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Computing KVM/QEMU Linux Proxmox VE

Reflections on Proxmox VE

I’ve now been using Proxmox VE as a hypervisor in my home lab for a couple of years, and as I’ve reverted to plain Ubuntu Server + KVM, I figured I would try to summarize my thoughts on the product. Proxmox VE can be described as a low-cost and open-source alternative to VMware vSphere with […]

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Computing HowTo Linux Postfix

Email address tags in Postfix and Dovecot

What if you could tag the mail address you provide when registering for various services to simplify the management of the inevitable stream of unsolicited mail that follows? If you could register myname+theservicename@mydomain.tld it would make it very easy to recognize mail from that service – and it would make it easy to pinpoint common […]

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Computing HowTo IPv6 KVM/QEMU Linux

IPv6 guests in KVM

I’ve been experimenting with IPv6 at home, and spent some time trying to get it working in my virtual machines. The first symptom I got was that VMs got a “Network unreachable” error when trying to ping6 anything but their own address. The cause was a complete brainfart on my side: We need a loopback interface […]

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Computing HowTo Linux

Frustrations in Ubuntu 18.04

My first frustration with Ubuntu 18.04 came yesterday. I created a template VM with my basic toolkit that any machine in my network should have. I then deployed the VM and asked vSphere to set the hostname to the value of the VM name. Strangely, this didn’t happen: The new machine booted up alright, but […]

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Computing HowTo Linux

Transport security with Postfix

I had a “Face: Meet Palm” moment today, and as usual when that happens, I learned something new: What happened was that I noticed that mail from a Postfix server I use for sending mail from a couple of domains was marked with the red “no encryption” label rather than the expected grey “standard encryption” […]

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Computing HowTo Linux

Resizing the system volume on a Linux VM

Background With LVM, the preferred way of adding storage space to a computer running a Linux-based operating system seems to be to add disks, judging by my search results. Naturally, this is a great way of minimizing disruption in a physical machine, but what if you’re running your machines virtually? Adding virtual disks tends to […]

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Ansible Computing Git Linux

Test whether a git pull is needed from within a batch script

Just a quick hack I did to avoid having to sync a couple of scripts unnecessarily when deploying my load balancers. Underlying idea stolen from a post by Neil Mayhew on Stackoverflow. Shell session script: #!/bin/bash UPSTREAM=${1:-‘@{u}’} LOCAL=$(git rev-parse @) REMOTE=$(git rev-parse “$UPSTREAM”) BASE=$(git merge-base @ “$UPSTREAM”) if [ $LOCAL = $REMOTE ]; then GIT_STATUS=nochange […]

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Ansible Computing Git HAProxy HowTo Linux

Environment variables for services in a systemd-based system

My current config deployment automation project has required me to set up a dev/staging environment for my load balancers, since I don’t want to break stuff by deploying untested configurations. This environment is functionally identical to a single load balancer and can be used along with a hosts file on a client to not only […]

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Ansible Computing Git HAProxy HowTo Linux Web Services

Continuous Deployment of Load Balancer Configurations

I thought I’d describe some optimizations I’ve made to my load balancers at work, both for the good of the older me, and in case someone would benefit from some of my ideas. Background The load balancers are based on four software packages that integrate to create a powerful whole: Keepalive Daemon provides a common […]

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Computing Exchange 2016 HAProxy Linux Windows

Load Balancing Exchange 2016 behind HAProxy

I recently started the upgrade to Exchange 2016 at work. A huge benefit over Exchange 2010, is that REST based client connections are truly stateless. In effect this means that if a server goes down, clients shouldn’t really notice any issues as long as something redirects them to a working server. In my system, this […]