Category: Ubuntu – ServerOK

Uninstall Time Doctor on Ubuntu

January 27, 2020

by ServerOk with No Comment Ubuntu

Time Doctor is an application to track time. To uninstall Time Doctor on Ubuntu, run

sudo /bin/bash -c 'apt purge sfproc; /bin/bash /opt/sfproc/uninstall'

1	sudo /bin/bash -c 'apt purge sfproc; /bin/bash /opt/sfproc/uninstall'

Time doctor run following process

root@pc8:~# ps aux | grep sfp
root      7884  0.0  0.1  72848  4316 pts/1    S    09:53   0:00 sudo -H -u training /bin/bash -l -c export DISPLAY=:0; export XAUTHORITY=/run/user/1004/gdm/Xauthority; export DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1004/bus,guid=be774defc4c97a1711ff06305e2fb38d; export TD_DEVELOPER=; export XDG_CURRENT_DESKTOP=ubuntu:GNOME; export XDG_SESSION_DESKTOP=ubuntu; export XDG_SESSION_ID=2; cd /home/training; /opt/sfproc/SF/sfproc/3.0.64/sfproc &> /dev/null
training  7889  0.0  0.0  19992  3148 pts/1    S    09:53   0:00 /bin/bash -l -c export DISPLAY=:0; export XAUTHORITY=/run/user/1004/gdm/Xauthority; export DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1004/bus,guid=be774defc4c97a1711ff06305e2fb38d; export TD_DEVELOPER=; export XDG_CURRENT_DESKTOP=ubuntu:GNOME; export XDG_SESSION_DESKTOP=ubuntu; export XDG_SESSION_ID=2; cd /home/training; /opt/sfproc/SF/sfproc/3.0.64/sfproc &> /dev/null
training  7893  4.4  1.2 1407988 51724 pts/1   SLl  09:53   0:00 /opt/sfproc/SF/sfproc/3.0.64/sfproc
root      7947  0.0  0.0  21536   976 pts/1    S+   09:54   0:00 grep --color=auto sfp
root@pc8:~#

root@pc8:~# ps aux | grep sfp

root 7884 0.0 0.1 72848 4316 pts/1 S 09:53 0:00 sudo -H -u training /bin/bash -l -c export DISPLAY=:0; export XAUTHORITY=/run/user/1004/gdm/Xauthority; export DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1004/bus,guid=be774defc4c97a1711ff06305e2fb38d; export TD_DEVELOPER=; export XDG_CURRENT_DESKTOP=ubuntu:GNOME; export XDG_SESSION_DESKTOP=ubuntu; export XDG_SESSION_ID=2; cd /home/training; /opt/sfproc/SF/sfproc/3.0.64/sfproc &> /dev/null

training 7889 0.0 0.0 19992 3148 pts/1 S 09:53 0:00 /bin/bash -l -c export DISPLAY=:0; export XAUTHORITY=/run/user/1004/gdm/Xauthority; export DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1004/bus,guid=be774defc4c97a1711ff06305e2fb38d; export TD_DEVELOPER=; export XDG_CURRENT_DESKTOP=ubuntu:GNOME; export XDG_SESSION_DESKTOP=ubuntu; export XDG_SESSION_ID=2; cd /home/training; /opt/sfproc/SF/sfproc/3.0.64/sfproc &> /dev/null

training 7893 4.4 1.2 1407988 51724 pts/1 SLl 09:53 0:00 /opt/sfproc/SF/sfproc/3.0.64/sfproc

root 7947 0.0 0.0 21536 976 pts/1 S+ 09:54 0:00 grep --color=auto sfp

root@pc8:~#

Ubuntu 18.04 MariaDB 10.2 Too many open files

December 13, 2019

by ServerOk with No Comment Ubuntu

On my computer running Ubuntu 18.04, MriaDB stopped working. PHP application i run on my computer failed with error

SQLSTATE[42S02]: Base table or view not found: 1146 Table 'ok_test.feeds' doesn't exist (SQL: select * from `feeds` where `processed` = 0)

1	SQLSTATE[42S02]: Base table or view not found: 1146 Table 'ok_test.feeds' doesn't exist (SQL: select * from `feeds` where `processed` = 0)

Application can’t find the table. So i tried to login to MySQL and see if table is there or not. But i get error

boby@sok-01:~$ mysql
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is 2504
Server version: 10.2.30-MariaDB-1:10.2.30+maria~bionic-log mariadb.org binary distribution

Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

MariaDB [(none)]> show databases;
ERROR 1018 (HY000): Can't read dir of '.' (errno: 24 "Too many open files")
MariaDB [(none)]>

boby@sok-01:~$ mysql

Welcome to the MariaDB monitor. Commands end with ; or \g.

