I did not take the course RH436 that prepares to the certification, so I guess that anyone can do it that way too. What do you need to pass this certification ? As usual with Red Hat, this certificate of expertise is based on hands-on tasks to realize, so there is no way to get this certification by just thinking you know about the technology. This presentation from Thomas Cameron, a Red Hatter, at the Red Hat Summit 2011 is a good start to get to know the technology. If you can do everything he does during the presentation, you are on a good way to get the certification
Of course, a virtual environment is a good idea, for example to create multiple networks (such as application, cluster heartbeat, storage1 and storage2) that way you can train on multipathing with iSCSI targets.
Finally, in order to train on Red Hat Storage, downloading the packages from the community website might not be a too bad idea, as the community version of Gluster is not too different from the enterprise version used in Red Hat Storage (although that might change in the future).
All in all, this certification was not too difficult, although I still learned a lot by training for it ! Next certificate of expertise in sight : the EX442 Red Hat Enterprise Performance Tuning Expertise which is, from what I heard from my colleagues, much more challenging. I am looking forward to taking that one !
As I am on vacation with some time to kill, I decided to free my Samsung Galaxy SII from all the Samsung crapware and install an open-source version (GPLv2 and Apache 2 licenses) of Android on it : CyanogenMod. Here is how I did it, using Fedora 17 only.
I do not take any responsibility for what you do with your device. YMMV with your Android version and hardware model. This kind of operations voids the warranty of your smartphone and may damage it irreversibly. (But, hey, it’s fun )
First, let’s compile and install the tool that will help us to root our Android mobile phone “Heimdall”. We start by installing the development tools and needed libraries.
$ tar -xvf recovery-clockwork-184.108.40.206-galaxys2.tar
The extracted file is a kernel image called “zImage” that we will boot on later on
Put the CyanogenMod as well as the GoogleApps in the root directory of your SD card, then, let’s get rid of the Samsungoid ! This is also the right moment to backup your data and configuration, in case anything goes wrong.
Power off the Samsung Galaxy S II and connect the microUSB to the computer but not to the Samsung Galaxy S II.
Boot the Samsung Galaxy S II into download mode by holding down Home & Volume Down & Power while connecting the microUSB to it.
Change the directory back to where the previously extracted zImage file is and execute the following command
# heimdall flash –kernel zImage
A blue transfer bar will appear on the phone showing the kernel being transferred. But, unlike CyanogenMod’s documentation mentionned, my Galaxy SII did not reboot automatically. I tried to boot it by pressing on the power button on the right side, but it did not work. The only thing that worked was starting the phone by pressing on Home & Volume Up & Power at the same time, until the ClockworkMod Recovery booted.
In ClockworkMod Recovery, select the following options
“Wipe data/factory reset” then “Wipe cache partition”
“Install zip from sdcard” -> “Choose zip from sdcard” and choose first CyanogenMod and redo the operation for the Google Apps zip file
Once the installation has finished, select “Go Back” to get back to the main menu, and select “Reboot system now” and CyanogenMod should boot as it did for me.
So far, the user experience is much better and my phone is way faster than it used to be. The process was not as straightforward as I described it here and I had a couple of “interesting” moments when the Galaxy did not boot as expected, but I hope it will make your switch to a freer operating system smoother.
When starting at Red Hat as a solution architect, one of the things on is expected to do is become Red Hat Certified Engineer.
This certification happens in two steps. The first exam is the Red Hat Certified System Administrator (RHCSA) exam, and the second is the actual RHCE exam. You need to pass both successfully to become a RHCE. Although I was a RHCSA for a couple of weeks now already, I failed at my first attempt (as do 60% of all participants !) at the RHCE, and only last week did I get my RHCE.
This certification is made of a couple of hands-on tasks. Unlike the LPI, which is a multiple-choice questionnaire and where luck can play a role, you actually need to really know how things work with the RHCE,which makes it so interesting and challenging.
Now that I am a RHCE (which can be verified) I will continue with other courses, next one will be the Red Hat Enterprise Virtualization class to become RHCVA (Red Hat Certified Virtualization Administrator). You can see below the entire curriculum that leads to the ultimate title, the Red Hat Certified Architect (RHCA)
Update : I get my RHCVA last week. Again, it was a hands-on exam with standard tasks for administrators (i.e. setup a complete virtualization environment with management server, hypervisor, etc.). My next goal is the EX436, clustering and storage management !
This video of the founder of the Linux kernel is fascinating. I am pretty sure that the world will stumble upon the one shocking phrase that Linus said during this conference at the Aalto University, in Finland : “F*** you Nvidia”.
