Centos-store

Bittorent links can also be obtained from the links above.

Purpose of the article

This article is part of a single series of articles about the Centos server.

Any server administration work begins with the most obvious and mandatory process — installing the necessary OS, which we will do. Download and install CentOS 8 Server in a minimal configuration from a bootable flash drive or over the network to a regular disk or raid partition. Before that, let’s get acquainted with the innovations of the latest version of the distribution and note its main features and differences from the rest.

This article is part of a single series of articles about the Centos server.

Any server administration work begins with the most obvious and mandatory process — installing the necessary OS, which we will do. Download and install CentOS 7 server in a minimal or netinstall configuration from a bootable flash drive or over the network to a regular disk or raid partition. Before that, let’s do a little preparatory work and get acquainted with the details of our distribution, which may be useful in the future.

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A new version of Centos 8 has been released. I recommend using my article on this topic — Installing Centos 8.

Eight months after the release of the Red Hat Enterprise Linux 6.0 distribution, CentOS 6.0, a free variant developed by an independent community based on its package base, is presented. On CentOS, packages from various RHEL repositories, such as server and desktop editions, are combined into a single package repository and distributed as a single installation kit. The distribution is 100% binary compatible with RHEL, the changes made to the packages usually come down to rebranding and replacing the artwork.

When creating CentOS 6.0, a new build system and a new method of checking libraries for full binary compatibility with Red Hat products were used. CentOS 6.0 is available for the i386 and x86_64 platforms as a DVD assembly (4.4 GB) and a reduced network installation image — netinstall.iso (173 MB). The installation CD for servers, as well as LiveCD and LiveDVD are not yet available for download, but will be prepared in the near future.

Separately, it is noted that since RHEL 6.1 has already been released, a continuous update repository will be used for CentOS 6.0, which will allow security fixes released under the RHEL 6.1 branch to be available to CentOS 6.0 without waiting for the release of CentOS 6.1 . The developers plan to provide detailed information about the new method of releasing updates in the next 48 hours. When upgrading from CentOS-4 or CentOS-5 branches, it is recommended to use a full reinstall.

You can get acquainted with the innovations borrowed from RHEL in the announcement — RHEL 6.0

Of the changes made in CentOS 6.0, we can note: Changed the contents of 11 packages: abrt, anaconda, firefox, httpd, kabi-whitelists, luci, openssl098, plymouth, report, xulrunner, yum; Removed 10 packages: abrt-plugin-bugzilla, redhat-release-*, redhat-release-notes*, rhnlib, rhn-check, rhn-client-tools, rhnsd rhn-setup, rhn-setup-gnome, yum-rhn- plugin; Added one package: centos-release.

Known Issues: Text-based installation is automatically activated if the system has less than 652 MB of RAM. The installer requires at least 392 MB of RAM; The capabilities of the text installer are severely limited compared to the functionality of the graphical installer. For example, there is no support for partitioning disk partitions, specifying storage methods, and selecting packages; During installation, on systems with less than 4 GB of RAM, the error «Insufficient memory to configure kdump!» may appear. The problem is solved using the package kexec-tools-2_0_0-153_el6 or newer; The contents of the assembly for the x86_64 architecture did not fit on one DVD, so I had to split the installation image into two parts. The second disk contains only packages from the «Optional» section, ie. in most cases, the first disk should suffice.

Version: 6.0
Platform: i386/x86-x64
Release date: 07/20/2011
Interface language: Multilingual
Developer: The CentOS Project (www.centos.org)
Tablet: Not required
Size: 4.38 GB / 5.1 GB (RAR)
Min. sys. requirements: CPU: 450MHz, RAM: 256MB, HDD: 2.5GB, Video: 8MB

It will also be interesting:

Types of iso images

Only 2 installation images left in CentOS 8:

Using the first one, you can launch the installer and select a mirror on the local network or the Internet to download installation packages. The second allows you to install centos 8 locally, you can not configure the network interface at all.

