Tag Archives: Ubuntu

Force PKI and Password authentication simultaneously on Ubuntu

I use AD authentication in my environment (for password-based authentication) Current Scenario A valid AD user logs in to the Ubuntu Linux server via SSH That user adds his public key to ~/.ssh/authorized_keys for passwordless login I disable/lock/delete the AD … Continue reading

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Build large environments in no time on Ubuntu using conjure-up

Whether you need to build a Kubernets cluster, an openstack instance, a hadoop cluster…etc, Canonical has developed a tool called conjure-up. This tool can build these whole environments for the purpose of development and testing, or small environments in a … Continue reading

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What to do if docker on Ubuntu doesn’t recognize addition of a user to its group when using PBIS with AD

You add a user to group docker so that you can run docker commands without having to be root or a sudoer. On an Ubuntu 16.04 server which authenticates against AD using PBIS, I added users to group docker, but … Continue reading

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Install docker on multiple Ubuntu Xenial hosts with Ansible

Ansible is an amazing piece of configuration management software. Among its amazing features is that it’s totally agentless and the only 2 packages that it needs on any host are python and an SSH server. Today we will create a … Continue reading

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Fix Slow SFTP/SCP File Upload Rate and Stalling caused by TCP SACK

In brief, sometimes a conflict occurs between some firewalls and the TCP SACK. In my case, the upload was severely affected and reached upload speeds of a few kilobytes over a LAN! The following command disables TCP SACK and fixes … Continue reading

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Securely delete files/folders in Ubuntu

In brief, you should NEVER trust your HDD before handing it over to someone else! The solution to this would be either wipe the whole HDD or at least wipe the files/folders that you need to keep out of reach. … Continue reading

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How to reset lost password on Ubuntu

From the official Ubuntu LostPassword documentation (with minor changes to work on more recent versions of Ubuntu) Reboot your computer. Hold Shift during boot to start GRUB menu. Press e┬áto edit. Find the line starting with “linux” and change “ro” … Continue reading

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