Linus is obviously an opinionated person and this sentence was tweeted, re-tweeted and shared all around the world. But it misses all the other points Linus made during this presentation; to me, this presentation was an excellent leadership lesson in 7 points:
1) You don’t have to plan something to be successful at it
When Linus started his operating system, he was “looking at a new project to use [his] computer”. Today, according to Google, 900 000 Linux-based Android devices are activated. How more successful could an “accidental” project be ?
However, I think that even though Linus had no exact plan about what his OS would become, several factors helped him along the way. He stated, for instance that “when [he] started Linux, [he] had been programming half of his life”. He was not a complete beginner. He had time to create and shape something entirely new, as he was a student. Linus mentioned that the “development of Linux was very natural.”. I think that this development was natural because the external factors were positive at that time. You don’t have to make big plans for something to be successful, but watch your environment if, even without planning, you want to be successful.
2) Focus on your strength
According to Linus, the strength of open-source is that people can do what they are best at. It helped him focus and not have to bother about minor tasks. He put his passion, interest and energy where they were the most effective: the development of an operating system kernel.
3) Trust is limited, put it in people who deserve it
Although people might have thousands of LinkedIn contacts, for instance, they really trust only a handful of them. In Linus’ case, it is between 5 and 15 people and only 3 to 4 can really take his job over. It is not that many, they have to be the right ones.
4) You have the right to be opinionated
Linus is honest in his statements, he uses strong language and if people are offended “it’s their problem”. The story with Nvidia is, again, a blatant example of it. However, if the media only remembers this three-words sentence, it might forget the five-minutes explanation that preceded it. Torvalds explained in a lot of detail what went wrong with this company and why he was displeased. His wording might be offensive, he has very valid reasons to be angry, though.
Moreover, these opinions are important as a leader. As Linus said “people take him seriously [...] and in an open-source community, other developers need to know how he feels”. He explains very well in this interview how, in the past, not to have taken a decision early enough leaded to trouble subsequently. As a leader, people should not misread you and you should take decisions as early as possible to show where the way is going.
5) Give credit to others
I found remarkable that Linus gave credit to others. He did it in particular to Dennis Ritchie and Brian Kernighan, two of the inventors in the 70s of Unix, which leaded the way to Linux in the 90s. Leadership, to me, is about showing to the world what you have done, if it makes an impact, but also recognizing when you sit on the shoulders of giants.
6) Work hard and execute
For Linus, “execution is more important than vision”. He believes in hard work and attention to detail and in Edison’s definition of genius : 90% of perspiration – 10% of inspiration. This is what made him successful.
I found his sentence very inspiring “If you look at the stars all the time, you’ll stumble upon the pothole in the garden”.
7) Do it with passion
During the last minutes of the conference, Linus said “I believe that having passion, caring about what you do is more important than having this mental vision of a golden future you want to reach”. As a leader, people should do everything they do with passion. In my opinion, it is a trait of leaders that they really care about the things they are doing and that passion is a driving force for their efforts.
The free-market capitalistic definition of companies’ goals was, for a long time, very simple: to make as much profit as possible. With that in mind, the only difference between a success and a failure was the investor’s return on investment. Short-term profit became priority number one. However, this classic definition of capitalism has transformed the way companies are perceived in the population over time.
Businesses are now considered to be prospering at the expense of the communities. Although people buy from companies, they are not entities people want to trust. Firms are perceived as being obsessed with financial results and having a detrimental effect on their surrounding environment.
TV series, which are an expression of popular culture, are an interesting example of this change. As a child, I used to watch TVseries, such as Knight Rider or Airwolf, where private companies or foundations helped fight organized crime and bring justice. Looking at TV series of today, the contrast is striking. Prison Break and Heroes both staged corporations as their villains. Funnily, all these firms are called “The Company,” making them even more impersonal. In their respective shows, these companies are instigators of conspiracies and use treason, murder, and crime to reach their objectives. The criminals are just executing the master plans of the board of directors while the heroes fight them for justice.
This expression of the popular culture demonstrates the current perception of companies in communities: ruthless managers will do whatever it takes to optimize short-term financial results at the expense of the rest of the world.
Companies, under customer or regulatory pressure, try to correct this image through periodic social actions. However, creating shared value (for both society and corporations) should not be put at the margin of the business model, but at the core. The business model should be to do good, and make money out of it, rather than make money…and do good if time and resources permit.
