linux

Using a 'quasi'-disposable VM for UpdateVM in Qubes

In Qubes, the dom0 is updated via an 'UpdateVM' which is responsible for downloading any new packages (since dom0 has no direct network access of its own).

Typically the UpdateVM is your sys-firewall or any other VM you've chosen (it's configurable under Global Settings via the Qubes Manager, or with qubes-prefs from command-line).

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Migrating a Vagrant VM into Qubes as StandaloneVM

I had a Vagrant VM on my other laptop that I wanted to convert into a Qubes AppVM (StandaloneVM).

The disk was lazy allocated 40GB but only using about 1.3GB within the guest.

The underlying disk of the Vagrant VM was a .vmdk. A lot of guides online talk about compacting VDIs, but I had to convert my VMDK first, I couldn't compact it directly.

Here's how I got it into Qubes.

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Source based load-balancing in HAproxy based on X-Forwarded-For header

We had some application servers behind an active/passive HAproxy loadbalancer pair (using keepalived to arbitrate the IP on failover).

We needed to put a WAF product in front of the HAproxy pair (e.g Sucuri's CloudProxy or CloudFlare). This might seem odd to put a reverse proxy in front of a HAproxy pair (yo dawg, I heard you like proxies), but we need to do some funky extra munging of URLs and the like via HAproxy configuration rules, which upstream providers can't account for.

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Yubikey 2FA on Qubes redux - adding a backup key

Previously I wrote about adding Yubikey 2FA authentication in Qubes (not for using Yubikey on remote sites, but on 2FA of your Qubes system itself), explaining a couple of the differences in my technique compared to the official docs (e.g I don't believe in backdooring with a password in absence of your Yubikey, especially since with a usbVM, that VM can read the password as you type it!

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Batch updating TemplateVMs in Qubes 3.0

If you are a Qubes user like me, you probably have a number of TemplateVMs which your App/USB/ProxyVMs are based off of (e.g, you aren't using the same template for all VMs, as you would otherwise develop a fair bit of irrelevant bloat across them all).

If so, you've probably discovered that keeping all those templates up to date with security updates is rather cumbersome when doing so manually.

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Yubikey in Challenge Response mode with Qubes

EDIT: this is still worth/necessary reading, but see an April 2016 update where I describe further improvements, including supporting a backup key in case you've lost your first.

I bought a new Yubikey for use with Qubes, but I had some issues with the challenge-response instructions in the documentation.

That is:

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Using Ansible and Jenkins to check for stale inodes

As part of teaching myself Ansible this week, I've been porting some of my sysadmin toolset into playbooks. I thought I'd share one today that I call 'Stale service check'.

Anyone in operations who does patching on a routine basis knows that a simple 'apt-get upgrade' is rarely enough to apply a security update; Linux uses linked libraries, and frequently when a library is updated, many services that depend on that library are not yet using the new version. OpenSSL is a classic example (remember why you had to 'reboot' to fully clear the Heartbleed vulnerability?)

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'So, what is it you exactly do?' - Part five, troubleshooting

In the last article of this sysadmin series, I talked about the importance of monitoring as an insight into infrastructure and application behaviour - something that is hard to overstate. But what good is monitoring if you don't understand what it's telling you? That's where troubleshooting comes in.

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