Category: Docker

Force delete/restart Kubernetes pods

Occasionally, I have a need to delete and restart k8s pods after I’ve been hammering on a cluster, when I need to perform node maintenance, or when a project has run its course and I want to free up the namespace and/or resources. Below is a general overview of that procedure but note that it is specific to certain scenarios only and assumes you know the consequences of your actions. I do not warranty any of this!

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Open up Docker ports in UFW

My home Docker installation had some ports blocked internally for a project I was working on today. The sequence of commands listed below will allow the containers to communicate internally while still keeping open outgoing connection and not changing any incoming UFW rules.

sudo ufw allow in on docker0
sudo sed -i s/DEFAULT_FORWARD_POLICY=\"DROP\"/DEFAULT_FORWARD_POLICY=\"ACCEPT\"/ /etc/default/ufw
sudo ufw enable
sudo iptables -t nat -A POSTROUTING ! -o docker0 -s 172.17.0.0/16 -j MASQUERADE

Original source link: http://blog.lukebennett.com/2015/09/13/make-docker-play-nicely-with-ufw/

Increase swap size for your Raspberry Pi

I have a little low-end POC (proof of concept) I’m testing out at home before I bring it in to work. The POC requires my Raspberry Pi to run a couple of Docker containers which isn’t really a problem. However, I’m using a 1st-gen Pi that came out with only 512MB RAM total. By the time Docker itself was up and running, I had something on the order of 40-50MB of RAM left and another 99MB swap with the stock swap settings. Continue reading “Increase swap size for your Raspberry Pi”

Rancher Kubernetes Engine (RKE) and chicken nuggets

I recently took a position as a cloud engineer with a small startup in the DC area. The startup is big on Kubernetes but we’d struggled to find a suitable framework for deploying fair-to-middlin’ sized clusters quickly on the private clouds we manage. I guess, to clarify: the deployments were completed in a reasonable amount of time, but the automated solutions we tried for initial cluster deployment just weren’t robust enough for daily production use.

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