Safe Reboot Of Linux Using Magic SysRq Key
If you are working on kernel development, or device drivers, or running a code that could cause a kernel panic, the SysRq key will be very valuable. The magic SysRq key is a key combination…
Category: server
Remove AWS Cloudinit
When we copy all data from AWS instance without excluding the cloud-init you will see errors as follows but it will continue to boot with success: On Ubuntu 20.04, these steps worked for me to…
Dell EMC PowerEdge RAID Controller CLI Reference Guide
Drive show commands The PERC Command Line Tool supports the following drive show commands: perccli /cx[/ex]/sx show perccli /cx[/eall]/sall show perccli /cx[/ex]/sx|sall show all perccli /cx[/ex]/sall show jbod perccli /cx[/ex]/sx show jbod NOTE: If enclosures are…
SSH Issue no kex alg
So what is happened? What’s causing it? Well, a modern operating system like Debian Jessie is packaged with OpenSSH 6.7 or newer – and OpenSSH 6.7 disables some ciphers, as per changelog http://www.openssh.com/txt/release-6.7 As Russel rightly pointed…
How To Fix “Device eth0 does not seem to be present, delaying initialization” Error on Centos
check network: # ifconfig lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0…
Create Blocking Bad Bots Through Apache in WHM/cPanel
we see a lot of traffic from ‘bad robots’, these bots cause problems such as high server load, server instability and can even lead to Apache crashing. If you run cPanel on your server firstly…
Managing Journal Systemd Ubuntu
By default, systemd-journald ensures older journal records or journal files are deleted in order to keep a certain amount of disk space free. In the Linux Logging with Systemd section, we explain how to control the thresholds…
HTTP/2 Vulnerabilities in Nginx
In August 2019, NGINX Updates Mitigate in many implementations of HTTP/2. NGINX and Cloudflare are aware in this Mandatory case, Fortunately, For who is using Cloudflare as a proxy. you are safe since they are…
Unable to start MySQL on Ubuntu: AVC apparmor=”DENIED” operation=”open”
MySQL on Ubuntu fails to start. The following error messages are shown in the output of the journalctl -xecommand: AVC apparmor=”DENIED” operation=”open” profile=”/usr/sbin/mysqld” name=”/proc/666999/status” pid=666999 comm=”mysqld” requested_mask=”r” denied_mask=”r” fsuid=124 ouid=124AVC apparmor=”DENIED” operation=”open” profile=”/usr/sbin/mysqld” name=”/sys/devices/system/node/” pid=666999 comm=”mysqld”…
Converting between image formats
qemu-img convert: raw, qcow2, qed, vdi, vmdk, vhd The qemu-img convert command can do conversion between multiple formats, including qcow2, qed, raw, vdi, vhd, and vmdk. Image formatArgument to qemu-imgQCOW2 (KVM, Xen)qcow2QED (KVM)qedrawrawVDI (VirtualBox)vdiVHD (Hyper-V)vpcVMDK (VMware)vmdk This example will convert a raw image…