An interesting example to me was the quarterly earnings calls of a tech company I have invested in. The top managers spoke for an hour and a half about financial results, goals and business initiatives, until the VP of corporate responsibility had a meagre fifteen-minute time slot to present all charitable actions undertaken by the company. These actions are laudable. Nonetheless, it really gave me the feeling that making profit while doing something good for communities was an indirect result through the product and services sold, but was not at the core of this company’s business.
This vision of doing good first and making money out of it may seem like a post-capitalist utopia, driven by top managers lacking social recognition. However, this model already exists and already generates billions of dollars. Some companies’ business units already work according to these principles, but more importantly, many firms are completely focused on creating shared value.
Free software businesses are a great example of creating this shared value. Companies like Red Hat, Talend, or Pentaho embody the principles of shared value by making billions of US dollars of revenue and supporting communities worldwide. Distributing software under, for instance, the General Public License, these businesses charge neither companies nor consumers for the use of their products, but rather for support, consulting, and services. Moreover, they provide the source code (the instructions that make the programs work) for study or modification. The comparison to a proprietary approach is fascinating: instead of selling a license, free software providers sell a solution.
They don’t sell a product; they sell value.
Beyond the sole scope of corporations, free software creates shared value by directly serving disadvantaged communities, providing incredibly advanced technology to lower-income homes. The beauty of free and open source software (FOSS) is that it can be distributed at no charge. Anyone can install and use a zero-cost operating system and applications, provided by company-sponsored initiatives, such as Fedora or Ubuntu. The open source licenses make it very easy to adapt the products to the needs of users, reusing components already developed by other projects. The GPL, for instance, allows the use of GPL-licensed software for any purpose. Unlike proprietary software, which is bound to countless usage limitations, free and open source software fosters the usage of technology by giving the freedom of use to the end users. Of course, hardware is still needed at some point in time, but open source software can be equally used by people in developed as well as in developing countries, thus providing cutting-edge technology (such as virtualization) at virtually no cost.
Free software companies support the development of free and open source software projects. Their creation, such as the way the Linux kernel is written, is a collaborative approach. Anyone can participate and send patches to correct bugs in the program or launch the development of a brand-new module. Companies relying on such community projects and benefiting from the huge manpower provided by these communities cannot take total control of them. Though they can influence them by offering technological support in the form of contributions, they have to take into account the will and motivation of the community to make sure they still benefit from it. They have to balance between their agenda and the desires of the community. Companies will eventually take benefit from the project, but they have to do so by playing fair and accepting that their views are not shared by all project members. They have to support initiatives which are good for the project, but do not directly serve their interests. Why would they do so? Because they need to partner with the community to be considered a nice player to stay relevant and influential. This attitude, to me, creates shared value, both for the community and for the company.
For an employee of a free software company, this combination of working for a company and for the greater good is a compelling vision: by working for a company that shares a lot, they have a sense of working on something greater than just their own business. By helping produce software that can be used to the benefit of anyone around the world, they have a feeling of fulfilment, contributing to the global enhancement of societies.
The advantage of the open source development model is that anyone who has access to a decent Internet connection can get access to all the FOSS knowledge (by downloading the source code of the programs) and participate in the process of improving the products by sending improvement suggestions. Obviously, this can be done worldwide–the only prerequisite being sufficient Internet infrastructure and working computer hardware. The work of NGOs, such as Linux4Afrika, help accelerate the penetration of the market in developing countries by providing support, and by teaching classes at very low costs.
I believe companies working in the FOSS ecosystem definitely create shared value. By giving away their software for free, these companies make it accessible to all. By using processes based on the Internet, they make it possible for virtually anyone connected to the Internet to participate in their development and support communities. And finally, by publishing the source code, they allow anyone to take a look at how cutting-edge software is written and learn from it.
The current financial success of free software companies shows that it is possible to combine the ideal of doing something good and make money out of it, measuring their performance on a multi-dimensional scale and not only in financial terms. This success is proof that the business models built around the open source development model are fast-growing, robust, and sustainable.
On October 7th 2011, Red Hat has announced the acquisition of a company called Gluster, which has developed a distributed NAS technology based on open standards. This technology is included in a software appliance that can be deployed to share files over the network.
Why is this an interesting move ? Because NAS is ideal to store unstructured data, and that is the area that grows the fastest in the storage industry.