It is a pity that there is no minimal installation image left for local installation. I usually used this. Netinstall never liked because of the fact that you have to manually write a long url from the repository in order to use it. And just why load the network, if it is more convenient and faster to take a ready-made local iso image. Now there is no such thing. All were transplanted onto a huge DVD image with a volume of around 7 gigabytes.

CentOS 7 installation on raid

Now let’s consider the most difficult installation option. We will install CentOS 7 on software raid. For example, let’s take 2 disks and raid 1. All settings will be the same as we discussed earlier, except for one -.

We connect 2 disks to the system, boot from the installation disk and go to the disk partitioning section. We see 2 hard drives. Select both and check the item I will configure partition:

Press . A slightly crooked hard disk partition management window opens.

Here we first delete all existing partitions:

And create our new ones by pressing the plus sign. We need to create 3 sections: , and root . Choose the partition sizes yourself, based on your needs and RAM on the server. For the boot partition, 500MB is enough, for the swap, the amount of RAM is enough. Everything else can either be filled with one root partition, or create several, if necessary. Set Device Type. Choose the file system type of your choice. Which is better — or depends on the specific situation. It is believed that xfs works better with large files, ext4 with a bunch of small ones. This is a topic for a separate discussion. R AID Level specify

It should look something like this:

Press when finished. In the new window, confirm the partitioning of the disk by clicking Accept Changes:

All other parameters are set as described above. We are now ready to start installing CentOS 7 on the software raid we just created.

During installation, you need to specify a password, or create additional users. I recommend setting a password, users as needed.

After the installation on the raid is completed, we will log into the system and check the state of the array:

#df-h
# cat /proc/mdstat

Let’s look at the information about the root array:

# mdadm -D /dev/md126

Everything is in order, the server installation is finished. The raid section functions normally, providing server fault tolerance.

I highly recommend using mdadm Linux soft raid in your daily activities. It is much more reliable, clearer and more stable than the controllers built into the motherboard. A hardware raid should be preferred only if it is really hardware raid, it has a battery and it really increases the performance of the server. In all other cases, I recommend using mdadm.

I remind you that this article is part of a single series of articles about the Centos server.

Videos

https://youtube.com/watch?v=kYZei59QqMc%3Ffeature%3Doembed

Installing CentOS 8 from a flash drive

The USB flash drive has been prepared, let’s proceed with the installation. We boot from USB and observe the standard, beloved and native (brushed away a tear) Centos installer.

Select the first item: Install Centos Linux 8 and press Enter. After downloading the installer, we are greeted with a window with a choice of language that will be used during installation. I always choose English, it’s more familiar to me. The language of the modern technosphere is English, there’s nothing to be done. I recommend learning if someone is not familiar with it. In the comments to one article where I propose to choose English, a reader told me that I am not a patriot, since I urge you to choose a language other than Russian. I think this is patriotism of the brain. You need to know the enemy by sight 🙂 By the way, no kidding. If you want to surpass someone, first study thoroughly.

Next you will see a slightly updated, but nevertheless familiar interface with installation options. Let’s list them.

An exclamation mark indicates sections that cannot be continued without setting. Let’s go through all the parameters and set the values ​​\u200b\u200bthat we need. So, click on Time & Date (it used to be Date & Time, obviously someone efficient worked and pushed through the change, for which he received a bonus for the quarter) and set the time parameters:

When you’re done, click Done at the top. In the Language Support section, you can select additional languages ​​that the system will support. In principle, there is no great need to configure right now if you do not know for sure whether you will need some other language besides English. All this can be added later. But if you know for sure that you need another language in the system, for example, Russian may be needed if you use Server 1C, then add it right away.

The same with the keyboard. If you need a set in another language, then add it in the Keyboard section.

Next, you need to specify where the installation will be performed from. As I said, in this example I am using the full iso image of dvd1, which allows you to install centos 8 completely locally. I will cover the network installation separately later. So in this case, we don’t need to configure anything separately, by default, the virtual cd-rom is already selected in the form of the sr0 device as a source.