Your MariaDB connection id is 2504

Server version: 10.2.30-MariaDB-1:10.2.30+maria~bionic-log mariadb.org binary distribution

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

MariaDB [(none)]> show databases;

ERROR 1018 (HY000): Can't read dir of '.' (errno: 24 "Too many open files")

MariaDB [(none)]>

Next i checked if this is due to any MySQL upgrade. I found MySQL got updated today

root@sok-01:~# grep mariadb /var/log/dpkg.log
2019-12-13 08:02:46 status triggers-pending mariadb-server-10.2:amd64 1:10.2.29+maria~bionic
2019-12-13 08:02:46 upgrade mariadb-common:all 1:10.2.29+maria~bionic 1:10.2.30+maria~bionic
2019-12-13 08:02:46 status half-configured mariadb-common:all 1:10.2.29+maria~bionic
2019-12-13 08:02:46 status unpacked mariadb-common:all 1:10.2.29+maria~bionic
2019-12-13 08:02:46 status half-installed mariadb-common:all 1:10.2.29+maria~bionic

root@sok-01:~# grep mariadb /var/log/dpkg.log

2019-12-13 08:02:46 status triggers-pending mariadb-server-10.2:amd64 1:10.2.29+maria~bionic

2019-12-13 08:02:46 upgrade mariadb-common:all 1:10.2.29+maria~bionic 1:10.2.30+maria~bionic

2019-12-13 08:02:46 status half-configured mariadb-common:all 1:10.2.29+maria~bionic

2019-12-13 08:02:46 status unpacked mariadb-common:all 1:10.2.29+maria~bionic

2019-12-13 08:02:46 status half-installed mariadb-common:all 1:10.2.29+maria~bionic

To fix this error, run

systemctl edit mysql

1	systemctl edit mysql

This wil open a text editor. Add following

[Service]
LimitNOFILE=8192

1 2	[Service] LimitNOFILE=8192

Save and quit the editor. Restart MaraDB with

systemctl restart mysql

1	systemctl restart mysql

MySQL will work properly now. systemctl edit mysql will create file /etc/systemd/system/mysql.service.d/override.conf

root@sok-01:~# cat /etc/systemd/system/mysql.service.d/override.conf 
[Service]
LimitNOFILE=8192

root@sok-01:~#

root@sok-01:~# cat /etc/systemd/system/mysql.service.d/override.conf

[Service]

LimitNOFILE=8192

root@sok-01:~#

Disable Native Notification on Google Chrome Ubuntu

November 8, 2019

by ServerOk with No Comment Ubuntu

On Ubuntu, Google chrome had a disable native notification option. On Chrome 78, this option is removed. But you still can manually enable it.

To enbale chrome notification, edit file

gedit ~/.config/google-chrome/Local\ State

1	gedit ~/.config/google-chrome/Local\ State

Find

"tab-hover-cards@4"

1	"[email protected]"

Replace with

"enable-native-notifications@2","tab-hover-cards@4"

1	"[email protected]","[email protected]"

Save and exit the file. Now restart google chrome.

Related Posts

Google Chrome

Install NextCloud Desktop client on Ubuntu

September 28, 2019

by ServerOk with No Comment Ubuntu

To install NextCloud desktop client on Ubuntu, add PPA

sudo add-apt-repository ppa:nextcloud-devs/client
sudo apt-get update

1 2	sudo add-apt-repository ppa:nextcloud-devs/client sudo apt-get update

Now run

sudo apt install nextcloud-client

1	sudo apt install nextcloud-client

After install, start nextcloud client, you will be able to login with nextcloud server URL, user and password.

Linux KVM Bridge network on Ubuntu

September 17, 2019

by ServerOk with No Comment Ubuntu

On Ubuntu 18.04 server, first i get Ubuntu to use /etc/network/interface, by default Ubuntu 18.04 and newer use netplan.

