Karan Singh

Code Never Lies, Comments Sometime Do !!

Effectively Monitoring a Ceph Cluster

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Effectively Monitoring a Ceph cluster

Hello guys, during my system house keeping i found this video , which i had recorded some time ago, thought to share with you.

This video is about how we do monitoring of our Production Ceph clusters. In our company we prefer open source software for service monitoring. We have been using the following open source projects all-together for monitoring.

  • Opsview : Its based on Nagios. Until March 4 , 2015 OpsView was available under GPL license , however its opensource version is now discontinued.
  • Collectd : collectd gathers statistics about the system it is running on and stores this information
  • Graphite : Is a tool for monitoring and graphing the performance of computer system in real time.
  • Grafana : Is Graph and dashboard builder for visualising time series data

Opsview Monitoring for Ceph cluster

Live Demo : OpenStack and Ceph

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openstack and ceph live demonstration

Hey Guys , with this blog post i would like to share live demonstration screen cast that i have prepared using my openstack and Ceph environment.

What’s expected from this Demo

  • Creating OpenStack glance image stored on Ceph RBD
  • Creating OpenStack instance with Ephermal disk on Ceph RBD ( storing instance on Ceph )
  • Creating OpenStack Cinder volume on Ceph RBD
    • Attaching this volume to OpenStack instance
    • Mounting this volume and generating some load
  • OpenStack Instance LIVE MIGRATION across hypervisors

Un-installing OpenStack RDO

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Uninstalling OpenStack

RedHat Distribution of OpenStack ( RDO ) is one of the most popular openstack distribution for test, dev and production environments. Deploying OpenStack infrastructure using RDO is fairly easy.

However there is no automated uninstall process for RDO (or OpenStack in general).

With the help of this blog I will share my secret sauce that I personally use to uninstall / remove openstack from my development & test environments. This saves me from reinstalling the entire OS and over the OS configurations + it saves time.

Calamari Packages for Community

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Ceph Calamari Packages for Community

Recently I have been playing around Ceph calamari, which is a management and monitoring system for Ceph storage cluster. It provides a beautiful Dashboard User Interface that makes Ceph cluster monitoring amazingly simple and handy.

Deploying OpenStack KILO Using RDO

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Deploying OpenStack KILO using RDO

Getting openstack up and running using RDO is fairly straight forward. However many people have asked to deploy openstack with an existing external network. This method should allow any machine on the network to be able to access launched instances via their floating IPs.


  • CentOS7
  • OpenStack RDO KILO
  • Vagrant ( Optional )

Docker Containers in Just 10 Commands

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Docker container in 10 commands

If you are on this page, then you definately know what is Docker , i will not take your time with the introduction part.

Lets do Docker !!!

  • Install docker packages on your Linux host , in my case its CentOS.
# yum install -y docker-io

Ceph: Monitor Troubleshooting

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Ceph monitor ip change

While playing with your Ceph cluster , you might have seen HEALTH_WARN cluster status.

Cluster warning can occur due to several reasons of component malfunctioning such as MON,OSD,PG & MDS.

In my case i saw warning due to Ceph monitors, which was like :

health HEALTH_WARN 1 mons down, quorum 0,1 ceph-mon1,ceph-mon2

Ceph : Reduce OSD Scrub Priority

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Ceph : Reduce OSD Scrub Priority Let’s assume ! on a nice sunny day , you receives complaints that your Ceph storage cluster is not performing as it was performing yesterday. After checking cluster status you found that placement groups scrubbing is going on and depending on your scenario , you would like to decrease its priority. Here is how you can do it.

Ceph Loves Jumbo Frames

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Ceph Loves Jumbo Frames Who doesn’t loves a high performing Ceph storage cluster. To get this you need to tame it , i mean not only Ceph tuning but also Network needs to be tuned. The quickest way to tune your network is to enable Jumbo Frames.

What are they :

  • They are ethernet frames with payload more than 1500 MTU
  • Can significantly improve network performance by making data transmission efficient.
  • Requires Gigabit ethernet
  • Most of the enterprise network device supports Jumbo Frames
  • Some people also call them ‘Giants’