Video of installing CentOS 7 on raid 1

https://youtube.com/watch?v=LoGWPSnjJpM%3Ffeature%3Doembed

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Let’s consider another, more specific installation option. It may be relevant when you are configuring, for example, an iron server to run a KVM hypervisor on it, or a separate Kubernetes cluster node that will use local file storage. We will install CentOS 8 on software raid. For example, let’s take 2 disks and raid 1. All installations will be the same as we discussed earlier, except for one — Installation Destination.

We connect 2 disks to the system, boot from the installation disk and go to the disk partitioning section. We see 2 hard drives. Select both and check Custom.

If there are any partitions on the disks, then delete everything. Further, our task is to perform the same partitioning of the disk as before, only to use mdadm arrays as partitions, which must first be created. It should look like this.

Unfortunately, through the standard installer it will not be possible to install centos 8 not only on mdadm raid 1, but then on lvm partitions on top of mdadm arrays. I did not see such an opportunity. For example, the Debian installation allows you to do this. There are more flexible options for setting up disk layouts and creating partitions.

Then you can start installing centos on a software raid. We will check it after the system boots successfully.

Now let’s check how the server survives the failure of one of the disks. I turned off the server, took out the first disk from which the server booted the first time and set the boot from the second. I turn it on and check.

The server loaded without problems. There were no bootloader errors, except for one moment — the download was significantly longer than usual. Instead of a few seconds, 3-5 minutes. Everything works as it should work out of the box. The standard installer worked correctly, although this is not always the case. Let’s check the state of the array.

# cat /proc/mdstat
# mdadm -D /dev/md126

There is no one disk, but everything works stably. You can schedule a failed disk replacement and add it to the array. True, there may be errors, one of which I recently caught. After the failure of one disk as part of mdadm, the array with the /boot partition for some reason switched to the inactive status and the system did not boot. But I easily fixed it and loaded the server. Details in the article — raid 1 recovery.

I recommend using mdadm soft raid if you don’t have a hardware raid controller. Mdadm is reliable and easy to use. I have never had any serious problems with him and loss of information. Yes, it happens that the server does not boot after a disk failure, there are nuances, but the data always remains intact. Everything can be corrected. It is much more reliable, clearer and more stable than the controllers built into the motherboard. A hardware raid should be preferred only if it is really hardware-based, has a battery, and really increases server performance due to caching. In all other cases, I recommend using mdadm.

Types of CentOS 7 iso images

The release of CentOS contained several types of iso images. A detailed description of each of them is presented in the table:

I usually use either a minimal image or netinstall to install.

CentOS 8 minimal

The next step is to specify which set of software will be installed on the server along with the system. Here you can choose according to your taste and needs. I usually always put the most minimal set, and I add everything that is necessary later. I certainly don’t need a GUI on the server. So my choice is Minimal Install and Standard Install. If I put it on a virtual machine, then I additionally select Guest Agents.

The next important step in installing centos 8 is disk selection and partitioning. There are no universal tips here, it all depends on the purpose of the server and your understanding of the essence of dividing a disk into partitions. Personally, I always choose manual disk partitioning and do it like this:

To switch to manual disk partitioning, you need to select a disk, click Custom and the Done button.

In principle, the /boot partition could also be placed in the root, it will work fine, but I encountered unexpected problems when the /boot partition was on lvm. So I will not recommend you place it there. A size of 1 GB has always been enough for me, but in general, if possible, you can allocate 2 GB, so that there is a noticeable margin.

The installer will automatically offer you to make a swap partition on a separate lvm volume. I usually skip this and don’t swap at all. This is not a fundamental point, it’s just convenient for me. After installation, I include swap as a separate file. This makes them easier to manage. If you don’t want to mess with it, leave it as is. The final layout of the disk is as follows.

After you click Done, a warning will appear.

Warning checking storage configuration. Click for details or press Done again to continue.

