Category Archives: Linux

Short Tip: Dealing with FreeBSD for noobs

I had the pleasure to work with FreeBSD again in the past week. I have not touched it in over a year and would consider myself a Linux-only person. I designed a new backup infrastructure which requires a FreeBSD server. … Continue reading

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Short Tip: Install shellcheck on an outdated CentOS

I’ve to install shellcheck on a CentOS 7 box, this is the latest CentOS version. The tool is a great linter for bash scripts, which I want to integrate into our CI pipeline. shellcheck isn’t packaged so I will build … Continue reading

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Short Tip: Installing msgpack on outdated boxes (ruby1.9.1)

I’m using msgpack to serialize the data between my puppet agents and the masters. Recently I had to puppetize an old Debian Wheezy box. I’ve to install msgpack in advance: # gem install msgpack Building native extensions. This could take … Continue reading

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rubocop-rspec magic: Fixing RSpec/InstanceVariable

We recently introduced RSpec/InstanceVariable into our RuboCop configuration at Vox Pupuli. Using instance variables is not considered best practice so we are currently migrating away from them. Here is en example of the old code style: The variables are later … Continue reading

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Create a simple streaming replication for postgres with puppet

I need to build a postgres setup for a important database. The idea is to one master and one-many slaves that can serve read only access. The slaves will work in a hot-standby mode where they continuously receive data from … Continue reading

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Create ssh keys with puppet on a server + pubkey exchange

There are a few solutions to generate ssh keys on a puppet master/server or copy them from hiera to a box. I have got several boxes and every box needs to have ssh access to every other box. I don’t … Continue reading

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Linux Short Tip: systemd-networkd and DNS servers

You maybe have noticed that you can configure DNS servers in your systemd-networkd settings, but these addresses don’t appear in /etc/resolv.conf. You need to enable/start systemd-resolved, this daemon checks global DNS settings in /etc/systemd/resolved.conf, DNS settings for each link from … Continue reading

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Short Tip: Replacing a failed drive in mdadm softwareraid

Sometimes you check your fileserver and your raid looks like this: # cat /proc/mdstat Personalities : [raid1] [raid6] [raid5] [raid4] md125 : active (auto-read-only) raid6 sdl[1] sdh[7] sdf[5] sdk[2] sdg[6] sdm[8] sdi[0] sdn[10] sde[4] 23441080320 blocks super 1.2 level 6, … Continue reading

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Doing IPv6 with systemd-networkd – the correct way

Understanding the docs: I blogged about IPv6 with systemd-networkd in Arch Linux step by step installation guide and provided a hacky workaround to get a working IPv6 address configured. I read through the docs again and hand a longer discussion … Continue reading

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Linux Short Tip: Correct IPv6 with ferm firewalling

I mentioned ferm in my last post about gluster (an iptables/ip6tables abstraction layer in perl with a nice firewall config). The default rule-set looks like this: Most people attend to C&P that blog and wrap it in domain ip6 {} … Continue reading

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