bad_bot
</Limit>

 


Above rules are Bad bots prohibition rules have RewriteEngine On directive included however for many websites this directive is enabled directly into VirtualHost section for domain/s, if that is your case you might also remove RewriteEngine on from .htaccess and still the prohibition rules of bad bots should continue to work
Above rules are also perfectly suitable wordpress based websites / blogs in case you need to filter out obstructive spiders even though the rules would work on any website domain with mod_rewrite enabled.

Once you have implemented above rules, you will not need to restart Apache, as .htaccess will be read dynamically by each client request to Webserver

2. Testing .htaccess Bad Bots Filtering Works as Expected


In order to test the new Bad Bot filtering configuration is working properly, you have a manual and more complicated way with lynx (text browser), assuming you have shell access to a Linux / BSD / *Nix computer, or you have your own *NIX server / desktop computer running
 

Here is how:
 

 

lynx -useragent="Mozilla/5.0 (compatible; MegaIndex.ru/2.0; +http://megaindex.com/crawler)" -head -dump http://www.your-website-filtering-bad-bots.com/

 

 

Note that lynx will provide a warning such as:

Warning: User-Agent string does not contain "Lynx" or "L_y_n_x"!

Just ignore it and press enter to continue.

Two other use cases with lynx, that I historically used heavily is to pretent with Lynx, you're GoogleBot in order to see how does Google actually see your website?
 

  • Pretend with Lynx You're GoogleBot

 

lynx -useragent="Mozilla/5.0 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)" -head -dump http://www.your-domain.com/

 

 

  • How to Pretend with Lynx Browser You are GoogleBot-Mobile

 

lynx -useragent="Mozilla/5.0 (iPhone; U; CPU iPhone OS 4_1 like Mac OS X; en-us) AppleWebKit/532.9 (KHTML, like Gecko) Version/4.0.5 Mobile/8B117 Safari/6531.22.7 (compatible; Googlebot-Mobile/2.1; +http://www.google.com/bot.html)" -head -dump http://www.your-domain.com/

 


Or for the lazy ones that doesn't have Linux / *Nix at disposal you can use WannaBrowser website

Wannabrowseris a web based browser emulator which gives you the ability to change the User-Agent on each website req1uest, so just set your UserAgent to any bot browser that we just filtered for example set User-Agent to CheeseBot

The .htaccess rule earier added once detecting your browser client is coming in with the prohibit browser agent will immediately filter out and you'll be unable to access the website with a message like:
 

HTTP/1.1 403 Forbidden

 

Just as I've talked a lot about Index Bots, I think it is worthy to also mention three great websites that can give you a lot of Up to Date information on exact Spiders returned user-agent, common known Bot traits as well as a a current updated list with the Bad Bots etc.

Bot and Browser Resources information user-agents, bad-bots and odd Crawlers and Bots specifics

1. botreports.com
2. user-agents.org
3. useragentapi.com

 

An updated list with robots user-agents (crawler-user-agents) is also available in github here regularly updated by Caia Almeido

There are also a third party plugin (modules) available for Website Platforms like WordPress / Joomla / Typo3 etc.

Besides the listed on these websites as well as the known Bad and Good Bots, there are perhaps a hundred of others that might end up crawling your webdsite that might or might not need  to be filtered, therefore before proceeding with any filtering steps, it is generally a good idea to monitor your  HTTPD access.log / error.log, as if you happen to somehow mistakenly filter the wrong bot this might be a reason for Website Indexing Problems.

Hope this article give you some valueable information. Enjoy ! 🙂

 

Install JBL Go Bluetooth Speaker on Debian GNU / Linux and Ubuntu

Thursday, August 24th, 2017

jbl-go-on-gnu-how-to-install-on-debian-and-ubuntu-linux

Here is how to configure a JBL Go Bluetooth (Wireless) speaker and presumably other Bluetooth external speakers to Debian GNU / Linux Wheezy 7 and Ubuntu 14.04 . 1. Install following bunch of deb packages

debian:~# apt-get install pulseaudio pulseaudio-module-bluetooth pavucontrol bluez-firmware

