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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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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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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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rsync commands

Basics

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

Advanced

exclude files/dirs based on patterns

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