But what is structured data as opposed to unstructured ? These are entries that follow a strict definition: such as defined numbers (order numbers inside a company for example) or character strings (such as like customer IDs), etc. SANs (Storage Area Networks), such as Fiber Channel and iSCSI, are generally a good solution to store this structured data – in general in a database. However, NAS is the right solution for the incredible quantity of data that is produced every day from various sources (sensors, digital cameras, spreadsheets, presentations, etc.). According to an ESG report, the market for NAS will grow by 72% compound annual growth rate (CAGR) from 2010 to 2015 !
IT departments wanting to setup a network-attached storage environment had so far two main options:
- a simple NFS (network file system) server. That simple and cheap solution can be installed on any Linux or Unix server. However, this centralized solution concentrates the file accesses on on single server. Replication, failover and disaster recovery are limited, customized and cumbersome processes and the single server can become a performance bottleneck.
- dedicated appliances based on proprietary technology from EMC, NetApp, etc. Although they have very powerful features and are nicely integrated in enterprise environments, they are very expensive.
What most organizations have been asking, though, is to first to reduce the costs of storing this data that grows at incredible rates and second, have the capability to “burst” and leverage cloud capabilities, such as Amazon’s S3 while managing hybrid environments in an easy manner. Yet legacy solutions cannot offer solutions that cover these needs, and that is precisely why Gluster was developed.
I was fortunate enough to go to Mountain View, CA for a training with the Gluster people and discover their technology that is now called Red hat Storage.
The three strengths of Gluster are its scalability (a cluster can contain up to 64 nodes -supported- and way beyond), its manageability (you manage your public and private cloud storage blocks from one single point of view) and reliability (high-availability is built-in and there is no centralized metadata server, hence no single point of failure).
The Gluster infrastructure is based on commodity hardware, i.e. x86_64 servers from HP, Dell or SuperMicro, with direct attached storage (DAS) at disposal, e.g. the disks that are shipped inside the server. Recommended configuration is to have the OS on two disks (RAID1) and the data on twelve remaining disks (RAID6). This storage space will be put at disposal inside the Gluster environment through the network. No need for an expensive array: just take the servers you already know and Gluster will transform them into storage boxes !
From an architectural point of view, it is very important to mention that, although the technology is called GlusterFS, Gluster is not yet another file system. Gluster leverages standard file systems (such as XFS in the software appliance supported by Red Hat) and provides mechanisms to access the data across multiple servers.
The Gluster architecture is based on four elements (the bricks, the nodes, the volumes and the clients) and looks like this:
[Picture courtesy of Red Hat]
- the node: the Gluster software is installed on our commodity hardware server and on RHEL. This combination is called a storage node.
- the brick: the storage available to the OS, for example the RAID disks, will be formatted with a standard XFS (with extended attributes) and mounted to a certain mount point. A brick equals a mount point.
- the volumes: Gluster will play a sort of LVM role by managing bricks distributed across several nodes as one single mount point over the network.
- the clients are computers which access the data. They can be standard Windows clients (vis CIFS), NFS clients, or they can use a specific Gluster client that provides enhancements over NFS, in terms of high-availability.
Example 1 of a Gluster deployment
Let’s take an example : we have two servers -node01 and node02- running RHEL and Gluster. These two servers are identical and have, for the sake of simplicity, one drive on which we want to store data. This drive is formatted with XFS and mounted to, for instance, /brick1. This directory (and mount point) is identical on the two servers node01 and node02, to manage them more easily.
What happens next is that we create one Gluster volume, called volume01 -how creative !- from each brick available on the two servers. As I mentioned above, Gluster will play a sort of LVM role, by creating one logical disk from the two distributed disks attached to node01 and node02.
It means concretely that if I mount the volume via the network from another computer, called client1 (for example via the Gluster client), I would do the following command:
[root@client1]# mount -t glusterfs node01:/volume1
and I would have access to the capacity of both drives via the network. From a client perspective, no matter what new files I would store, no matter files I would read, I would not know that the underlying data is actually distributed across multiple nodes. Moreover, if I were an administrator of the servers, I could access the files via their mount point without even knowing that Gluster is running, because it leverages the standard components of a Linux infrastructure.
Example 2 of a Gluster deployment
In this example, two business units (marketing and legal) need two different volumes, isolated from each other. We will have roughly the same configuration as before, but with two data disks per server. Each disk on the server will be dedicated either to legal or to marketing. From these two disks, we will then create two volumes, one called marketing, the other one legal, that will be mounted by their respective clients.
How are the files stored ?
