There are some cases, where a failed drive in our RAID array can cause serious issues. For example, due to the failed drive, our Linux system can shutdown and it won't be able to boot again. The GRUB bootloader might also fail and will need to be reinstalled. We have few options, one of which is to reassemble our RAID array from any other Linux LiveCD distribution. Of course, first we need to physically replace the failed drive and then boot to our LiveCD. Once we have booted, we need to install the mdadm tool.
Imagine you are the head sysadmin of an organization, that hold many servers. Managing the log files of each server can be quite challenging, if you are supposed to do it by logging in to each server and manually checking each log file for important events. Fortunately, rsyslog happens to have a functionality, where rsyslog can serve as a client and a servers. With this information in hand, we can now setup one centralized rsyslog server and all of our other servers can act as clients and send their logs to our centralized rsyslog server. The goals of this tutorial is to show you how to set up a rsyslog client and server and test if the configuration is working.
In this short article, I will share an automated script, which will issue free SSL certificate from Let's Encrypt and place automated cronjob for automated renewal afterwards. Let's Encrypt is a free SSL provider, which is growing in popularity quite fast. Issuing an SSL is painless and takes just few minutes. This script will install the necessary tools such as git and python modules to your system and create a custom cronjob that will automatically renew the SSL certificate. Note that this script does not handle automatic web server configuration due to the nature of that topic. There are many web servers available as well as many configurations possible, which cannot be predicted. Still, this script can be useful to some of you.
NGinx is a lightweight web server, that has grown in popularity in the latest years. It is one of the most popular web servers after Apache. It uses different concepts than Apache and can handle large quantities ot bandwidth if configured properly.
In this tutorial, we will build a dynamic module that is not included in the original source. This works with existing installations as well. Note, that we need to download NGinx's source and use the same parameters that have been used to compile it before. Otherwise we might get the error "module is not binary compatible".
You might be asking yourself why you might need such configuration. Well, some Internet Service Providers or hosting companies block the default SMTP port 25. If that is the case and port 25 cannot be unblocked, we can use alternative solutions. Such solution is relaying email via other port such as 587. Google's Gmail offers such capabilities and you can use your own Gmail account in order to send messages from your server. Here is how you can do it with few simple steps:
OpenLDAP is a free, open source implementation of the Lightweight Directory Access Protocol (LDAP) developed by the OpenLDAP Project. It is released under its own BSD-style license called the OpenLDAP Public License. This tool can be used for authenticating users to Linux OpenLDAP clients connected to OpenLDAP centralized server.
Google Drive is a great platform, where you can store your files. It has a limited capacity with the free tier, but hey, if you need more space you can always buy more. Creating backups of the important data is always a good idea and is relevant in 99% of any case. I've written a small script, which will archive the contents of your website and upload it automatically to your Google Drive.
We have already installed Spacewalk server from which we can control all of our systems. In order to do that, we now need to install our client systems and register them to our Spacewalk server.
Spacewalk is an open source Linux systems management software. Spacewalk is the upstream community project, derived from Red Hat Satellite software.
Using Spacewalk, we can easily configure, manage and deploy software packaged to Linux distros such as CentOS, Red Hat, Fedora and such. It has nice web interface, that we can use to monitor the status of software updates on our servers and start update process. Spacewalk provides provisioning capabilities that enables the user to kickstart provision systems and manage and deploy configuration files. This piece of software also has virtualization capabilities to enable you to provision, control, manage, and monitor virtual KVM and Xen guests.