You can read the essence of the warning, although I know what will be indicated there. You will be warned that you forgot to create a swap partition. And if you have less than 512 MB of memory on the server, then they will also say that without swap it is impossible to continue the installation with this amount of memory. Then there are no options, connect swap.

I won’t dwell on setting up KDUMP, just disable it. If you do not know what it is, then you 100% do not need it. Let’s take a closer look at configuring network interfaces. We go to the NETWORK & HOST NAME section (it used to be NETWORK & HOSTNAME, without a space, another plus for the quarterly bonus, I think I’m starting to understand the essence of innovations and deprecated announcements in modern systems).

Set the switch to the ON position and automatically get the settings via dhcp if such a service is running on the network that the interface looks at:

We complete the setup by traditional clicking on Done. Now you can return to the clock settings and activate Network Time.

Preparations are essentially completed. Leave the Security Policy section blank. Now you can click on the Begin installation button and run the Centos 8 installation directly. We do this and set the password for the root user in parallel. I like how it is implemented in centos.

CentOS 7 minimal

If you are using the centos minimal iso disk, you will see the following screen:

Here you are prompted to specify installation parameters. An exclamation mark marks a section that cannot be continued without setting it up. The following installation options are available for customization:

To proceed with the installation, at least partitioning of the hard disk is required. Without this, the installation cannot continue. But we will go through all the parameters and set the values ​​\u200b\u200bthat we need.

So, click on DATE & TIME and set the time parameters:

After completing the settings, press the blue button on top.

Go to the next setting — :

Select additional languages ​​that the system will support. Most often, I don’t need this, but for example, let’s add support for the Russian language. This can be useful, for example, when creating a file archive with Russian names in files. With support for the Russian language, you can work in the console with the Russian names of folders and files. If, for example, you have a server configured to act as a gateway, support for additional languages ​​is most likely not useful. Once selected, press again.

Now let’s complete the network settings. We go to the NETWORK & HOSTNAME section. I indicated in detail about setting up network interfaces in one of my articles, so I will not dwell on this issue. Turn the slider to position and automatically get the settings via dhcp:

Finish setting by clicking on . Now you can return to the watch settings and activate.

Now let’s move on to the section. There is no need to change this setting when installing centos minimal. The local source is set there by default, it suits us. You can not touch anything:

In the section with minimal installation, there is also nothing to choose, the only possible option is already indicated:

It remains for us to consider the last mandatory setting, without which the installation of centos will not start — . Having entered it, you will see a list of disks connected to the server. In my case, this is one hard drive.

If your drive is identified correctly, select it and press . A window pops up with a warning that the system will need approximately 1 GB of hard disk space for installation, and your hard disk does not have the required free space. This is because another system was previously installed on this disk and it occupied the entire hard disk. We need to remove all the old information to install the new system. We do this by pressing Reclaim space:

Select a disk and delete all existing partitions on it — first click Delete all, and then Reclaim space:

After that, the installer will select the entire disk as the installation disk. After that, you can start directly installing centos by clicking the Begin Installation button.

Next, consider the option when you install from the netinstall image.

CentOS 7 system requirements

On July 7, 2014, the release of the CentOS 7 distribution was released. Before installing it, it is recommended that you familiarize yourself with the system requirements. You can see the full list of maximum and minimum system requirements in detail on the official wiki. I will give only the most important parameters:

This is the official data from the CentOS website. At RHEL they are the same, I checked. For me personally, everything works safely on VDS and with 512MB of memory, I didn’t try to install less, I think it will start with 256 too.

CentOS 7 netinstall

Installing Centos 7 from the netinstall image differs from the others in only one way. In preparation for installing over a network, in the section, instead of a local source, you need to specify the path to an image located somewhere on the network. Obviously, before doing this, you need to configure the network and make sure that the computer has Internet access.

As a source for installation, I will use the previously mentioned Yandex mirror. CentOS netinstall url — https://mirror.yandex.ru/centos/7/os/x86_64/

The screenshot shows the old url. After a series of updates, it became irrelevant. The correct link is above in the text.