In our first example, when the client wants to store a word processing file file called “myfile.odt” at a specific location on the volume (for example /gluster/myplace ), Gluster will take in account the complete path to the file (in our example /gluster/myplace/myfile.odt) and a mechanism called EHA (elastic hashing algorithm), based on the Davies-Meyer algorithm, will compute a hash that will then indicate on which node and on which disk the file will be stored. When the file must be retrieved, the path to the file is given by the client, Gluster will compute the hash and will then be able to find the file on the given node.
The interesting part of this EHA is that if you store, for example 100 files on a two nodes cluster, like in our first example, the distribution rate will be quite equal. After having saved the 100 files on the volume, and regardless of the complexity of their names, we will end up having roughly 50 files on the node01 and roughly 50 files on node02. Why is that so powerful ? Because instead of having one single server becoming a bottleneck, the cluster can spread the files across its nodes and ensure that the network bandwidth will not become an issue, thus generating a highly scalable solution.
One important thing is also that there is no centralized meta-data server. The hash is computed, for example by the client, for every access and hence removes a huge single point of failure compared to competitive architectures. If the meta-data is broken, the data (and it can be up to petabaytes of it !) is simply gone, there is no way to find it back. Gluster, on the other hand, has no such centralized architecture, and the beauty of it is that there is no proprietary file system underneath. Every file can be accessed from a standard XFS file system, even if the Gluster deamon is shut down on the machine.
Mount type glusterfs ?
As you can see in the examples above, it is possible to mount the volumes with the mount types NFS or glusterfs. Indeed, in order to mount a Gluster volume in a “native” mode, the client needs a specific package installed. The advantage of this client is that high-availability is built-in (i.e. if a node fails, access to the replicated data is possible without any disruption) and also, the client is able to use the EHA to calculate itself the position of a certain file inside the cluster and hence will talk directly to the node that contains the data, thus reducing the speed to access data and reducing the network traffic.
What about High-Availability ?
Gluster offers the possibility to mirror bricks across the network. This means that if a node fails, the data will still be available via another node. It is also of course possible to combine both the distribution of files and the replication with, for example four disks : two used to save the data and two that are their replicas. After the node or the brick are available again, Gluster will use a technology called self-healing and will update -in the background- all the data that was modified during the downtime so that the data is identical on both replica after the self-healing process is done.
When it comes to disaster-recovery, it is also possible to use a two-way technology called georeplication that maintains asynchronously a copy of the data at another site. The recovery site can be a Gluster cluster, or another type of storage.
What are the advantages for my organization ?
Gluster is a great technology that brings a lot of advantages. The highlights are definitely that Gluster :
- increases the availability of the data by replicating the data and by having no meta-data server i.e. no single point of failure
- manages the data better. The command-line interface is very intuitive and is able to manage petabytes of data in an easy way
- scales to petabytes level, by spreading linearly the data across multiple nodes, hence avoiding the creation of bottlenecks
- lowers the costs of storage by using commodity hardware
I think that Red Hat was very smart to extend its portfolio to storage. Indeed, after the commoditization of the server market from proprietary Unix architectures to standard Linux servers, it is time for the storage vendors to become more open and dramatically increase their affordability. This is just the beginning…
I use some Google services (such as Gmail) and I respect Google’s focus on innovation and its contribution to some Free software projects, but I must admit that I try to be as careful as possible when it comes to privacy. For instance, I tend to use OpenStreetMap instead of Google Maps when I look for a simple map. I use Firefox instead of the default web browser on my Android phone and I never let the Android’s GPS enabled when I do not use it.
After four years spent at HP, I accepted an offer to work for Red Hat, thus moving from Stuttgart to Munich.
I lived four amazing years at HP, surrounded by fantastic and dedicated people. I learned a tremendous amount of things. I could acquire a sound technical knowledge about enterprise IT environments and also learned a lot from my mentor and my colleagues. I also attended very useful and interesting sales and soft skills trainings.
This change to Red Hat is quite a challenge. First of all, the company’s business is radically different. I always found right to sell Free and Open Source Software and this is a great opportunity to do my job according to my ethical principles. Moreover, I change from the biggest IT company in the world, with 300,000 employees (not counting all the contractors and partners) to a roughly 4,000 persons company. Red Hat is clearly not a start-up any more, but it is way smaller and things need to be handled in a creative way.
I’ll take over a new role in Red Hat to support systems integrators, OEMs (such as HP) and ISVs from a presales perspective at the EMEA level. I look forward to passing my Red Hat Certified Engineer certification and to learning a lot. The fact that KVM is installed and ready to create virtual machines on all PCs inside the company is a great sign of geekiness and that is already a good start!