Category: Linux

Articles related to all distros of Linux.

Ansible for VMware

Although Ansible is typically used to execute tasks on multiple machines concurrently by generating Python scripts from YAML files and copying over those scripts to the remote machines for execution, it can also be used to execute tasks for remote endpoints on the local machine by executing the “Python-from-YAML” scripts locally. This use-case is typical
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HOW-TO: Install Graylog on a single server

Here’s a no-frills rundown of the procedure that I followed to install the Graylog 2.5 Log management application on a RHEL 7.6 VM with outbound connectivity (tcp/443) to the internet: STEP 1: Install Java and Utilities sudo yum install java-1.8.0-openjdk-headless.x86_64 epel-release sudo yum install pwgensudo yum install java-1.8.0-openjdk-headless.x86_64 epel-release sudo yum install pwgen STEP 2: Install
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Consistent Network Device Naming in RHEL 7

Traditionally, Linux OSes named network interfaces in the format ethN (e.g. eth0, eth1, etc.). This assignment did not establish any relationship between the interface name and its location on the server. Hence, on a multihomed server, the OS might swap interface names (e.g. eth0 becomes eth1 and vice versa) upon reboot depending on how the
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Failed to obtain ICMP socket: Operation not permitted

When executing a program (check_icmp) as part of the Check_MK software, the following error was displayed: check_icmp: Failed to obtain ICMP socket: Operation not permitted The “check_icmp” program had the following “ls -l” listing: -rwsr-x---. 1 root omd 4874 Aug  7  2018 check_icmp Note the 4750 octal value for the file’s permissions above. The check_icmp
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RHN registration Introspect error

Problem: When trying to register a Linux client with an RHN Satellite server using the rhnreg_ks utility, the following error is displayed: Introspect error: The name com.redhat.SubscriptionManager was not provided by any .service files   Background & Analysis: The Linux client was on RHEL 5.8 The rhnreg_ks is a utility used to register a Linux
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Sendmail is slow

Problem: The sendmail service takes a while (more than a minute) to start and emails sent via sendmail take a couple of minutes to get delivered:   Background & Analysis: Sendmail uses DNS for the following: At startup, to obtain the canonical name for the local host. To obtain the canonical name of a remote
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Linux LVM Example

Requirement: Wipe away /old and add the space recovered (5 GB) to /new for the following disk layout: Filesystem Size Used Avail Use% Mounted on /dev/mapper/VG01-LV01_app 5G 2.5G 2.5G 50% /old /dev/mapper/VG02-LV02_app 5G 2.5G 2.5G 50% /new /old is mounted on Logical Volume LV01 in Volume Group VG01 Volume VG01 comprises 1 Logical Volume /dev/mapper/VG01-LV01_app
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Unknown groups in SLES

Problem: On SLES 11 SP 1, while trying to add users with the useradd command, the following is displayed: useradd: Unknown group `video’. useradd: Unknown group `dialout’. Background & Analysis: The “video” and “dialout” groups are default groups in SLES. This is configured in /etc/default/useradd. These groups were removed from /etc/group using the groupadd command
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How to Install PHP with FreeTDS on Linux

There are PHP applications which use MSSQL as the back-end database and such applications require FreeTDS to enable PHP code interface with MSSQL. This article describes how to install PHP and FreeTDS on Linux hosts. To compile or not?: Typically, it is recommended to use package managers like yum to install software on Linux platforms.
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Unable to load module osad

Problem: The osad service does not start (RHEL 5.7) and throws the following error: Starting osad: Unable to load module osad Background & Analysis: The osad service is required on all Red Hat Network Satellite clients to receive pushed actions from the RHN Satellite Server. For more details on the osad and related services, please
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