Author: kittycool only

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Sorting ls Output Based on Time and Date

You may want to list the files in a directory based on last modified time and date from the latest to the oldest, you will need to use -t 

% ls -lt
drwxr-xr-x  26 root root    4096 Mar 29 13:40 mono
drwxr-xr-x   2 root root      42 Mar 29 13:40 mono-source-libs
lrwxrwxrwx   1 root root      22 Dec 21 12:55 libnss_centrifyda.so.0 -> libnss_centrifyda.so.2
drwxr-xr-x.  2 root root      62 Dec 21 12:54 security
lrwxrwxrwx   1 root root      22 Dec 21 12:54 libnss_centrifydc.so.0 -> libnss_centrifydc.so.2
lrwxrwxrwx   1 root root      28 Dec 21 12:54 libnss_centrify_logonly.so.0 -> libnss_centrify_logonly.so.2
-rwxr-xr-x   1 root root  238560 Nov 17 09:13 libnss_centrifydc.so.2
-rwxr-xr-x   1 root root  140064 Nov 17 09:13 libnss_centrify_logonly.so.2
-rwxr-xr-x   1 root root  159112 Nov  9 02:39 libnss_centrifyda.so.2
drwxr-xr-x   4 root root      40 Jul 25  2021 fastx
drwxr-xr-x.  2 root root     100 Dec 11  2020 modprobe.d
drwxr-xr-x   8 root root     180 Oct 26  2020 rstudio-server
.....
.....

If you want a sorting from the oldest to the latest, you use the -r option

% ls -ltr
.....
.....
-rwxr-xr-x   1 root root  159112 Nov  9 02:39 libnss_centrifyda.so.2
-rwxr-xr-x   1 root root  140064 Nov 17 09:13 libnss_centrify_logonly.so.2
-rwxr-xr-x   1 root root  238560 Nov 17 09:13 libnss_centrifydc.so.2
lrwxrwxrwx   1 root root      28 Dec 21 12:54 libnss_centrify_logonly.so.0 -> libnss_centrify_logonly.so.2
lrwxrwxrwx   1 root root      22 Dec 21 12:54 libnss_centrifydc.so.0 -> libnss_centrifydc.so.2
drwxr-xr-x.  2 root root      62 Dec 21 12:54 security
lrwxrwxrwx   1 root root      22 Dec 21 12:55 libnss_centrifyda.so.0 -> libnss_centrifyda.so.2
drwxr-xr-x   2 root root      42 Mar 29 13:40 mono-source-libs
drwxr-xr-x  26 root root    4096 Mar 29 13:40 mono
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Learn to Accelerate TensorFlow on Intel® Architecture with Minimal Code Changes

The OpenVINO™ integration with TensorFlow enables you to speed up the TensorFlow workflow by adding just two lines of code. Enhance performance on Intel platforms while using the familiar TensorFlow APIs. Download this whitepaper to get started.

Do sign up and get the white papers Learn to Accelerate TensorFlow on Intel® Architecture with Minimal Code Changes

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Calculate Data Centre Cooling Requirements

The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) develops and publishes thermal and humidity guidelines for data centers. The latest edition outlines the temperatures and humidity levels at which you can reliably operate a data center based on the equipment classification.
……
…..
In the most recent guidelines, ASHRAE recommends that IT equipment be used with the following:
– Temperatures between 18 and 27 degrees C or 64 and 81 degrees F;
– dew point -9 degrees C to 15 degrees C; and
– relative humidity of 60%

How to calculate data center cooling requirements

General calculation you can start with to get a baseline British thermal unit (BTU) cooling size:
(Room square footage x 20) + (IT equipment watt usage x 3.14) + (Active people in the room x 400)

To Convert BTU/hour in watts, multiply by 0.293
To Convert Watts into BTU/hour, multiply by 3.41
To Convert Tons into watts, multiply by 3530
To convert Watts into Tons, multiply by 0.000283

How to calculate data center cooling requirements

For more information, do take a look at How to calculate data center cooling requirements

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Delinea announces support for AlmaLinux and Rocky Linux

Finally, Delinea (Centrify) has added support for RHCOS, AlmaLinux x86_64, Rocky Linux. Good news indeed

As we continue to bolster our PAM solutions for Linux, the latest release of Server Suite adds support for RHCOS, AlmaLinux x86_64, and Rocky Linux.