Specify the path and press . After checking the availability of the source, in the SOFTWARE SELECTION section, you can select the software set you need for installation:

Then you can start the installation by specifying all the other parameters that we discussed above.

Bootable flash drive for CentOS 8

Personally, I haven’t used bootable flash drives for anything other than installing a hypervisor in a long time. I try to keep all servers in virtual machines for easy backup and migration. However, if you need a bootable USB stick with CentOS 8, you can easily make it. I think this is relevant for those who put the system on work computers or laptops. True, in this case, my article does not suit you, since it primarily describes the nuances of installing and preparing the system to work on the server. On a work laptop, I prefer to use non-linux.

There are many ways to make a bootable USB flash drive with CentOS 8. If you have a Windows operating system, then I recommend using the free Win32DiskImager program. In the case of linux, you can use Etcher. Although it is available for windows, but it seemed to me a little heavy. disk imager is more convenient in this regard, which is not surprising. After all, Etcher is written in nasty Electron, so it slows down and weighs 80 MB.

True admins can use DD to create bootable flash drives like this:

# dd if=CentOS-8-x86_64-1905-dvd1.iso of=/dev/sdz

I have not personally tested the proposed method, but I see no reason why it might not work.

Support end date

For each release, after the release for 4 years, bug fixes and additions are released, aimed at better performance of hardware and new devices. Also, security fixes are released within 7 years after the release.

For more information on CentOS lifecycle support, take a look at Red Hat’s Errata Policy page.

Download CentOS 7

I prefer to use CentOS Yandex Mirror as such a mirror:

I remind you that there is no 32 bit or i386 edition of CentOS 7. All distributions are x86_64 only, i.e. 64 bit.

Download CentOS 8

You can download CentOS 8 both from the official site and from third-party repositories. I usually use index mirror for download — https://mirror.yandex.ru/centos/ And it’s the same for network installation. So that you don’t have to look for a long time, I’ll say right away that the installation images are here. The structure of the repository is not obvious. For the first time after I got acquainted with centos, I was confused in its repositories, especially when I was looking for a url for netinstall.

I remind you that there is no 32 bit or i386 edition of CentOS 8. All distributions are x86_64 only, i.e. 64 bit.

The following can be used as alternative mirrors to download centos 8:

This is relevant for those who have Yandex blocked for some reason. It is a pity that you have to deal with widespread blocking on the Internet. A bad trend that complicates many things.

Changes in the 8th version

Let’s go through the main innovations of CentOS 8 that seemed interesting. Functionally, this is a complete copy of RHEL 8, so all its changes are 100% relevant for centos. Here is a list of the most interesting changes:

You can find more details about the changes in the 8th version on opennet or read the full list in the original on the redhat website. I skimmed the last one. There in the overview there are links to a detailed description of each component of the system.

Various ISO images

In addition to the main DVD and CD ISO images, the CentOS project releases special ISO images:

Installing CentOS 7 from a flash drive

After creating a bootable flash drive, you can proceed with the installation. We insert the USB flash drive into the server, specify USB as the boot source and start the computer. We are greeted by the initial CentOS installation menu:

Select the first item: Install CentOS 7 and click . After downloading the installer, we are greeted with a window with a choice of language that will be used during installation. I always choose, it’s more familiar to me:

Next, a page is loaded with a choice of basic installation parameters. It will already differ depending on the type of ISO image from which centos is being installed.

Bootable flash drive for CentOS 7

Recently, I personally practically do not use ordinary CDs, preferring bootable flash drives to them. They are more convenient, take up less space, it is easier to update the distribution kit on them. But sometimes you have to get confused to create a bootable USB flash drive. For example, I used to use the unetbootin program to create a bootable USB flash drive for CentOS 6, but this number did not work with the 7th version. The flash drive created in it does not allow installing CentOS 7, since the installer itself at some point does not see the installation source on the flash drive.

