Costin Stefan

Welcome to my blog. You will find here random stuff, mostly IT infra-related.

How to restore a Kubernetes cluster after IP change

Recently I had to fix a kubernetes cluster which had its IP addresses changed. The team that changed the IP address on the machines also replaced the hostname in /etc/hosts. However, this is not enough. In order to restore the cluster, you also have to change the IP address in kubernetes cluster manifest files. [[email protected] ~]# cat /etc/hosts 127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4 ::1 localhost localhost.localdomain localhost6 localhost6.localdomain6 11.11.112.42 k8s-master 11....

January 18, 2023 · 2 min · 256 words · costin

New year, new changes

After a period on which I focused more on work, I’ve decided I need to change a bit the blog. 9 months ago I’ve migrated my blog from DigitalOcean to Github Pages. DigitalOcean was great for me when I started my first droplet, but I wanted to experiment with other technologies. So I’ve migrated my blog to Github Pages and my email to Apple Mail. But since I work a lot with CI/CD pipelines at work, I wanted to create an automated pipeline for my blog....

January 14, 2023 · 1 min · 162 words · costin

How to change NTP server on HP 3PAR 7200c

Recently I had to add more NTP servers to a HP 3PAR 7200c storage. Here’s how I did it: 3PAR_hostname cli% setnet ntp -add 10.90.221.13 NTP server successfully updated. Show current NTP server(s): 3PAR_hostname cli% shownet IP Address Netmask/PrefixLen Nodes Active Speed Duplex AutoNeg Status 10.23.155.8 255.255.255.192 01 1 1000 Full Yes Active Default route : 10.23.155.1 NTP server : {} 10.102.102.132 10.102.102.133 10.90.221.13 DNS server : None Remove one NTP server:...

September 19, 2020 · 1 min · 190 words · costin

How to bypass Chrome error "Your connection is not private"

If you’re an IT professional that has to deal with old systems that have self-signed certificates you most probably had to add exceptions to your browser many times. Maybe even import those self-signed certificates locally. Unfortunately when you’re working on a customer’s jump host this is not an option. And starting with more recent version of Chrome this is not possible anymore, you don’t have the option to Add it as an exception....

June 30, 2020 · 1 min · 149 words · costin

How to quickly enable a low-resource webserver

Have you ever wanted to just start a Webserver in a second, for a quick and dirty task but didn’t want to install a full LAMP/LEMP stack? This is possible with the help of a python module and here it is in action: [email protected]:~$ mkdir testare [email protected]:~$ cd testare/ [email protected]:~/testare$ echo MERGE! > index.html [email protected]:~/testare$ pushd $PWD; python3 -m http.server; popd ~/testare ~/testare Serving HTTP on 0.0.0.0 port 8000 (http://0.0.0.0:8000/) ....

April 29, 2020 · 1 min · 145 words · costin