Red Hat Enterprise Linux CoreOS (RHCOS) is a container-optimized operating system for running containers at scale. Both Rocky Linux and AlmaLinux are binary-compatible with Red Hat Enterprise Linux (RHEL) and have emerged as a viable alternative to CentOS.

………

Delinea announces support for AlmaLinux and Rocky Linux
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Installing Nvidia Drivers on Rocky Linux 8.5

If you are planning to install Nvidia Drivers on Rocky Linux 8.5, you may want to use DNF to install. For a detailed explanation Streamlining NVIDIA Driver Deployment on RHEL 8 with Modularity Streams

Step 1: Add Offical Nvidia Repository to Package Managers repository list. 

# dnf config-manager --add-repo=https://developer.download.nvidia.com/compute/cuda/repos/rhel8/x86_64/cuda-rhel8.repo

Step 2: Install Kernel-Devel and Headers used by the Drivers

# dnf install kernel-devel-$(uname -r) kernel-headers-$(uname -r)

Step 3: Installing Nvidia Drivers and Settings

# dnf install nvidia-driver nvidia-settings

Step 4: Install CUDA Drivers and REboot

# dnf install cuda-driver

Once done, do a reboot,

# reboot

If after a reboot and if you do a “nvidia-smi” and receive an error like the one

# nvidia-smi
NVIDIA-SMI has failed because it couldn't communicate with the NVIDIA driver. Make sure that the latest NVIDIA driver is installed and running.

You may want to take a look at https://gist.github.com/espoirMur/65cec3d67e0a96e270860c9c276ab9fa. It could be coming Secure Boot Option in your BIOS.

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“This system is not registered to Red Hat Insights” after log in to Rocky Linux 8.5

If you have warning messages such as after your login to your

This system is not registered to Red Hat Insights. See https://cloud.redhat.com/
To register this system, run: insights-client --register

To remove the warning permanently, you can do a 

# dnf remove insights-client

References:

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Installing MLNX_OFED 5.5-1 on Rocky Linux 8.5

If you are installing MLNX-OFED-5.5-1 on Rocky Linux 8.5, you may want to download the drivers from Nvidia Linux Drivers

Step 1: Installing Prerequistics

# dnf install tk tcsh tcl gcc-gfortran kernel-modules-extra

Step 2a: Installing MLNX on Rocky 8.5

If you just do a ./mlnxofedinstall 

# ./mlnxofedinstall
Current operation system is not supported!

Step 2b: Force Install with the right distro.

# ./mlnxofedinstall --distro rhel8.5 --force
.....
.....
.....
Device #1:
----------

  Device Type:      ConnectX5
  Part Number:      MCX512F-ACH_Ax_Bx
  Description:      ConnectX-5 EN network interface card; with host management 25GbE Dual-port SFP28; PCIe3.0 x16; ROHS
  PSID:             MT_0000000416
  PCI Device Name:  10:00.0
  Base GUID:        xxxxxxxxxxxx
  Base MAC:         yyyyyyyyyyyy
  Versions:         Current        Available
     FW             16.31.1014     16.32.1010
     PXE            3.6.0403       3.6.0502
     UEFI           14.24.0013     14.25.0017

  Status:           Update required

After installing…….

Restart needed for updates to take effect.
Log File: /tmp/PAl8Z5mkHc
Real log file: /tmp/MLNX_OFED_LINUX.150443.logs/fw_update.log
To load the new driver, run:
/etc/init.d/openibd restart

Step 3: You have to remove and reload the drivers before you can do the /etc/init.d/openibd restart

[root@h00 media]# modprobe -rv ib_isert rpcrdma ib_srpt
rmmod ib_isert
rmmod iscsi_target_mod
rmmod rpcrdma
rmmod ib_srpt
[root@h00 media]# /etc/init.d/openibd restart
Unloading HCA driver:                                      [  OK  ]
Loading HCA driver and Access Layer:                       [  OK  ]

References:

  1. Driver Installation of Mellanox InfiniBand
  2. Mellanox NIC driver: Current Operation System is not supported
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Disable the web console message from Cockpit on Rocky Linux 8.5

When you logged on to Rocky Linux 8.5, you may see this message. 

