RHEL

Install and Configure NTP server for time adjustment in RHEL/Centos

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### Install NTPd. [root@testos ~]# yum -y install ntp ### Edit/Update NTP Configuration file [root@testos ~]# vi /etc/ntp.conf ### line 18: add the network range you allow to receive requests restrict 10.0.0.0 mask 255.255.255.0 nomodify notrap ### change servers for synchronization ### change servers for synchronization #server 0.centos.pool.ntp.org iburst #server 1.centos.pool.ntp.org iburst #server 2.centos.pool.ntp.org iburst … Read more

Convert the dmesg timestamps to human-readable format on Linux

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The dmesg results from newer Linux kernels show the timestamps. the dmesg timestamp is the time in seconds since the kernel starting time. [root@unixonline]# dmesg [2593404.865599] vmxnet3 0000:0b:00.0 ens192: intr type 3, mode 0, 5 vectors allocated [2593404.868590] vmxnet3 0000:0b:00.0 ens192: NIC Link is Up 10000 Mbps [2593426.220166] vmxnet3 0000:0b:00.0 ens192: intr type 3, mode … Read more

MySQL Server Time Zone Support

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This article describes the time zone settings maintained by MySQL, how to load the system tables required for named time support, how to stay current with time zone changes, and how to enable leap-second support. Beginning with MySQL 8.0, time zone offsets are also supported for inserted datetime values; see “The DATE, DATETIME, and TIMESTAMP Types”, … Read more

Generate Random Password in Linux and Solaris CLI (pwgen)

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According to pwgen man page, “the pwgen program generates passwords which are designed to be easily memorized by humans, while being as secure as possible.” It returns multiple password options that meet the criteria you provide so that you can select the one that you prefer. ### Install pwgen On RHEL/CentOS Linux, you can install … Read more

Is it safe to set net.ifnames=0 in RHEL7, RHEL8 and RHEL9?

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Issue: Is it safe to disable Consistent Device Naming by setting net.ifnames=0 on the kernel command line in RHEL7, RHEL8 and RHEL9? Why can I no longer use the 70-persistent-net.rules file to force persistent ethX names like I could in earlier versions of Red Hat Enterprise Linux? Resolution: No. Red Hat strongly recommend that the … Read more

HP Smart Storage Admin CLI (ssacli) installation on Linux

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Why use HP Smart Storage Admin CLI? You can use ssacli (smart storage administrator command line interface) tool to manage any of supported HP Smart Array Controllers in your host without need to reboot your server to access Smart Storage Administrator in BIOS. That means no host downtime when managing your storage. CLI is not as convenient as GUI … Read more

Splunk Enterprise 9.x license activation for test cases on Linux

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Splunk Enterprise is a data platform designed to help businesses manage big data and analyze machine data. It can be deployed on-premises or in the cloud via the Splunk Cloud Platform and enables you to search, analyze and visualize your data to quickly act on insights from across your technology landscape. An Enterprise Splunk License … Read more

Install Splunk Enterprise 9.0 on RHEL/CentOS 8

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Splunk Enterprise is a data platform designed to help businesses manage big data and analyze machine data. It can be deployed on-premises or in the cloud via the Splunk Cloud Platform and enables you to search, analyze and visualize your data to quickly act on insights from across your technology landscape. Installing/Starting Splunk Enterprise 9.0.4 … Read more

vsftpd terminated after buffer overflow detected in Linux

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Issue : When run the “ftp open” command, vsftpd terminated after buffer overflow detected printed. [root@unixonline ~]# ftp localhost Connected to localhost.localdomain. *** buffer overflow detected ***: /usr/sbin/vsftpd terminated ======= Backtrace: ========= /lib64/libc.so.6(__chk_fail+0x2f)[0x2b43730d0c5f] KERBEROS_V4 rejected as an authentication type Or “lftp” command “ls” is returned “Delaying before reconnect”. [root@unixonline ~]# lftp test@192.168.10.10:~> ls `ls’ at … Read more

How to Recover Removed File in Linux

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In this scenario, we are going to recover removed file in Linux OS.for example: /data/mongodb/audit/sh0-prm-audit.log is removed. Find the deleted file by lsof command: [root@unixonline]# lsof | grep -i delete init 1 root 9r REG 253,7 10406312 528590 /var/lib/sss/mc/initgroups (deleted) hald 2706 haldaemon 19r REG 253,7 10406312 528593 /var/lib/sss/mc/initgroups (deleted) ntpd 2874 ntp 4r REG … Read more