smartd is a daemon (a helper program) that monitors the health of physical hard disk drives that are "Self-Monitoring, Analysis, and Reporting Technology" (S.M.A.R.T.) capable. Almost all HDD or SSD nowadays have a Self-Monitoring, Analysis and Reporting Technology (S.M.A.R.T.) ability, which can gather valuable data on disk drive health. By using the S.M.A.R.T. monitoring tool, we can avoid premature drive failures by detecting potential problems early on. Installing smartd Run the … [Read more...] about How to monitor Disk health with smartd (S.M.A.R.T.)
How To Check a Disk for Bad Blocks or Disk Errors on CentOS / RHEL
Hard disks can fail unexpectedly and it is always best to keep recent backups of all important data. Please keep in mind that even if a current or oncoming failure is detected, there may not be enough time to backup the data. Below are several methods that can be used to identify bad blocks or disk errors in CentOS/RHEL. Using smartctl If there are several I/O errors in /var/log/messages or one simply suspects the hard disks may be failing, smartctl can be a helpful tool in checking them. … [Read more...] about How To Check a Disk for Bad Blocks or Disk Errors on CentOS / RHEL
How to Change the System locale in CentOS / RHEL 5,6
In conversational English, a locale is a place or location. When working with Linux, a locale specifies the way locale-aware programs display certain kinds of data such as times and dates, money and other numeric values, telephone numbers, and measurements. It can also specify collating sequence and printer paper size. There are 3 ways to change the locale on your CentOS/RHEL 5,6 systems: 1. Changing the system wide locale - edit the /etc/sysconfig/i18n file. 2. Changing the locale for a … [Read more...] about How to Change the System locale in CentOS / RHEL 5,6
Run Docker as a non-root user
The Docker containers by default run with the root privilege and so does the application that runs inside the container. This is another major concern from the security perspective because hackers can gain root access to the Docker host by hacking the application running inside the container. Method 1 - Add user to Docker group 1. To run Docker as a non-root user, you have to add your user to the docker group. 2. Create a docker group if there isn't one: $ sudo groupadd docker 3. Add … [Read more...] about Run Docker as a non-root user
How to Configure Btrfs as the Storage Engine in Docker
Docker is an open platform management tool for Linux Containers. It provides a means for developers and system administrators to build and package applications into lightweight containers. Docker uses devicemapper devices as the default storage engine. To use Btrfs as the storage engine, perform the following steps. Note that Red Hat Enterprise Linux (RHEL) removes the Btrfs storage driver from their build of Docker, both on the Extra Packages for Enterprise Linux (EPEL) repository and the … [Read more...] about How to Configure Btrfs as the Storage Engine in Docker
How to check failed or bad login attempts in Linux
Invalid login attempts can be tracked using command lastb provided the file /var/log/wtmp is present. Some of the possible causes for incorrect or bad login attempts are given below: due to typo wrong password has been entered during login. password has changed of user used in cron to connect via ssh. If any hacker is trying to connect using random / common userid. Last login: Sat Apr 21 16:24:24 UTC 2018 on pts/3 Last failed login: Sat Apr 21 17:44:04 UTC 2018 from … [Read more...] about How to check failed or bad login attempts in Linux
How to configure chrony statistics in CentOS / RHEL 7
The log command The chronyd service uses the /etc/chrony.conf configuration file to set synchronization parameters. The default contents of this file contains everything that is needed to set up successful synchronization. To be able to configure the chrony statistics, we need to configure the "log"T command in the /etc/chrony.conf configuration file. The log command indicates that certain information is to be logged. The syntax of the log command is as shown below. log [name] [...] The … [Read more...] about How to configure chrony statistics in CentOS / RHEL 7
How to create Docker Image from a Container and Dockerfile
Docker is an open platform management tool for Linux Containers. It provides a means for developers and system administrators to build and package applications into lightweight containers. Docker consists of the following components: Docker Engine – A portable, lightweight runtime and packaging tool Docker Hub – A cloud service for sharing applications and automating workflows Docker is used to create image-based application containers. Image-based containers package an application with … [Read more...] about How to create Docker Image from a Container and Dockerfile
Beginners Guide to The Docker World
Docker: Introduction Docker is an open platform management tool for Linux Containers. It provides a means for developers and system administrators to build and package applications into lightweight containers. Docker consists of the following components: Docker Engine – A portable, lightweight runtime and packaging tool Docker Hub – A cloud service for sharing applications and automating workflows Docker is used to create image-based application containers. Image-based containers … [Read more...] about Beginners Guide to The Docker World
Beginners Guide to Udev in Linux
Udev is the device manager for the Linux kernel. Udev dynamically creates or removes device node files at boot time in the /dev directory for all types of devices. Udev is now part of systemd as you can see by viewing the “udev” file names included with the systemd RPM package. # rpm -ql systemd | grep udev /etc/udev /etc/udev/hwdb.bin /etc/udev/rules.d /etc/udev/udev.conf /usr/bin/udevadm ... The Udev daemon, systemd-udevd, receives device uevents directly from the kernel whenever a … [Read more...] about Beginners Guide to Udev in Linux