First install ifdown

apt install ifupdown -y

1	apt install ifupdown -y

Now you can configure your network interface by editing file

vi  /etc/network/interface

1	vi /etc/network/interface

Here is my network configuration on an OVH server.

root@ns3048991:~# cat /etc/network/interfaces
# interfaces(5) file used by ifup(8) and ifdown(8)
# Include files from /etc/network/interfaces.d:
source-directory /etc/network/interfaces.d

auto eno3
iface eno3 inet static
    address 149.202.199.137
    netmask 255.255.255.255
    broadcast 149.202.199.137
    gateway 149.202.199.254
    dns-nameservers 8.8.8.8 8.8.4.4
root@ns3048991:~#

root@ns3048991:~# cat /etc/network/interfaces

# interfaces(5) file used by ifup(8) and ifdown(8)

# Include files from /etc/network/interfaces.d:

source-directory /etc/network/interfaces.d

auto eno3

iface eno3 inet static

address 149.202.199.137

netmask 255.255.255.255

broadcast 149.202.199.137

gateway 149.202.199.254

dns-nameservers 8.8.8.8 8.8.4.4

root@ns3048991:~#

To convert this interface to bridge network, do the following

1) Replace all occurance of “eno3” with “br0”

2) Add following lines

    bridge_ports eno3
    bridge_stp off
    bridge_maxwait 5

bridge_ports eno3

bridge_stp off

bridge_maxwait 5

In above, replace “eno3” with name of your physical interface.

Here is my final network configuration.

root@ns3048991:~# cat /etc/network/interfaces
# interfaces(5) file used by ifup(8) and ifdown(8)
# Include files from /etc/network/interfaces.d:
source-directory /etc/network/interfaces.d

auto br0
iface br0 inet static
    address 149.202.199.137
    netmask 255.255.255.255
    broadcast 149.202.199.137
    gateway 149.202.199.254
    bridge_ports eno3
    bridge_stp off
    bridge_maxwait 5
    dns-nameservers 8.8.8.8 8.8.4.4
root@ns3048991:~#

root@ns3048991:~# cat /etc/network/interfaces

# interfaces(5) file used by ifup(8) and ifdown(8)

# Include files from /etc/network/interfaces.d:

source-directory /etc/network/interfaces.d

auto br0

iface br0 inet static

address 149.202.199.137

netmask 255.255.255.255

broadcast 149.202.199.137

gateway 149.202.199.254

bridge_ports eno3

bridge_stp off

bridge_maxwait 5

dns-nameservers 8.8.8.8 8.8.4.4

root@ns3048991:~#

See Linux KVM, Networking @ linux-kvm.org

Install Xfce VNC remote desktop on Ubuntu

September 17, 2019

by ServerOk with No Comment Ubuntu

XFCE is a light weight desktop for Linux. XFCE + vnc allow you to setup remote desktop on a VPS or dedicated server located on a data center or cloud. You can connect to remote desktop using VNC client and work like it is local computer.

To instal XFCE run

apt install -y xfce4 xfce4-goodies

1	apt install -y xfce4 xfce4-goodies

Next install vncserver

apt install -y vnc4server

1	apt install -y vnc4server

It is bad idea to use root user for logging into desktop. Create a normal user to run desktop.

useradd -m -s /bin/bash USERNAME_HERE

1	useradd -m -s /bin/bash USERNAME_HERE

It will be good to make this user an admin, so user can install software or update system.

usermod -aG sudo USERNAME_HERE

1	usermod -aG sudo USERNAME_HERE

Now login as the user

su - USERNAME_HERE

1	su - USERNAME_HERE

Create a vnc password for this user.

vncpasswd

vncpasswd

Create vnc startup file

vi ~/.vnc/xstartup

1	vi ~/.vnc/xstartup

Add

#!/bin/bash

xrdb $HOME/.Xresources

/usr/bin/vncconfig -nowin -display :1 &

startxfce4 &

#!/bin/bash

xrdb $HOME/.Xresources

/usr/bin/vncconfig -nowin -display :1 &

startxfce4 &

Make it executable

chmod 755 ~/.vnc/xstartup

1	chmod 755 ~/.vnc/xstartup

Now exit the user with “exit” command. You should be user “root” now.

Create service file

To auto start vncserver on boot, you need to create a service file.

vi  /etc/systemd/system/vncserver@.service

1	vi /etc/systemd/system/vncserver@.service

Add

[Unit]
Description=VNC server startup script
After=syslog.target network.target

[Service]
Type=forking
User=USERNAME_HERE
ExecStartPre=-/usr/bin/vncserver -kill :%i &> /dev/null
ExecStart=/usr/bin/vncserver -depth 24 -geometry 1920x1080 :%i
PIDFile=/home/USERNAME_HERE/.vnc/%H:%i.pid
ExecStop=/usr/bin/vncserver -kill :%i

[Install]
WantedBy=multi-user.target

[Unit]

Description=VNC server startup script

After=syslog.target network.target

[Service]

Type=forking

User=USERNAME_HERE

ExecStartPre=-/usr/bin/vncserver -kill :%i &> /dev/null

ExecStart=/usr/bin/vncserver -depth 24 -geometry 1920x1080 :%i

PIDFile=/home/USERNAME_HERE/.vnc/%H:%i.pid

ExecStop=/usr/bin/vncserver -kill :%i

[Install]

WantedBy=multi-user.target

Enable the service with

systemctl enable vncserver@1

1	systemctl enable vncserver@1

You can start/stop vncserver with

systemctl stop vncserver@1
systemctl start vncserver@1

1 2	systemctl stop vncserver@1 systemctl start vncserver@1

Now reboot the server. You should be able to connect to VNC server using SERVER_IP:1

Install HandBrake on Ubuntu 18.04

September 17, 2019

by ServerOk with No Comment Ubuntu

HandBreak is an OpenSource Video transcoder available from https://handbrake.fr. It can convert video to various format.

Latest version of Handbreak available in Ubuntu PPA. To install, enable Handbreak PPA

add-apt-repository ppa:stebbins/handbrake-releases

1	add-apt-repository ppa:stebbins/handbrake-releases

Install handbreak with

apt install handbrake-gtk handbrake-cli

1	apt install handbrake-gtk handbrake-cli

Install Linux KVM on Ubuntu

September 17, 2019

by ServerOk with No Comment Ubuntu

Linux KVM is virtualisation software that allow you to create virtual machine under linux. To install on Ubuntu, run

apt install -y qemu-kvm

1	apt install -y qemu-kvm

Install libvirtd, this allow you to easily create KVM virtual machines and allow remote connection from virt-manager GUI application.

apt install -y libvirt-bin

1	apt install -y libvirt-bin

Enable and start libvirt

systemctl enable libvirtd
systemctl start libvirtd

1 2	systemctl enable libvirtd systemctl start libvirtd

At this stage, you should be able to connect to KVM server form your computer using virt-manager.

You need to create a bridge network interface (“br0”), for this, follow instructions at Linux KVM Bridge network on Ubuntu.

Downloading ISO

Before you can setup any VM, you need to download ISO image for the OS. Here i downloaded ISO image for Ubuntu 19.04

cd /var/lib/libvirt/images
wget http://mirrors.piconets.webwerks.in/ubuntu-mirror/ubuntu-releases/19.04/ubuntu-19.04-live-server-amd64.iso

1 2	cd /var/lib/libvirt/images wget http://mirrors.piconets.webwerks.in/ubuntu-mirror/ubuntu-releases/19.04/ubuntu-19.04-live-server-amd64.iso

Once downloaded, you should be able to select this ISO image in virt-manager when creating a VM.

See Linux KVM

Set default editor in Ubuntu

September 13, 2019

by ServerOk with No Comment Ubuntu

To set default editor in Ubuntu/Debian, run

update-alternatives --config editor

1	update-alternatives --config editor

Ubuntu default editor

See update-alternatives

Install drivers on Ubuntu

August 31, 2019

by ServerOk with No Comment Ubuntu

To install drivers on Ubuntu using command line, run

boby@sok-01:~$ sudo ubuntu-drivers devices
== /sys/devices/pci0000:00/0000:00:01.1/0000:01:00.0 ==
modalias : pci:v000010DEd00001F82sv00001458sd00003FCBbc03sc00i00
vendor   : NVIDIA Corporation
driver   : nvidia-driver-430 - distro non-free recommended
driver   : xserver-xorg-video-nouveau - distro free builtin

boby@sok-01:~$

boby@sok-01:~$ sudo ubuntu-drivers devices

== /sys/devices/pci0000:00/0000:00:01.1/0000:01:00.0 ==

modalias : pci:v000010DEd00001F82sv00001458sd00003FCBbc03sc00i00

vendor : NVIDIA Corporation

driver : nvidia-driver-430 - distro non-free recommended

driver : xserver-xorg-video-nouveau - distro free builtin

boby@sok-01:~$

This list all drivers available for your hardware. You can install a driver with apt. In this cuase, i have 2 drivers available

driver   : nvidia-driver-430 - distro non-free recommended
driver   : xserver-xorg-video-nouveau - distro free builtin

1 2	driver : nvidia-driver-430 - distro non-free recommended driver : xserver-xorg-video-nouveau - distro free builtin

First driver is recommended by Ubuntu. To install, run

apt install nvidia-driver-430

1	apt install nvidia-driver-430

Install Driver using Software & Updates

Start software and updates application.

Click on Additional Drivers tab. You will see available drivers for your computer.