pgAdmin is the most popular and features rich Open Source administration and development platform for PostgreSQL, the most advanced Open Source database in the world.

Thanks to this application, you can have a graphical interface to manage everything related to PostgreSQL. The main advantage of this program is the ability to view all the records we have stored. On the other hand, we can create connections and customize them to achieve even more security. It is also possible to create, modify, and delete databases.

So, pgAdmin4 becomes a printable application if you use a lot of PostgreSQL or if you want to use it for educational purposes.

So, let us install pgAdmin4 on CentOS 8.

Install PostgreSQL on CentOS 8

The first step we have to do is to have an instance of PostgreSQL up and running on our server. For this we have a post that can help you with this:

How to install PostgreSQL 12 on CentOS 8 / RHEL 8 / Oracle Linux 8?

Once PostgreSQL is correctly installed and configured then we can proceed to install PgAdmin4 without any problems.

Install pgAdmin4 on CentOS 8

The first thing we have to do is update the operating system.

dnf update

Then, enable the EPEL repository that we will need to enhance the installation:

dnf install https://dl.fedoraproject.org/pub/epel/epel-release-latest-8.noarch.rpm

Within this repository, there is one called powertool that we also have to enable.

dnf config-manager --set-enabled powertools

And finally, install pgAdmin4 by running the following command:

dnf --enablerepo=powertools install pgadmin4

After accepting the changes, the download and installation process will begin.

Preparing pgAdmin4 for the firt use

Before using pgAdmin4 it is advisable to make a few settings so as not to have problems of any kind.

First, start and enable the Apache webserver that was installed during the process.

systemctl enable httpd
systemctl start httpd

pgAdmin comes with a default Apache configuration, which we can use or modify. In this case, we will copy it to take advantage of it.

cp /etc/httpd/conf.d/pgadmin4.conf.sample /etc/httpd/conf.d/pgadmin4.conf

Apply the changes by restarting Apache:

systemctl restart httpd

The next step is to create dedicated folders for pgAdmin log and lib. You can choose another location but the most pertinent is /var/

mkdir -p /var/lib/pgadmin4/
mkdir -p /var/log/pgadmin4/

You can then configure pgAdmin4 to tell it to use the paths of the folders you have created.

nano /usr/lib/python3.6/site-packages/pgadmin4-web/config_distro.py

And add the following lines:

LOG_FILE = '/var/log/pgadmin4/pgadmin4.log
SQLITE_PATH = '/var/lib/pgadmin4/pgadmin4.db
SESSION_DB_PATH = '/var/lib/pgadmin4/sessions
STORAGE_DIR = '/var/lib/pgadmin4/storage 

Save the changes, and then close the file.

Now define the username and password that we will use to access pgAdmin4.

python3 /usr/lib/python3.6/site-packages/pgadmin4-web/setup.py 

And there you will have to set the password.

Assign Apache to be the owner of the created directories.

chown -R apache:apache /var/lib/pgadmin4
chown -R apache:apache /var/log/pgadmin4

Apply all changes by restarting Apache and PostgreSQL.

systemctl restart httpd
systemctl restart postgresql-12 

Now we can use it.

Testing the installation

Now we can access http://your-server/pgadmin4 and you should see the following screen

Now login with your credentials and you will see the pgAdmin main screen. This proves that everything works.

All you have to do now is add your PostgreSQL instance.

Conclusion

pgAdmin4 is a vital tool to manipulate PostgreSQL visually and very easily. Its potentials are vast and it is recommended that you visit the project website to learn more about it.

The post How to install pgAdmin4 on CentOS 8? appeared first on Linux Windows and android Tutorials.

Data is distributed across the drives in one of several ways, referred to as RAID levels, depending on the required level of and performance. The different schemes, or data distribution layouts, are named by the word “RAID” followed by a number, for example, RAID 0 or RAID 1. Each scheme, or RAID level, provides a different balance among the key goals: reliability, availability, performance, and capacity. RAID levels greater than RAID 0 provide protection against unrecoverable sector read errors, as well as against failures of whole physical drives.——[RAID.wikipedia]

The test environment

• CentOS 8.0 virtual machine
• Add two hard disks
• The installation for mdadm

raid-1 operating steps

• Use LSBLK to view the current hard disk partition

lsblk

You can see that sdb and sdc are not in use

• partition for sdb and sdc

Because RAID requires the same size of each hard disk, sdb and sdc are partitioned respectively, and each hard disk is partitioned into a 16G partition, and Hex code is modified as fd

fdisk /dev/sdc

Other hard disk partition process omitted, partition after as follows:

• installation mdadm

yum install madadm

• Create a RAID-1

sdb1, sdc1 form a group of raid-1, RAID device named /dev/md0

mdadm -C /dev/md0 -a yes -l 1 -n 2 /dev/sd{c1,b1}

Check the progress:

cat /proc.mdstat 

View RAID information:

mdadm -D /dev/md0

Here we create a RAID1 disk array from mdadm

• Create the md0 profile

echo DEVICE /dev/sd{b,c}1 >> /etc/mdadm.conf
mdadm -Evs >> /etc/mdadm.con 

• Format & create directory and mount

mkfs.xfs /dev/md0
mkdir    /raid1
mount    /dev/md0 /raid1
df       -h

At this time we can go to /raid1 directory to store our files

• Write the partition table and mount automatically at startup

echo "/dev/md0 /raid1 xfs defaults 0 0" >> /etc/fstab 

Conclusion

Save A file to display of RAID 1, RAID will cut into A1, A2, A3, branch of two pieces of written to disk, can make the disk write speed slightly down, because this way is written to disk, one of the hard disk is broken, another have the same backup hard disk, so the RAID 1 is redundant support, but the cost is quite high, also only 1/2 of the disk space can be used

The post How To Set Up A Software RAID-1 On Centos8 appeared first on Linux Windows and android Tutorials.

CentOS the binary clone of Red Hat Enterprise Linux

It is unlikely that you will not know what CentOS is by now, but I will tell you in a few words. CentOS is a Linux distribution that is built from Red Hat Enterprise Linux binaries. This makes it perfectly compatible with the latter which gives us a robust, reliable and stable system for our home or enterprise servers.

However, there is a small downside, and that is that we will not have the commercial support of RHEL, but it is also completely free to use it. As I said, it makes it ideal for small to medium-sized projects.

The project has been with us for more than 15 years. An age that allows it to distinguish itself as a solid and mature project and has the main objective of providing a free enterprise operating system, easy to use and affordable for everyone.

CentOS 8 based on RHEL 8

As I mentioned, CentOS is a binary level clone of RHEL. Therefore, CentOS 8 is based on RHEL 8. Then, we will be able to have all the news of the Red Hat system in a very easy and simple way.

Some of the new features of RHEL 8 that are also available in CentOS 8 are the following:

• Support for OpenSSL 1.1.1 and TLS 1.3 cryptographic standards.
• Support for Red Hat’s container tool for creating, running, and sharing applications in containers.
• Improved support for ARM and Power architectures, SAP, and real-time applications.

On the other hand, there are other important novelties such as:

• Wayland is the default screen server.
• NTP replaced by Chrony.
• Bloat: IdM (Identity Management Domain), Cockpit.

These are very technical novelties to understand. In general, we will find updates of all kinds such as PHP, Apache, Nginx or Java. Besides Python and the GCC or G++ compilers.

Now all that’s left to do is download it and start working with it. Of course, CentOS 8 will play an important role on our site as usual.

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