But the free program Win32DiskImager came to the rescue. With it, you can easily create a bootable CentOS 7 USB flash drive. Here’s how to do it:

This is enough to create a flash drive. Now you can use it to install the operating system from a USB flash drive.

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New releases

New major and minor releases are available 4 to 6 weeks after the vendor’s (Red Hat) SRPMs (Source Packages). This time is required to build the product from the received code, verify it, test it, translate it, and integrate new features. We understand that many of our users would like to receive new updates early, but we ask you to be patient and help the future release.

CentOS 8 netinstall

Consider now installing centos 8 over the network from a boot image. It is no different from the usual one, except for one thing — you first need to set up a network with Internet access or with access to a local repository and specify this repository as a source for installing the system.

As a source for installation, I will use the previously mentioned Yandex mirror. CentOS 8 netinstall url — https://mirror.yandex.ru/centos/8/BaseOS/x86_64/os/

Specify the path, save the settings and wait for the installer to connect to the repository and take information about the packages from it. After that, in the Software Selection section, you can select the set of software required for installation, as with a local installation. Everything else is configured in the same way as we did above.

CentOS 8 system requirements

There are no fundamental differences in the system requirements of CentOS 8 compared to previous editions. I was able to install and run it on a virtual machine with 1CPU/512Mb. However, there were nuances. Let’s start with the system requirements table.

I tried several times to install Centos 8 on 1CPU/512Mb. With a local installation, everything worked out, although the installer’s graphical interface was decently slow. I did not manage to install on a virtual machine with the same characteristics over the network. I tried several times and each time the installation hung at 44% at the time of downloading packages from a remote repository. As soon as I added memory, the installation proceeded normally. So we can say that the minimum system requirements for installing CentOS 8 over the network are 1 CPU and 1024 MB of RAM. For a local installation, 512 is enough.

I noticed another interesting point that was not in previous versions. If you install a system with 512 MB of RAM and don’t allocate a partition for swap when partitioning the disk, the installer tells you that it needs at least 600 MB of RAM to install without swap.

So keep in mind that if you install CentOS 8 on the minimum system requirements, you will not be able to refuse a separate partition for swap. I usually refuse and include swap as a separate file later. It’s just more convenient that way. Now with 512 MB of memory this will not work. The easiest way is to allocate more memory during installation, and then reduce its amount. Although it will still be necessary to observe how the system will behave with so many resources. On the 7th version of centos, the same nginx in proxy_pass mode works fine with minimal system requirements.

Release Notes

You can get all the original release information for all versions of Red Hat from Red Hat’s Update Release Notes.

Conclusion

This concludes the article on installing a server based on CentOS 8 OS. I recommend doing the basic setup right away. Hope it was interesting and helpful. I tried to consider in detail all the main nuances of the installation, which I myself encounter in the course of my professional activities. The main differences between my articles and similar ones, which are scattered on the Internet is that they are really unique and copyrighted. I always try to bring some of my knowledge and experience gained over the years as a system administrator to the material. Or just express your thoughts.

Before writing the article, I googled both the ru segment and the world segment on the installation of centos 8 and sadly state that I did not find anything interesting. In the top of the issue are banal SEO articles with screenshots and installer steps. Nothing unique or really useful. This is depressing because SEO defeats real practitioners who don’t have time to understand promotion and makes their articles invisible to people because they are not in the top 10 search engine results. If I come across interesting sites with quality content, I bookmark them and browse manually when I have time.

The above problem is relevant for all information sites. I think everyone notices this when they are looking for something on the Internet for non-commercial requests. In the first place is always the SEO of an article with a rewrite of the same garbage. The practical value of such articles tends to zero. Search engines are constantly trying to do something with this, but it doesn’t work out very well, because the SEOs adjust. In this regard, Google works better than Yandex. The latter has a more garbage issue, which is indirectly confirmed by the fact that every year it loses its position as a search engine.

I remind you that this article is part of a single series of articles about the Centos server.