Linux – IT Blog

Solution apparmor=”DENIED” operation=”open” profile=”/usr/sbin/mysqld”

Once optimizing one of the servers, I executed the command:

dmesg

And I saw the following messages:
Continue reading Solution apparmor=”DENIED” operation=”open” profile=”/usr/sbin/mysqld”

How to install and configure Unbound

I will give an example of installing the Unbound caching DNS server.

You can install Unbound in Ubuntu with the command:
Continue reading How to install and configure Unbound

Setting up BGP in Quagga

AS – Autonomic System.
BGP – Border Gateway Protocol.

You can install quagga in Ubuntu/Debian with the following command:
Continue reading Setting up BGP in Quagga

Solution ZEBRA: netlink-listen recvmsg overrun: No buffer space available

Once on the server with Quagga after adding several thousand network interfaces, I noticed a message in the logs /var/log/zebra.log:

ZEBRA: netlink-listen recvmsg overrun: No buffer space available

Looked at the current values (I everywhere was 212992):
Continue reading Solution ZEBRA: netlink-listen recvmsg overrun: No buffer space available

Setting up nginx logs

I will give examples of setting logging for nginx.

To change the log settings, open the nginx configuration file in any text editor:
Continue reading Setting up nginx logs

Check hardware information on Linux

Below is an example of some commands for viewing information about a computer in Linux.

General information:

sudo apt install lshw
sudo lshw

Continue reading Check hardware information on Linux

How to view information about the network adapter in Linux

I will give examples of commands for viewing information about a network adapter in Linux.

View network interfaces and assigned IP addresses:

ifconfig
ifconfig -a
ifconfig -a | grep ens2f0
ip link show

Continue reading How to view information about the network adapter in Linux

How to install Midnight Commander (MC) on Ubuntu 18.04

Once after installing Ubuntu Server 18.04, when trying to install Midnight Commander, a message was displayed that the package for installation was not found.

To solve the problem, you need to add the Universe repository:
Continue reading How to install Midnight Commander (MC) on Ubuntu 18.04

Installation and information about Midnight Commander on Linux

To install Midnight Commander in Ubuntu/Debian, just run:

sudo apt-get install mc

To install on CentOS:

yum install mc

For start:
mc

I will describe some shortcuts while working in Midnight Commander:
Ctrl+O Switch between command line and mc.
Ctrl+l Updates all displayed information.
Ctrl+x c Runs the Chmod command for the selected object.
Ctrl+x o Runs the Chown command for the selected object.
Ctrl+x l Runs the command to create a hard link.
Ctrl+x s Runs the command to create a symbolic link.
Ctrl+x i Switches the passive panel to the “Information” mode.
Ctrl+x q Switches the passive panel to quick view.
Ctrl+x ! The menu item “Paneling Criteria” is executed.
Ctrl+x h Add the directory name to the “Directory”.
Continue reading Installation and information about Midnight Commander on Linux

Speed limit on network interface using TC

I will give an example of a speed limit of up to 3.3 Gb/s on a network interface on Ubuntu Server 16.04:

/sbin/tc qdisc del dev ens2f0 parent ffff:
/sbin/tc qdisc add dev ens2f0 handle ffff: ingress
/sbin/tc filter add dev ens2f0 parent ffff: protocol ip prio 50 u32 match ip dst 0.0.0.0/0 police rate 3300mbit burst 330k mtu 30000 drop flowid 1:0

Continue reading Speed limit on network interface using TC