Category: Linux

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Extend root partition – physical storage expand

If you extend the virtual disk that holds the root partition of a linux server, you should extend the physical storage and filesystem in order to allocate the available space. In this article I will explain how to perform the necessary actions to archive this goal.

At first you can see that physical volume is currently 200GB.

In order to extend you should use parted and select the volume which holds the root filesystem. In my case it was number 3 and I performed the extension through the command:

parted -s -a opt devsda 'resizepart 3 100%'

If you check the vg space you may notice that space is not allocated yet.

Then you should perform a pvresize for the aforementioned partition and the space will be provided on the volume group.

pvresize /dev/sda3
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SAP HANA for RedHat 8.4 – Bypass installer compatibility

Red hat provides a playbook that can be used for SAP HANA configuration on RHEL. This ansible script sets environment variables and kernel values in order to optimize the environment for SAP workloads.

https://www.redhat.com/en/blog/getting-started-your-sap-hana-journey-rhel-8-sap-solutions

However you may encounter errors during the installation procedure. This article explains how to bypass them in order to run it on a RHEL 8.4 environment.

The first error you will notice is the sap_domain. This occurs if you have not set a value for this variable on vars.

In order to resolve this issue run the playbook using sap_domain variable.

ansible-playbook site.yml --extra-vars sap_domain=yourdomain

The second issue you will notice is that RHEL 8.4 does not belong to the supported distributions.

The compatibility is stored on the ansible collection vars section and you should edit that. 

vi /usr/share/ansible/roles/sap-hana-preconfigure/vars/RedHat_8.yml

Add 8.3 or 8.4 version and save the file.

The last error you may notice would be about required packages.

Add the below repositories:

subscription-manager repos --enable=rhel-8-for-x86_64-appstream-rpms \
--enable=rhel-8-for-x86_64-baseos-rpms \
--enable=rhel-8-for-x86_64-sap-solutions-rpms \
--enable=ansible-2-for-rhel-8-x86_64-rpms

Rerun the ansible playbook.

Verify the changed states of various tasks and check active tuned profile

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Extend swap size on Redhat – Installer up to 128GB

If you try to allocate more than 128GB on swap partition for a Redhat installation you will notice that is not possible through installer. This is a known bug on Redhat bugzilla that is mentioned as resolved. However I tried to allocate 256GB swap with a RedHat 8.2 installer and I got the maximum size which is 128GB. In this article you will learn how to increase swap size manually.

First validate that there is available space on the volume group. (140g available on my case)

Then extend the swap logical volume

Deactivate swap file

format swap

Reactivate swap partition.

You can verify swap space with 

free -g
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Create and manage users with Ansible – automatically create sudo users

Creating users is a very trivial task that requires time, especially if there is not a Active Directory mechanism integrated with the Linux servers. In order to make your life easier as an administrator you can run the below playbook that will create users based on a list and add them sudo capabilities.

Task 1
creates the users that have been specified on the loop section.

Task 2
creates the appropriate sudoers file

  1 ---               
  2 - name: create sudoers users based on request
  3   hosts: localhost
  4   become: true    
  5   tasks:          
  6     - name: create users based on a list
  7       user:       
  8         name: "{{ item }}"
  9         password: "{{ '#Passw0rd#' | password_hash('sha512') }}"
 10         shell: /bin/bash
 11       loop:       
 12         - user1
 13         - user2
 14                   
 15     - name: create sudoers file for user
 16       copy:       
 17         content: '{{ item }} ALL = (ALL) ALL'
 18         dest: "/etc/sudoers.d/{{item}}"
 19       loop:       
 20         - user1
 21         - user2

Run the playbook and verify that the password is correct and user has sudo capabilities.

ansible-playbook createusers.yml