Activate the web console with: systemctl enable --now cockpit.socket

This system is not registered to Red Hat Insights. See https://cloud.redhat.com/
To register this system, run: insights-client --register

If you wish to disable the message, you may want to 

rm -f /etc/motd.d/cockpit

The command will remove the symlink to file /run/cockpit/motd

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Setting up NTP Client in Rocky Linux 8.5

Prerequisites Step 1: Endure you are in the correct time zone

# timedatectl
               Local time: Wed 2022-04-20 10:04:44 +08
           Universal time: Wed 2022-04-20 02:04:44 UTC
                 RTC time: Wed 2022-04-20 02:04:44
                Time zone: Asia/Singapore (+08, +0800)
System clock synchronized: no
              NTP service: active
          RTC in local TZ: no

Prerequisites Step 2: List Time Zone

# timedatectl list-timezones
.....
Asia/Singapore
.....

Prerequisites Step 3: Set Time Zone

# timedatectl set-timezone Asia/Singapore

In Rocky Linux 8.5, the ntp package is no longer supported and it is implemented by the chronyd (a daemon that runs in user-space) which is provided in the chrony package.

chrony works both as an NTP server and as an NTP client, which is used to synchronize the system clock with NTP servers.

To install the chrony suite, use the DNF Package Manager.

# dnf install chrony

Enable the Service

# systemctl start chronyd
# systemctl status chronyd
# systemctl enable chronyd

Check it is synchronised 

[root@h00 etc]# timedatectl
               Local time: Wed 2022-04-20 10:19:56 +08
           Universal time: Wed 2022-04-20 02:19:56 UTC
                 RTC time: Wed 2022-04-20 02:19:56
                Time zone: Asia/Singapore (+08, +0800)
System clock synchronized: yes
              NTP service: active
          RTC in local TZ: no

Setting up NTP Client Using Chrony in Rocky Linux 8.5

# vim /etc/chrony.conf
.....
pool sg.pool.ntp.org iburst
.....
# systemctl restart chronyd

Show the current time sources that chronyd is accessing

# chronyc sources
MS Name/IP address         Stratum Poll Reach LastRx Last sample
===============================================================================
^? 178.128.223.142               0   6     0     -     +0ns[   +0ns] +/-    0ns
.....
.....
.....

References:

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Comparison between the /etc/os-release of RHEL-8.5 and Rocky Linux 8.5

Rocky Linux is a production-ready downstream version of Red Hat Enterprise Linux started by original founder of CentOS, Gregory Kurtzer. the OS is almost identical under intensive development by the community.

For RHEL-8.5, 

NAME="Red Hat Enterprise Linux"
VERSION="8.5 (Green Obsidian)"
ID="rhel"
ID_LIKE=”fedora"
VERSION_ID=”8.5"
PLATFORM_ID="platform:el8"
PRETTY_NAME="Red Hat Enterprise Linux 8.5 (Green Obsidian)"
ANSI_COLOR="0;31"
CPE_NAME=”cpe:/o:redhat:enterprise_linux:8.5:GA”
HOME_URL=”https://www.redhat.com/”
DOCUMENTATION_URL=”https://access.redhat.com/documentation/red_hat_enterprise_linux/8/”
BUG_REPORT_URL=”https://bugzilla.redhat.com/”

For Rocky-Linux-8.5,

NAME="Rocky Linux"
VERSION="8.5 (Green Obsidian)"
ID="rocky"
ID_LIKE="rhel centos fedora"
VERSION_ID="8.5"
PLATFORM_ID="platform:el8"
PRETTY_NAME="Rocky Linux 8.5 (Green Obsidian)"
ANSI_COLOR="0;32"
CPE_NAME="cpe:/o:rocky:rocky:8.5:GA"
HOME_URL="https://rockylinux.org/"
BUG_REPORT_URL="https://bugs.rockylinux.org/"
ROCKY_SUPPORT_PRODUCT="Rocky Linux"
ROCKY_SUPPORT_PRODUCT_VERSION="8"