Centos – F1-CONSULT https://www.f1-consult.com Our Network For Your Network Tue, 27 Apr 2021 08:09:06 +0000 en-US hourly 1 https://wordpress.org/?v=7.1.3 https://www.f1-consult.com/wp-content/uploads/2018/01/cropped-F1-CONSULT-favicon-32x32.png Centos – F1-CONSULT https://www.f1-consult.com 32 32 CentOS – Installer just goes black screen on Centos8 https://www.f1-consult.com/linux/centos-blackscreen/ Thu, 25 Jun 2020 20:38:28 +0000 https://www.f1-consult.com/?p=4609 Problem:

During installation of CentOS the installer screen goes black.

  • The terminal multiplexer is running in virtual console 1.
  • To switch from the graphical installation environment to tmux, press Ctrl+Alt+F1.
  • To go back to the main installation interface which runs in virtual console 6, press Ctrl+Alt+F6.

Available tmux Windows

Shortcut Contents
Ctrl+b 1 Main installation program window. Contains text-based prompts (during text mode installation or if you use VNC Direct Mode), and also some debugging information.
Ctrl+b 2 Interactive shell prompt with root privileges.
Ctrl+b 3 Installation log; displays messages stored in /tmp/anaconda.log.
Ctrl+b 4 Storage log; displays messages related storage devices from kernel and system services, stored in /tmp/storage.log.
Ctrl+b 5 Program log; displays messages from other system utilities, stored in /tmp/program.log.

Switching to Terminal Ctrl+Alt+F1 you see

  • X startup failed, falling back to text mode
  • Pane is dead (signal 10)

Solution:

  • install system with basic video driver
  • install in text mode by adding "inst.text" to the end of the GRUB boot line
  • Press ENTER to continue with the normal boot.
  • Make selection from the above menu. Perform configuration and return back to the main menu by pressing the c key. Once ready begin the RHEL 8 installation by pressing the b key.
]]> CentOS – How do I safely delete old kernel versions ? https://www.f1-consult.com/linux/kernel/ Thu, 13 Sep 2018 23:24:37 +0000 https://www.f1-consult.com/?p=3959 package-cleanup:

Using package-cleanup command which is a part of yum-utils package we can uninstall any number of old kernels automatically. As an example using --oldkernels --count=2 option with package-cleanup command the command will remove all unused kernel while keeping last three most recent kernel versions installed.

package-cleanup --oldkernels --count=1

yum:

list installed kernels

run rpm -q kernel

remove kernels no longer needed; listed above

yum remove kernel

automated:

By default CentOS will keep last 5 kernels installed on your system. This behavior is defined by installonly_limit=5 line within /etc/yum.conf file. Update the /etc/yum.conf configuration file appropriately to keep desired number of old kernels on your system after update. The minimum value to be set is 2.

Example of /etc/yum.conf configuration file to keep only last two kernel versions:

[main]
cachedir=/var/cache/yum/$basearch/$releasever
keepcache=0
debuglevel=2
logfile=/var/log/yum.log
exactarch=1
obsoletes=1
gpgcheck=1
plugins=1
installonly_limit=2
bugtracker_url=http://bugs.centos.org/set_project.php?project_id=23&ref=http://bugs.centos.org/bug_report_page.php?category=yum
distroverpkg=centos-release

read more: linuxconfig.org

]]> ZFS – CENTOS Downgrade https://www.f1-consult.com/linux/storage/zfs/downgrade/ Thu, 13 Sep 2018 23:07:47 +0000 https://www.f1-consult.com/?p=3954 ZFS – Downgrade Commands for Centos:

To do the downgrade/re-install dance:

sudo yum remove zfs zfs-kmod spl spl-kmod libzfs2 libnvpair1 libuutil1 libzpool2 zfs-release
sudo yum install http://download.zfsonlinux.org/epel/zfs-release.el7_6.noarch.rpm

nano /etc/yum.repos.d/zfs.repo
[zfs]
enabled=0

[zfs-kmod]
enabled=1

sudo yum search zfs* --show-duplicates
sudo yum list --showduplicates zfs
sudo yum install kmod-spl-0.7.9-1.el7_5.x86_64 kmod-zfs-0.7.9-1.el7_5.x86_64

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