Resources, Articles, Tricks, and Solutions in connection to Server Management Service

Manage Networking with NetworkManager in RHEL CentOS 8

This article covers NetworkManager daemon for managing the networking service to dynamically configure and control network devices and keep connections up and active when they are available.
Netstat is a command line utility that can be used to list out all the network (socket) connections on a system.
It lists out all the tcp, udp socket connections and the unix socket connections.
To reboot Linux using the command line: To reboot the Linux system from a terminal session, sign in or “su”/”sudo” to the “root” account.
Then type “ sudo reboot ” to reboot the box. Wait for some time and the Linux server will reboot itself.

To troubleshoot network connectivity with Linux server:
i. Check your network configuration.
ii. Check the network configuration file.
iii. Check the servers DNS records.
iv. Test the connection both ways.
v. Find out where the connection fails.
vi. Firewall settings.
vii. Check Host status information.

To change the hostname in Linux Ubuntu:
i. Type the following command to edit /etc/hostname using nano or vi text editor: sudo nano /etc/hostname. Delete the old name and setup new name.
ii. Next Edit the /etc/hosts file: sudo nano /etc/hosts.
iii. Reboot the system to changes take effect: sudo reboot.

To reinstall #network service in #Linux (#Ubuntu / #Debian):
i. Use the following command to restart the server networking service. # sudo /etc/init.d/networking restart or
# sudo /etc/init.d/networking stop # sudo /etc/init.d/networking start else # sudo systemctl restart networking.
ii. Once this done, use the following command to check the server network status.

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Django Application with Kubernetes

This article covers deploying a Scalable and Secure Django Application. Kubernetes is a powerful open-source container orchestrator.
Kubernetes is a powerful open-source container orchestrator that automates the deployment, scaling and management of containerized applications.
Kubernetes objects like ConfigMaps and Secrets allow you to centralize and decouple configuration from your containers, while controllers like Deployments automatically restart failed containers and enable quick scaling of container replicas.
TLS encryption is enabled with an Ingress object and the ingress-nginx open-source Ingress Controller.
The cert-manager Kubernetes add-on renews and issues certificates using the free Let’s Encrypt certificate authority.

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HTTP Client in Node js

This article covers how to create HTTP Client in Node.js. Here, we performed GET, POST, PUT, and DELETE requests in Node.js. Node HTTP tutorial shows how to create HTTP server and client applications in JavaScript with HTTP module.
HTTP is a Node.js module which can be used to create HTTP server and client applications in JavaScript.
Node.js comes bundled with an http and an https module. These modules have functions to create an HTTP server so that a Node.js program can respond to HTTP requests. They can also make HTTP requests to other servers.
Popular JavaScript frameworks including Express and HapiJS are built on top of the HTTP module.

To Set up HTTP:
1. First, we install the HTTP module.
$ node -v
$ npm init -y
2. We initiate a new Node.js application.
$ npm i http
3. We install HTTP with npm i http command.

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KVM live migration to resolve performance issues

This article covers how to use KVM live migration to achieve load balancing which is important in a server virtualization system to maintain server performance.
Migration enables an administrator to move a virtual machine instance from one compute host to another. A typical scenario is planned maintenance on the source host, but migration can also be useful to redistribute the load when many VM instances are running on a specific physical machine.

Kernel-based Virtual Machine (KVM) is an open source virtualization technology built into Linux.
Specifically, KVM lets you turn #Linux into a #hypervisor that allows a host machine to run multiple, isolated virtual environments called guests or virtual machines (VMs).

Live migration of virtual machines is necessary when you need to achieve high-availability setups and load distribution.
The #KVM hypervisor has been a powerful alternative to Xen and VMware in the Linux world for several years.
To make the virtualization solution suitable for enterprise use, the developers are continually integrating new and useful features.
An example of this is live migration of virtual machines (VMs).

Live #migration involves:
The instance keeps running throughout the migration.
This is useful when it is not possible or desirable to stop the application running on the instance.
Live migrations can be classified further by the way they treat instance storage:
1. Shared storage-based live migration. The instance has ephemeral disks that are located on storage shared between the source and destination hosts.
2. Block live migration, or simply block migration. The instance has ephemeral disks that are not shared between the source and destination hosts. Block migration is incompatible with read-only devices such as CD-ROMs and Configuration Drive (config_drive).
3. Volume-backed live migration. Instances use volumes rather than ephemeral disks.

Block live migration requires copying disks from the source to the destination host.
It takes more time and puts more load on the network. Shared-storage and volume-backed live migration does not copy disks.

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Malicious TMP files and processes

This article covers method to resolve malicious tmp processes. Most malware installers delete itself and these TMP files after successful installation.
The use of TMP files for atomicity is an advantage attackers currently enjoy.
They could have done this operation in any folder of the system, but they choose to use the standard Windows Temp folder.
The first thing a malware installer (first stage of infection) does when executed on a target system - be it a dropper or downloader - is to install a copy of the malware and its components into their corresponding location in the system.

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Install vnStat in Linux to monitor network traffic

This article covers how to install and configure vnStat in Linux. Also, you will see how to resolve some common errors relating to it.
#vnStat (view network statistics) is a network utility for the #Linux operating system.
It uses a command line interface. vnStat command is a console-based network #traffic #monitor.
It keeps a log of hourly, daily and monthly network traffic for the selected interface(s) but is not a packet sniffer.

Features of vnStat:
1. quick and simple to install and get running
2. gathered statistics persists through system reboots
3. can monitor multiple interfaces at the same time
4. data retention duration is fully user configurable on the fly
5. months can be configured to follow billing period
6. light, minimal resource usage
7. same low cpu usage regardless of traffic
8. can be used without root permissions
9. online color configuration editor

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