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watch -n -5 kubectl get events --all-namespaces=true --field-selector type=Warning

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echo ATTENTION: THIS IS UNSAFE!

echo Which namespace would you like me to terminate\?

read NAMESPACE_TO_DESTROY

echo I will terminate namespace $NAMESPACE_TO_DESTROY\!
(
    kubectl proxy &
    kubectl get namespace $NAMESPACE_TO_DESTROY -o json |jq '.spec = {"finalizers":[]}' >temp.json

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rsync commands

Basics

rsync -avzh <source> <username>@<ip>:<destination>

Advanced

exclude files/dirs based on patterns

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redirect traffic incoming on a specific port to a different IP address / another server

2.2.2.2:4000 -> 1.1.1.1:3000

Solution

iptables -t nat -A PREROUTING -p tcp --dport 4000 -j DNAT --to-destination 1.1.1.1:3000
iptables -t nat -A POSTROUTING -p tcp -d 2.2.2.2 --dport 4000 -j SNAT --to-source 1.1.1.1
iptables -t nat -A POSTROUTING -j MASQUERADE

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iptables cheatsheet

Show iptables rules

This will show the now current state of iptables

iptables -S

This will show all current iptable rules

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[manual] create ceph filesystem

Configure MDS (MetaData Server) on a Node which you'd like to set MDS. It sets to [node01] on this exmaple.

ceph-deploy mds create node01

Create at least 2 RADOS pools on MDS Node and activate MetaData Server. For pg_num which is specified at the end of a creating command, refer to official document and decide appropriate value. Documentation

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#!/bin/bash

# insert/update hosts entry
ip_address="192.168.x.x"
host_name="my.hostname.example.com"
# find existing instances in the host file and save the line numbers
matches_in_hosts="$(grep -n $host_name /etc/hosts | cut -f1 -d:)"
host_entry="${ip_address} ${host_name}"

echo "Please enter your password if requested."

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[troubleshooting] macOS M1 minikube network issue

When starting minikube, we see a docker network related error.

Issue

$ minikube start
😄  minikube v1.24.0 auf Darwin 12.0.1 (arm64)
✨  Automatically selected the docker driver

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[manual] ceph client setup

Cheatsheet for setting up a new ceph client

Gather key and config

From any autheticated ceph host/client.

root@ceph:~$ ceph auth get-or-create client.fs

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[manual] create erasure-coding ceph filesystem pool

Cheatsheet how to setup a erasure coding pool, add it to a ceph filesystem and configure files/directories to use the ec pool.

root@ceph:~$ ceph osd erasure-code-profile set ec-62-profile k=6 m=2 crush-failure-domain=osd crush-device-class=hdd
root@ceph:~$ ceph osd pool create glacier_data_ec-62 erasure ec-62-profile
root@ceph:~$ ceph osd pool set glacier_data_ec-62 allow_ec_overwrites true
root@ceph:~$ ceph osd pool application enable glacier_data_ec-62 cephfs
root@ceph:~$ ceph fs add_data_pool glacier glacier_data_ec-62