Through this article I’m delighted to introduce a new category on the Ceph blog called User Story. The aim of this category is to offer general feedback to centralized users . The structure of the article is as follows:
Since you have the whole gist of the article, let’s start!
After several months, we have an important update for the argonaut v0.48.x series. This release contains a critical fix that can prevent data loss or corruption in a power loss or kernel panic situation. There are also several fixes for the OSDs and for the radosgw. We recommend all v0.48.x users upgrade.
Notes on upgrading:
Notable changes since v0.48.2:
We found a few critical problems with v0.56, and fixed a few outstanding problems. v0.56.1 is ready, and we’re pretty pleased with it!
There are two critical fixes in this update: a fix for possible data loss or corruption if power is lost, and a protocol compatibility problem that was introduced in v0.56 (between v0.56 and any other version of ceph).
This release will kick off the bobtail backport series, and will get a shiny new URL for it’s home.
We’re bringing in the new year with a new release, v0.56, which will form the basis of the next stable series “bobtail.” There is little in the way of new functionality since v0.55, as we’ve been focusing primarily on stability, performance, and upgradability from the previous argonaut stable series (v0.48.x). If you are a current argonaut user, you can either upgrade now, or watch the Inktank blog for the bobtail announcement after some additional testing has been completed. If you are a v0.55 or v0.55.1 user, we recommend upgrading now.
Notable changes since v0.55 include:
We always love it when Ceph users choose to share what they have been doing with the community. Recently, a couple of regulars to the #ceph IRC channel were good enough to give us a very detailed look at how they were using Ceph to power their VMWare infrastructure. So, without further ado, read on for a great visual representation and quick summary of Chris Holcombe and Robert Blair’s pet Ceph project!
War. War never changes. Some of you may have been following my bitter rivalry with Mark Shuttleworth. Now, I am perfectly aware that I share nearly as much blame as he does for this entire debacle. We”ve both done things that can”t be undone and we”re just going to have get past it. (Come on Slashdot? flamebait? You really need an incredibly obvious click-baiting descriptor.) Anyway, I think it”s time to finally bury the hatchet. Let bygones be bygones and all that? I say we all sit down, calmly work through our differences, and find peace in mutual… Oh who am I kidding. The only way to resolve this is through a fight to the death!
Oh no, not me and Shuttleworth. I wouldn”t stand a chance. I”ve heard rumors that Unity can now plant subliminal messages in your dreams. How am I supposed to fight when I can”t even sleep? No this must be resolved through aquatic lifeform combat. Can the champion Argonaut defend his title from the likes of the upstart challenger Bobtail? Will competitive fighting arcade games from the early 90s make a come back? Will Protendo and Kobatashi ever be able to reclaim their lost honor? Let the battle commence!
It’s been a few months since the last named release, Argonaut, and we’ve been busy! Well, in retrospect, most of the time was spent on finding a cephalopod name that starts with “b”, but once we got that done, we still had a few weeks left to devote to technical improvements. In particular, the OSD has seen some new and interesting developments.
Let’s start with some background for those not familiar with ceph internals. Objects in a Ceph Object Store are placed into pools, each of which is comprised of some number of placement groups (PGs). An object “foo” in pool “bar” would be mapped onto a set of osds as follows:
There were some packaging and init script issues with v0.55, so a small point release is out. It fixes a few odds and ends:
You can get this release from the usual locations:
We have seen users deploying Ceph in a number of different ways, which is just plain awesome! I have spoken with people deploying with makecephfs, ceph-deploy, Juju, Chef, and even the beginnings of some Puppet work. However, thanks to collaboration between Inktank and Dell there is a really solid deployment pathway using Dell’s Crowbar tool and a Ceph “barclamp.”
For those not familiar with Dell Crowbar, it is an Open Source cloud deployment framework that originated as a way for Dell to support their OpenStack and Hadoop powered solutions. Since its inception, and eventual open source-ing at OSCON 2011, it has come a long way, growing into the full-featured solution that we see today. Crowbar uses packages called “barclamps” that allow individuals to create ready-made ways to deploy the tools they want (like Chef’s “recipes” or Juju’s “charms”). These barclamps include custom UI for config, dependency graphs, and even localization support. Using it as one of the powerful devops vehicles to deploy Ceph seemed like the next logical step.
Ok, so you have gone through the five minute quickstart guide, learned a bit about Ceph, and stood a pre-production server up to test real data and operations…now what? Over the past couple of weeks we have gotten quite a few questions about monitoring and troubleshooting a Ceph cluster once you have one. Thankfully, our doc has been getting a ton of polish. However, we figured a quick rundown of some of the more frequently-useful troubleshooting tools might be helpful.
The first step to fixing a problem is understanding that you actually _have_ a problem in the first place. To that end there are a number of health and monitoring tools available to keep a hairy eyeball on Ceph. These tools can be run in interactive mode (just typing ‘ceph’ from the command line) or by a series of status queries and watch commands. To run the ceph tool in interactive mode, type ceph at the command line with no arguments. For example: