linux Archives - ServerOK

Docker delete container after running

January 1, 2020

by ServerOk with No Comment Docker

When you run a docker image, it create a container and run it. After docker container stop, container stays, so you can use it again if required.

Some times, you need to delete docker container after it is run. This is useful if your docker container is just a command line executable. In my case, docker container have ffmpeg in it, i don’t want container left over after i executed ffmpeg command.

To auto delete container after execution, use –rm option.

docker run --rm DOCKER_IMAGE

1	docker run --rm DOCKER_IMAGE

Example

docker run --rm --name ffmpeg jrottenberg/ffmpeg:3.2-ubuntu -format

1	docker run --rm --name ffmpeg jrottenberg/ffmpeg:3.2-ubuntu -format

apt force IPv4

December 31, 2019

by ServerOk with No Comment Debian

One of my internet provider only provide IPv4 connection. When i run apt install command, it failed with error as it try to connect using IPv6.

boby@sok-01:~$ sudo apt install php7.3-curl
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following NEW packages will be installed:
  php7.3-curl
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 29.6 kB of archives.
After this operation, 123 kB of additional disk space will be used.
Err:1 http://ppa.launchpad.net/ondrej/php/ubuntu bionic/main amd64 php7.3-curl amd64 7.3.13-1+ubuntu18.04.1+deb.sury.org+1
  Could not connect to ppa.launchpad.net:80 (2001:67c:1560:8008::15). - connect (101: Network is unreachable) Could not connect to ppa.launchpad.net:80 (91.189.95.83), connection timed out
E: Failed to fetch http://ppa.launchpad.net/ondrej/php/ubuntu/pool/main/p/php7.3/php7.3-curl_7.3.13-1+ubuntu18.04.1+deb.sury.org+1_amd64.deb  Could not connect to ppa.launchpad.net:80 (2001:67c:1560:8008::15). - connect (101: Network is unreachable) Could not connect to ppa.launchpad.net:80 (91.189.95.83), connection timed out
E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?
boby@sok-01:~$

boby@sok-01:~$ sudo apt install php7.3-curl

Reading package lists... Done

Building dependency tree

Reading state information... Done

The following NEW packages will be installed:

php7.3-curl

0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.

Need to get 29.6 kB of archives.

After this operation, 123 kB of additional disk space will be used.

Err:1 http://ppa.launchpad.net/ondrej/php/ubuntu bionic/main amd64 php7.3-curl amd64 7.3.13-1+ubuntu18.04.1+deb.sury.org+1

Could not connect to ppa.launchpad.net:80 (2001:67c:1560:8008::15). - connect (101: Network is unreachable) Could not connect to ppa.launchpad.net:80 (91.189.95.83), connection timed out

E: Failed to fetch http://ppa.launchpad.net/ondrej/php/ubuntu/pool/main/p/php7.3/php7.3-curl_7.3.13-1+ubuntu18.04.1+deb.sury.org+1_amd64.deb Could not connect to ppa.launchpad.net:80 (2001:67c:1560:8008::15). - connect (101: Network is unreachable) Could not connect to ppa.launchpad.net:80 (91.189.95.83), connection timed out

E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?

boby@sok-01:~$

To force apt to use IPv4 only, edit

sudo vi /etc/apt/apt.conf.d/99-force-ipv4

1	sudo vi /etc/apt/apt.conf.d/99-force-ipv4

Add

Acquire::ForceIPv4 "true";

1	Acquire::ForceIPv4 "true";

If you want to force IPv6, add

Acquire::ForceIPv6 "true";

1	Acquire::ForceIPv6 "true";

CentOS 7 resolv.conf make changes permanent

December 31, 2019

by ServerOk with No Comment CentOS

On rebooting CentOS 7 server, changes made to resolv.conf is lost. This is becaise one of the network interface is configured to use DNS server.

[root@server ~]# grep DNS /etc/sysconfig/network-scripts/ifcfg-*
/etc/sysconfig/network-scripts/ifcfg-eno1:DNS1="127.0.0.1"
[root@server ~]#

[root@server ~]# grep DNS /etc/sysconfig/network-scripts/ifcfg-*

/etc/sysconfig/network-scripts/ifcfg-eno1:DNS1="127.0.0.1"

[root@server ~]#

To fix, edit

vi /etc/sysconfig/network-scripts/ifcfg-eno1

1	vi /etc/sysconfig/network-scripts/ifcfg-eno1

Remove the line

DNS1="127.0.0.1"

1	DNS1="127.0.0.1"

Now NetworkManager will not modify /etc/resolv.conf file on boot.

Or you can set valid DNS servers in network config file like

[root@server ~]# cat /etc/sysconfig/network-scripts/ifcfg-eno1 | grep DNS
DNS1="1.1.1.1"
DNS2="8.8.8.8"
[root@server ~]#

[root@server ~]# cat /etc/sysconfig/network-scripts/ifcfg-eno1 | grep DNS

DNS1="1.1.1.1"

DNS2="8.8.8.8"

[root@server ~]#

If your network configuration use DHCP, set set PEERDNS=no.

BOOTPROTO=dhcp
PEERDNS=no

1 2	BOOTPROTO=dhcp PEERDNS=no

Another solution is to make file immutable with

chattr +i /etc/resolv.conf

1	chattr +i /etc/resolv.conf

Related Posts

Domain Resolver

Updating Kernel on Oracle Linux with Ksplice

December 20, 2019

by ServerOk with No Comment Linux

Oracle Linux come with Ksplice, it allow you to upgrade Kernel with out rebooting.

To update kernel, run

uptrack-upgrade

1	uptrack-upgrade

Example

Install clamav Antivirus on CentOS 7

December 17, 2019

by ServerOk with No Comment CentOS

ClamAV is provided by EPEL repo. Install epel repo

yum install -y epel-release

1	yum install -y epel-release

Install ClamAV with

yum install clamav

1	yum install clamav

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:~#

OpenLiteSpeed

December 13, 2019

by ServerOk with No Comment Linux

OpenLiteSpeed is open source version of popular commercial web server LiteSpeed. OpenLiteSpeed contains all of the essential features found in LiteSpeed Enterprise.

You can get OpenLiteSpeed from

https://openlitespeed.org

Here is a benchmark from OpenLiteSpeed web site that compare OpenLiteSpeed with Nginx.

OpenLiteSpeed configuration file

/usr/local/lsws/conf/httpd_config.conf

1	/usr/local/lsws/conf/httpd_config.conf

To start/stop/restart, use

/usr/local/lsws/bin/lswsctrl start
/usr/local/lsws/bin/lswsctrl stop
/usr/local/lsws/bin/lswsctrl restart
/usr/local/lsws/bin/lswsctrl status

/usr/local/lsws/bin/lswsctrl start

/usr/local/lsws/bin/lswsctrl stop

/usr/local/lsws/bin/lswsctrl restart

/usr/local/lsws/bin/lswsctrl status

OpenLiteSpeed web server stores cache in directory /usr/local/lsws/cachedata. This can grow big overtime. You can delete this folder to free up space or move it to another partition with free disk space and create a symlink.

Web Server

Linux whois command

December 13, 2019

by ServerOk with No Comment Linux

Linux whois command is used to find who owns a domain or IP address.

To see information about a domain, use

whois DOMAIN_NAME_HERE

1	whois DOMAIN_NAME_HERE

Example

To find information about an IP address, use

whois IP_ADDR_HERE

1	whois IP_ADDR_HERE

Example

whois ip address

Related Posts

Linux Commands

CentOS 7 Grub 2

December 2, 2019

by ServerOk with No Comment CentOS

To regenerate grub config on CentOS 7, run

grub2-mkconfig -o /boot/grub2/grub.cfg

1	grub2-mkconfig -o /boot/grub2/grub.cfg

If you use UEFI, run

grub2-mkconfig -o /boot/efi/EFI/centos/grub.cfg

1	grub2-mkconfig -o /boot/efi/EFI/centos/grub.cfg

yum reinstall a package

December 2, 2019

by ServerOk with No Comment CentOS

To reinstall a package with yum, run

yum reinstall PKG_NAME

1	yum reinstall PKG_NAME

Example

yum reinstall kernel

1	yum reinstall kernel