In one of my previous articles I presented how to:
Configure a bridge interface over a VLAN tagged bonded interface on CentOS / RHEL
This is a supplement to the above tutorial – sometimes all you need is to configure just a regular interface over a VLAN tagged bond and the below procedure describes how to do it on CentOS 7 / RHEL 7 in few easy steps.
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Linux enables us to create advanced network setups which provide us with special features like NIC Bonding, VLAN tagging or Bridging allowing us to increase network connectivity efficiency and reliability of Linux based hosts.
Linux Bond is a kernel module which facilitates combining multiple network interfaces (like ens1f0, ens1f1) into aggregated links named Bonds to provide network redundancy, link failover and increased throughput.
VLAN tagging (802.1q) helps us to distinguish particular VLANs from network trunk (VLANs range) coming from the switch. It’s very helpful Linux kernel module, which enables us to connect to the multiple networks, if the server has less NICs than networks.
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If you have important production servers or critical services in your network, having monitoring tools becomes a must. In case of any hardware or software failures, it is crucial to get alerted as soon as possible and take appropriate actions to fix the failure.
In this article I would like to take a look at checkmk – a powerful monitoring software, developed by tribe29 GmbH with tons of configuration options and a user-friendly WebGUI, which can help you fully automate monitoring activities of your hardware and operating systems.
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Postfix is a Mail Transport Agent (MTA), which can be easily configured as a private relay host, passing mail to other mail servers. Unlike Sendmail, Postfix is considered a very secure MTA, offering a high level of flexibility and ease of administration.
In this article, I am configuring Postfix on CentOS 8, running on CinderCloud VPS, as SMTP smart host (relay host) using SASL authentication to send out mail further to the OVH mail server.
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Sendmail is easy to implement, lightweight electronic Mail Transport Agent (MTA), which enables you to automate the process of sending e-mail messages from your Linux host. It can play a significant role as a background mechanism for processing outbound emails from monitoring software to deliver status notifications to the system administrators or send diagnostic information at a specified time schedule.
In this article, I present how to install and configure Sendmail on CentOS 8 to work as SMTP Relay for outbound traffic to the OVH mail server.
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Using a high-availability LAMP (Linux Apache MySQL/MariaDB PHP) server may totally eliminate the risk of server’s downtime, which can be crucial in case of a production HTTP server, serving critical business application. We can set a redundant, fully functional, high-avalability production HTTP server for free, using well known and proven technologies like Apache server, MariaDB/Galera cluster software and HAProxy load balancer.
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Nextcloud is a lightweight, open-source StaaS (Storage as a Service) platform, written i PHP and JavaScript, which provides file sync, file sharing and creative collaboration services. The software can be installed on local hardware as a perfect alternative for commercial StaaS solutions like Dropbox, OneDrive, Hightail, etc…
Nextcloud is a typical LAMP (Linux Apache MySQL PHP) software, but instead of ardous and problematic LAMP environment installation and file sharing platform implementation, we can deploy a turnkey Nextcloud platform in just a few minutes, using Docker containers, preferably with docker-compose.
In this article I am launching Nextcloud platform in two Docker containers: nextcloud and mariadb which use local Docker volumes as a file and database storage. This solution will enable us to quickly and painlessly upgrade our Nextcloud to a newer versions in future.
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The basic OpenStack TripleO deployment utilises the so called provisioning / control plane network for all types of traffic (internal API, tenant, storage, storage management, etc…), that run across the whole OpenStack installation. The Undercloud node, which is used for Overcloud deployment, becomes a kind of a gateway for Overcloud nodes to the external network. This solution has a major disadventage: the single point of access which is here the Undercloud node, can quickly turn into a single point of failure, if Undercloud fails, cutting us out from Overcloud nodes. Moreover, any diagnostic steps, in case of network issues, bottle necks, etc., become more difficult , since all the traffic runs in one big tube, which is provisioning / control plane network.
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Linux installation can be performed totally unattended using Kickstart file, which contains configuration, required setup and post installation tasks to fully automate installation process without being prompted for any input details. Kickstart file can be placed in the remote repository or can be included in ISO image in order to be read by Anaconda installer during system installation.
In this tutorial we present some practical solutions that can be placed in kickstart file to automate CentOS 7 / Red Hat 7 installation tasks.
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In TripleO based installations of OpenStack the deployment of Overcloud nodes is coordinated by so called Ironic module, which was developed in general to deploy OS on bare metal servers. There is a number of IPMI (Intelligent Platform Management Interface) drivers supported by Ironic, like pxe_ilo for HP Proliant Gen8+, pxe_drac for DELL 12G+, ipmi for generic servers, etc… In case of the generic ipmi driver, Ironic script, which is installed on undercloud (or OSP director), uses a Linux command line ipmitool to send IPMI messages to the Overcloud nodes to control them during TripleO deployment.
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