SSH banner messages are necessary when you want to display a warning for users when they access a server over SSH.
wipefs can erase filesystem, raid or partition-table signatures (magic strings) from the specified device to make the signatures invisible for libblkid.
Erase all available signatures. The set of erased signatures can be restricted with the -t list option.
Force erasure, even if the filesystem is mounted. This is required in order to erase the partition table on a block device.
$ wipefs -a /dev/nvme0n1
Update System Packages
$ sudo apt update
This command retrieves information about the latest available package versions from the repositories configured on the system.
Run the upgrade
Run the following command to upgrade the installed packages, including the kernel, to the latest versions available in the repositories:
$ sudo apt upgrade
A context in kubernetes is used to group access parameters under a convenient name. Each context has three parameters: cluster, namespace, and user. By default, the kubectl command-line tool uses parameters from the current context to communicate with the cluster.
iostat is a Linux I/O performance monitoring utility. It’s very commonly used to analyze device utilization.
From man page of iostat in Linux, %util is explained as below.
Percentage of elapsed time during which I/O requests were issued to the device (bandwidth utilization for the device). Device saturation occurs when this value is close to 100%.
I have seen many cases people misuse this metric when to tell if the system runs into disk I/O bottleneck.
One method to connect to the AKS cluster nodes is to create an interactive shell, aka debug pod.
This is a list of top classic coding questions which help understand various data structure and algorithms.