Systems & Ops Notes

Field notes from 20+ years across the Linux kernel, DNS, email and SMTP infrastructure, DevOps, SRE, and encryption.

• Creating a New CA (SHA-512, 4096-bit) with PKCS #11 Smart Card Storage and Subordinate CAFebruary 18, 2025

  Create a certificate authority with a 4096-bit RSA key, SHA-512 signatures, PKCS #11 smart card key storage, and a subordinate CA.

• Running PostgreSQL in Docker on my MacApril 13, 2020

  Run PostgreSQL in Docker on macOS, with container setup notes and the original follow-up collection of PostgreSQL commands and examples.

• ElementaryOS: Resolution fix for 2560×1440December 3, 2019

  An Xorg monitor configuration that fixed 2560 by 1440 display resolution on my ElementaryOS installation.

• SendMail function in GolangOctober 28, 2019

  A Go helper for sending HTML and plain-text email over SMTP, with a complete function and usage example.

• Apache 2.4.6 + mod_wsgi + Python 3.6 + Django 2.2.6 on CentOS 7October 14, 2019

  Build mod_wsgi for Python 3.6 and run Django 2.2.6 behind Apache 2.4.6 on CentOS 7, with configuration notes from my setup.

• Nagios environment variablesSeptember 5, 2019

  Pass environment variables to Nagios through systemd using Environment or EnvironmentFile instead of relying on the old sysconfig setup.

• Happy Independence Day!July 4, 2019

  Wishing everybody a wonderful time on this special day in American history. Happy Fourth of July! God bless America!

• Open-Xchange IMAP: STARTTLS failureMay 2, 2019

  Troubleshoot an IMAP STARTTLS failure in Open-Xchange App Suite 7.10.1 by setting explicit SSL protocol and cipher configuration values.

• Paperkey: How to backup your GnuPG keys on paperAugust 13, 2018

  A short field note on exporting GnuPG secret-key material with Paperkey for a printable backup.

• Reset your YubiKey to factory defaults using gpg-connect-agentJuly 6, 2018

  A macOS field note on resetting a YubiKey OpenPGP application to factory defaults with gpg-connect-agent.

• Using YubiKey with GPGJanuary 28, 2018

  My setup notes for using a YubiKey as an OpenPGP smart card to store GPG signing and encryption keys.

• Happy Halloween!October 31, 2017

  Wishing Happy Halloween to everyone!

• Icinga2: LiveStatus Activation/InstallationOctober 30, 2017

  Install and activate the MK Livestatus API for Icinga2, configure its socket, and check that the service is available.

• Icinga2 Director: How to import a server IP from local fileOctober 27, 2017

  Import a server IP address from a local file into Icinga2 Director when the monitoring system cannot reach the DNS server.

• Garage Sale – new or like-new books on Sale!August 1, 2017

  An archived 2017 listing of programming and systems books from my bookshelf, including Python and Ansible titles.

• Quick updateJuly 9, 2016

  A July 2016 update on adding SSL to the website and publishing RPM packages in my personal repository.

• New blog released (english version)June 26, 2016

  The June 2016 introduction to my English-language blog, following my earlier Russian-language website.