https://www.neilborromeo.com/categories/linux-systems/ Recent content in Linux Systems on Neil Borromeo - I build dependable infrastructure, automation, and digital systems for real-world businesses Hugo en-us Sun, 15 Mar 2026 05:02:00 +0800 https://www.neilborromeo.com/blog/2026/03-15-improving-send-only-smtp-deliverability-with-spf-and-dkim/ Sun, 15 Mar 2026 05:02:00 +0800 https://www.neilborromeo.com/blog/2026/03-15-improving-send-only-smtp-deliverability-with-spf-and-dkim/ A practical send-only mail setup using Postfix, SPF, and OpenDKIM to improve deliverability. https://www.neilborromeo.com/blog/2025/01-23-installing-terraform-on-ubuntu-24-04-lts/ Thu, 23 Jan 2025 00:00:00 +0800 https://www.neilborromeo.com/blog/2025/01-23-installing-terraform-on-ubuntu-24-04-lts/ A short reference note for installing Terraform from HashiCorp's apt repository on Ubuntu 24.04. https://www.neilborromeo.com/blog/2024/09-24-certbot-renewal-with-a-docker-compose-nginx-reload-hook/ Tue, 24 Sep 2024 00:00:00 +0800 https://www.neilborromeo.com/blog/2024/09-24-certbot-renewal-with-a-docker-compose-nginx-reload-hook/ A short practical note on renewing Let's Encrypt certificates with Certbot and reloading Nginx inside a Docker Compose stack. https://www.neilborromeo.com/blog/2024/05-27-upgrading-gitlab-from-16-10-to-17-0-without-skipping-the-required-step/ Mon, 27 May 2024 00:00:00 +0800 https://www.neilborromeo.com/blog/2024/05-27-upgrading-gitlab-from-16-10-to-17-0-without-skipping-the-required-step/ A practical GitLab upgrade note showing the required stop at 16.11 before moving from 16.10 to 17.0. https://www.neilborromeo.com/blog/2024/03-22-working-around-a-payment-api-cors-problem-with-a-server-side-proxy/ Fri, 22 Mar 2024 00:00:00 +0800 https://www.neilborromeo.com/blog/2024/03-22-working-around-a-payment-api-cors-problem-with-a-server-side-proxy/ A short troubleshooting note on why browser-side payment API calls can fail on CORS and why a proxy is often the safer fix. https://www.neilborromeo.com/blog/2024/03-06-wiping-or-formatting-a-usb-disk-from-wsl-2/ Wed, 06 Mar 2024 00:00:00 +0800 https://www.neilborromeo.com/blog/2024/03-06-wiping-or-formatting-a-usb-disk-from-wsl-2/ A practical note on identifying, attaching, wiping, and detaching a physical disk through WSL 2. https://www.neilborromeo.com/blog/2024/02-29-fixing-a-cloudflared-tunnel-by-reauthenticating-and-recreating-credentials/ Thu, 29 Feb 2024 00:00:00 +0800 https://www.neilborromeo.com/blog/2024/02-29-fixing-a-cloudflared-tunnel-by-reauthenticating-and-recreating-credentials/ A practical note on repairing a cloudflared setup by upgrading the binary, logging in again, and recreating tunnel credentials. https://www.neilborromeo.com/blog/2024/02-23-fixing-thumbor-ssl-renewal-on-an-aging-certbot-install/ Fri, 23 Feb 2024 00:00:00 +0800 https://www.neilborromeo.com/blog/2024/02-23-fixing-thumbor-ssl-renewal-on-an-aging-certbot-install/ A note on diagnosing SSL renewal problems on an older host that was still using `certbot-auto`. https://www.neilborromeo.com/blog/2024/02-15-restarting-a-vault-container-in-a-staging-environment/ Thu, 15 Feb 2024 00:00:00 +0800 https://www.neilborromeo.com/blog/2024/02-15-restarting-a-vault-container-in-a-staging-environment/ A short operational note on restarting and inspecting a Vault container inside a Compose-based staging environment. https://www.neilborromeo.com/blog/2024/02-09-compacting-a-wsl-2-ext4-vhdx-disk/ Fri, 09 Feb 2024 00:00:00 +0800 https://www.neilborromeo.com/blog/2024/02-09-compacting-a-wsl-2-ext4-vhdx-disk/ A short note on shrinking the virtual disk file used by a WSL 2 distribution. https://www.neilborromeo.com/blog/2023/11-30-installing-an-ssh-entry-point-for-wsl-2-on-windows-10/ Thu, 30 Nov 2023 00:00:00 +0800 https://www.neilborromeo.com/blog/2023/11-30-installing-an-ssh-entry-point-for-wsl-2-on-windows-10/ A practical note on exposing a WSL 2 SSH service through Windows port proxy rules. https://www.neilborromeo.com/blog/2023/10-05-forcing-ipv4-and-disabling-ipv6-on-ubuntu-20-04/ Thu, 05 Oct 2023 00:00:00 +0800 https://www.neilborromeo.com/blog/2023/10-05-forcing-ipv4-and-disabling-ipv6-on-ubuntu-20-04/ A short note on disabling IPv6 at the sysctl layer on Ubuntu 20.04. https://www.neilborromeo.com/blog/2023/09-28-fixing-br-netfilter-sysctl-errors-during-kubernetes-node-prep/ Thu, 28 Sep 2023 00:00:00 +0800 https://www.neilborromeo.com/blog/2023/09-28-fixing-br-netfilter-sysctl-errors-during-kubernetes-node-prep/ A quick fix for Kubernetes node setup failures caused by missing bridge netfilter kernel support. https://www.neilborromeo.com/blog/2023/07-03-fixing-a-deepops-or-openshift-ansible-run-blocked-by-pkg-resources/ Mon, 03 Jul 2023 00:00:00 +0800 https://www.neilborromeo.com/blog/2023/07-03-fixing-a-deepops-or-openshift-ansible-run-blocked-by-pkg-resources/ A short troubleshooting note for Ansible runs that fail because Python cannot import `pkg_resources`. https://www.neilborromeo.com/blog/2021/04-05-provisioning-a-centos-7-instance-on-vultr/ Mon, 05 Apr 2021 22:50:00 +0800 https://www.neilborromeo.com/blog/2021/04-05-provisioning-a-centos-7-instance-on-vultr/ A cleaned-up 2021 work log for bringing up a CentOS 7 server on Vultr with MariaDB, Nginx, PHP-FPM, Varnish, and Let's Encrypt.