Here it is notable to mention pavucontrol if you have previously played more extensively on GNU / Linux you should have already used if not it is really cozy volume control tool with a lot of tuning options regarding pulseaudio stream server. Considering that like me you're using a GNOME as a desktop environment you will also need gnome-bluetooth package, e.g.:

debian:~# apt-get install gnome-bluetooth

As Pulseaudio is used as a sound streaming server in GNU / Linux (assuming your Debian version is using it you'll also need to have installed pulseaudio-module-bluetooth)

debian:~# apt-get install pulseaudio-module

For Ubuntu 14.04 GNU / Linux users the list of necessery bluetooth packages is a bit longer, if you're on this OS go and install:

debian:~# apt-get install bluez bluez-alsa bluez-audio bluez-btsco bluez-compat bluez-cups bluez-dbg bluez-gstreamer bluez-hcidump bluez-pcmcia-support bluez-tools bluez-utils python-bluez bluewho indicator-bluetooth libbluetooth-dev libgnome-bluetooth11 libbluetooth3 python-gobject python-dbus

Moreover you will need pulseaudio-module-bluetooth deb package installed in order to be able to select the desired sound output.

Next it is time to restart Bluetooth service

debian:~# service bluetooth restart
[ ok ] Stopping bluetooth: rfcomm /usr/sbin/bluetoothd.
[ ok ] Starting bluetooth: bluetoothd rfcomm.

It is also a good idea to restart pulseaudio snd streaming server in order to load the newly installed pulseaudio bluetooth module settings, to do so issue:

debian:~# killall pulseaudio

And try to establish connection from Gnome-Bluetooth to the JBL Go (press the JBL Go bluetooth button) and search from the Linux bluetooth interface, once founded connect it.

bluetooth-new-device-setup

jbl-go-connected-screenshot

Before JBL Go appears to list listable blootooth devices you will also need to run following command:

debian:~# pactl load-module module-bluetooth-discover
26

This command is to connect bluetooth discovered JBL Go device to the audio sink interface.

It is generally idea to add this line also to /etc/rc.local to make the setting permanently executed on every Linux boot.

Now you can launch pavucontrol and hopefully the JBL GO bluetooth speaker should be visible as an option, check out my below screenshot:

 


In case you further experience issues connecting the Bluetooth Speaker I would recommend to check out this Debian a2dp page at the end of the page are troubleshooting suggestions.

Troubleshooting

Refused to switch profile to a2dp_sink: Not connected

Bluetooth headset is connected, but ALSA/PulseAudio fails to pick up the connected device or there's no device to pick. This happens because GDM captures A2DP sink on session start, as GDM needs pulseaudio in the gdm session for accessibility. For example, the screen reader requires it. See 805414 for some discussion.

 

Workaround 1: disable pulseaudio in gdm

In order to prevent GDM from capturing the A2DP sink on session start, edit /var/lib/gdm3/.config/pulse/client.conf (or create it, if it doesn't exist):

 

autospawn = no
daemon-binary = /bin/true

After that you have to grant access to this file to Debian-gdm user:

 

chown Debian-gdm:Debian-gdm /var/lib/gdm3/.config/pulse/client.conf

You will also need to disable pulseaudio startup:

 

rm /var/lib/gdm3/.config/systemd/user/sockets.target.wants/pulseaudio.socket

In order to auto-connect a2dp for some devices, add this to /etc/pulse/default.pa:

 

load-module module-switch-on-connect

Logout your Desktop environment and restart gdm3 /etc/init.d/gdm3 restart or Reboot the PC and then it should be fine.

 

Now the sound device (bluetooth headset) should be accessible through pavucontrol and standard audio device manager.

 

Workaround 2: disable pulseaudio's bluetooth in gdm

The actual solution package maintainers are looking into next is to simply disable the bluetooth sink in the gdm pulseaudio daemon so that it doesn't take over the device. Add this to /var/lib/gdm3/.config/pulse/default.pa:

 

#!/usr/bin/pulseaudio -nF
#

# load system wide configuration
.include /etc/pulse/default.pa

### unload driver modules for Bluetooth hardware
.ifexists module-bluetooth-policy.so
  unload-module module-bluetooth-policy
.endif

.ifexists module-bluetooth-discover.so
  unload-module module-bluetooth-discover
.endif

Though this article explains how to connect a bluetooth speaker connecting Bluetooth Speaker to GNU / Linux is done in analogous way