mikejoh

Setting up a Docker container as a DHCP server

In this guide I’ve tested a number of different commands and configurations using Docker to run a container with dhcpd (+macvlan driver) to serve my clients in my home network. In the end i’ll migrate from my Windows 2012 R2 Server running DHCP to a much more lightweight Docker container (7.42 MB in total). Wow.

My home environment:

• Firewall (Juniper)
  • I’m running IP helper for bootp which in this case means that i relay DHCP requests from various VLANs into one where i've placed my Windows 2012 R2 server. This is also where my container will live. See the FW configuration below:

mikejoh

Learning Kubernetes

I'm running this on Mac OSX 10+!

Pre-req:

• VirtualBox (there are other alternatives)
• kubectl
• minikube
• jq

mikejoh

git config file

1. Add the below to the following file ~/.gitconfig

[user]
        name = <your name>
        email = <your email address>
[color]
        ui = auto
[alias]
 st = status

mikejoh

tmux

Tested on Mac OSX High Sierra 10.13+ with iTerm2

Install tpm plugin manager

git clone https://github.com/tmux-plugins/tpm ~/.tmux/plugins/tpm

and add the following in the end of your ~/.tmux.conf, uncomment any plugins that you wont be using:

run '~/.tmux/plugins/tpm/tpm'

mikejoh

Jenkins Groovy good-to-have snippets

Example of printing all properties of an object

import java.lang.System
import hudson.model.*
import jenkins.model.*
import com.cloudbees.jenkins.plugins.bitbucket.endpoints.*

mikejoh

Certified Kubernetes Administrator

Clusters

Cluster	Members	CNI	Description
k8s	1 etcd, 1 master, 2 worker	flannel
hk8s	1 etcd, 1 master, 2 worker	calico
bk8s	1 etcd, 1 master, 1 worker	flannel
wk8s	1 etcd, 1 master, 2 worker	flannel

mikejoh

gcloud one-liners

Fetch all Pod (labled backend) logs with severity error from StackDriver (parsing with jq)

gcloud logging read "resource.labels.pod_id:backend AND severity:ERROR" --order asc --format json | jq '.[].textPayload'

Stop all instances

gcloud compute instances stop $(gcloud compute instances list | grep -v "NAME" | awk '{ print $1}')

mikejoh

Quick start guide setting up a small k8s cluster in GCE

Notes

• We'll be running Ubuntu 18.04 instances
• On Ubuntu 18.04 and Kubeadm 1.11.1 you can experience problems with nodes not

Step-by-step

1. Create one master node and one worker node. Warning for wall of script below:

mikejoh

tmux one-liners

To enter command mode in tmux do: Prefix + :

Set background color in current pane (command mode)

select-pane -P 'bg=red'

Synchronize commands across panes (command mode)

mikejoh

Docker one-liners

Get a shell in a container (e.g. when failing)

docker run -ti --entrypoint /bin/bash IMAGE_NAME