nkhine

Create a dedicated ZFS docker pool with deduplication disabled in case of dedup enabled on your system:

zfs create -o mountpoint=/var/lib/docker -o dedup=off rpool/docker

Sometimes, you don't want ZFS for docker storage. ZFS can be sadly quite painful with Docker in Docker and similar scenarios. It might be best to avoid the problem by creating a volume in your ZFS pool, formatting that volume to ext4, and having docker use "overlay2" on top of that, instead of "zfs".

zfs create -s -V 30G rpool/docker

mkfs.ext4 /dev/zvol/rpool/docker

nkhine

<#
- BIOS of host machine also needs to be configured to allow hardware virtualization
- This gist WSLv2, but can use WSLv1 instead. I needed v1 as I run Windows 10 in a VM in Virtualbox.
- WSLv2 has been giving me problems in Virtualbox 6.1, but WSLv1 works properly.
- vbox has issues with the GUI settings when it comes to nested virtualization on certain systems,
  so run the following if needing to give a VM this enabled setting:

  VBoxManage modifyvm <vm-name> --nested-hw-virt on
#>

nkhine

#! /bin/sh
### BEGIN INIT INFO
# Provides: vpnclient
# Required-Start: $all
# Required-Stop: $network $local_fs $remote_fs $syslog
# Default-Start: 2 3 4 5
# Default-Stop: 0 1 6
# Short-Description: Start VPN Client at boot time
# chkconfig: 345 44 56
# description: Start VPN Client at boot time.

nkhine

Kubectl output options

Let's look at some basic kubectl output options.

Our intention is to list nodes (with their AWS InstanceId) and Pods (sorted by node).

We can start with:

kubectl get no

nkhine

jobs

jenkins_url + /api/json?tree=jobs[name,color]

builds

jenkins_url + /job/${job_name}/api/json?tree=builds[number,status,timestamp,id,result]

last build

nkhine

### No longer needed as of nginx-1.13.9-1.el7_4.ngx.x86_64.rpm from nginx.org
### it was compiled against OpenSSL 1.0.2 from CentoOS 7.4 so it supports ALPN (HTTP2 works)
### nginx-module-njs-1.13.9.0.1.15-1.el7_4.ngx.x86_64.rpm

yum -y groupinstall 'Development Tools'
yum -y install wget openssl-devel libxml2-devel libxslt-devel gd-devel perl-ExtUtils-Embed GeoIP-devel rpmdevtools

OPENSSL="openssl-1.0.2l"
NGINX_VERSION="1.13.9-1"
NJS_VERSION="1.13.9.0.1.15-1"

nkhine

AWS CLI Cheatsheet

http://docs.aws.amazon.com/IAM/latest/UserGuide/best-practices.html https://www.youtube.com/watch?v=_wiGpBQGCjU

Setup

nkhine

AWSTemplateFormatVersion: '2010-09-09'
Description: Cognito Stack
Parameters:
  AuthName:
    Type: String
    Description: Unique Auth Name for Cognito Resources

Resources:

  # Creates a role that allows Cognito to send SNS messages

nkhine

$ sudo -i
# vim /etc/systemd/system/disable-transparent-huge-pages.service
# systemctl enable disable-transparent-huge-pages
# systemctl start disable-transparent-huge-pages
# systemctl status disable-transparent-huge-pages
# cat /sys/kernel/mm/transparent_hugepage/enabled
# cat /sys/kernel/mm/transparent_hugepage/defrag

nkhine

# WARNING - THIS IN NOT a SHELL SCRIPT - JUST a LIST of COMMANDS
# based on https://github.com/coreos/coreos-overlay/issues/595 with links updated

# Build cifs-utils in a container and copy it into /tmp on the host.
$docker run -t -i -v /tmp:/host_tmp fedora /bin/bash
# On the container bash prompt
yum groupinstall -y "Development Tools" "Development Libraries"
yum install -y tar
yum install -y bzip2
curl http://ftp.samba.org/pub/linux-cifs/cifs-utils/cifs-utils-6.3.tar.bz2 | bunzip2 -c - | tar -xvf -