An IT Knowledge Worker
Compute resources at LRZ: Server management with Kubernetes Foto: LRZ
It was only after school that Johannes Halemba became really successful at learning new things. "I was a mediocre student, I only liked computer science," admits the IT specialist. After graduating from high school, he finished school and started his training at the Leibniz Supercomputing Centre (LRZ) to become an IT specialist in systems integration. "In this job, you install and operate software, look after IT infrastructure such as servers and, if functionalities are missing or tasks need to be automated, you also do programming. I really appreciated this wide range of activities," says Johannes. "The LRZ was the ideal playground, I was able to try out a wide variety of tasks and applications, and I realised that learning new things can be a lot of fun".
Johannes Halemba's career will reassure millions of parents of rebellious children unwilling to study, it will encourage companies to offer a lot more training and flexible working hours. Meanwhile, recruiters and human resources professionals could be persuaded to stop focusing solely on school marks in job applications. After finishing his apprenticeship, Johannes becomes a knowledge worker in IT, then he completed his technical college degree and enrolled at the University of Applied Sciences in Munich to study business informatics. In 2020 he received his bachelor's degree and two years later his master's degree: eight years working at the LRZ and still studying. "Respect," says his colleague Winfried Raab, one of the trainers and head of the Infrastructure Operations, Servers and Services (ITS) department at the LRZ: "Such way for training requires a lot of discipline.
Accumulating overtime hours for exam periods
Johannes Halemba himself is glad that his academic training has come to an end: "I don't know if I would recommend the marathon to anyone," he says with a grinning face. "You have few holidays, hardly any weekends, and you do it for years. But I didn't want to miss out on the practical side of my studies, and just studying wasn't an option either". He attended the technical secondary school in Freising while working and completed his studies as a part-time employee at the LRZ. Johannes started with a 25-per-cent position and worked 20 hours a week in his final year. During the semester breaks, he has been able to reduce the overtime he accumulated. This approach works with tasks that are not time-critical, thanks to a lot of planning and the high level of flexibility in the team. Johannes has always stepped in when support was needed. He keeps fit for his studies and his work by working out and he relaxes by reading. "I never had to do unskilled jobs to make ends meet," he says, describing the benefits of his study marathon. "I had my work and it had a lot to do with my studies."
This is both efficient and pragmatically planned. And that is very characteristic of Johannes Halemba. The information systems specialist describes himself as analytical and solution-oriented: There's no such thing as can't. He tries things out, he programmes, and he tinkers and fiddles until something works. "Evaluating a situation, working out a target situation and then implementing it - that's exciting. Friends and family ask him for advice on computers, and his colleagues like his hands-on attitude and attentive personality: "It is his openness, not his will to convince, that creates a good atmosphere in discussions," says his trainer and mentor Raab. "His skills go far beyond the purely technical, he impresses me above all as a person. His sincerity and down-to-earthness are among his most valuable qualities.
The IT specialist's curiosity has also given him a broad perspective: During his training, Johannes passed through almost every department at the LRZ. He installed workstations and servers for the PC group. Answered users' questions at the service desk. He replaced WLAN access points or switches for the university's communication networks department and learned what happens when an email is sent and received in the computer centre. I also learnt to use Linux - "I was fascinated by the ability to administer a server entirely from the command line, without a graphical user interface". As a part-time employee, he installed servers for ITS and configured applications and virtual machines on them: "Doing the same thing every day is not really my thing," says Johannes. "I need challenges.
Energy Efficiency and Automation
Servers and cloud computing are the common thread running through his studies. For his bachelor's thesis, Johannes is looking at how virtualisation can be used to better utilise servers and reduce power consumption in data centres. Companies have been using virtualisation for years to save space or make better use of hardware. Instead of buying hardware, servers and other components, their functions are copied digitally and supplemented with software packages or containers. At the LRZ, around 2,500 virtual servers run on 90 rack servers from Hewlett-Packard, and another 2,000 run in the LRZ Compute Cloud, which is based on more than 100 computing nodes from Lenovo.
This is the system that Johannes uses as a research object. For his bachelor's thesis, Johannes visualises the measured values obtained from the data cloud, he extends scripts or command lists for this purpose and creates a monitoring system for the LRZ Compute Cloud: "That's how we got an insight into the use of the cloud, it was there all at once," says Niels Fallenbeck, PhD in computer science and co-responsible for cloud services at ITS. I appreciate Johannes' independence, this "let's try it out" mentality. The result of his bachelor's thesis is once again an algorithm that sets up virtual servers on computers in such a way that they use as few computing nodes as possible and any resources can be shut down to save energy.
His master's thesis is also about cloud computing. But now it's about the efficiency of resource management. "Whenever I set up a server and was interrupted, I always asked myself what had already been done and what hadn't," he says describing a common problem. This problem grows when you have to monitor a large number of resources or when teams are working together. For his master's thesis, he is developing a management system for servers. "GitLab & Kubernetes - Integration of a GitOps repository structure based on CI/CD pipelines for the provision of containerised applications" is the title, and it is worth explaining: the freely available software Kubernetes has proven itself in the operation of at least three servers - both virtual and real. It forms a kind of data cloud for technology, hardware can also be connected to clusters with it, it accommodates software, containers, tools and applications and distributes them independently to existing systems. And it duplicates or scales applications and programmes as needed if they are to be used multiple times or - for security reasons - stored in multiple locations. With this redundancy, data centres and IT departments can increase reliability and keep servers and software running in the event of technical problems and hardware failures.
For greater clarity, Johannes links Kubernetes to GitLab. "This is a database that development teams use to coordinate. It lists all the programming progress of a piece of software and ensures that everyone in the team is working with the latest version," explains the young scientist. This principle can also be applied to the management of IT infrastructures, where the database lists technical components. In the case of server management, however, it shows who has deleted, added or updated which servers, software or tools, and when. In combination with GitLab, Kubernetes simplifies server management and ensures that changes to the structure or programmes are made according to defined workflows: This is what IT specialists call "continuous integration" and "continuous deployment", or "CI/CD" for short: "Server clusters and applications are no longer configured manually, but created, deleted and managed from GitLab, and in-house developments can be integrated without much effort," Johannes explains, summarising his system. "At the beginning of my apprenticeship, I spent hours uploading software to servers manually. Now, everything is so automated that you can actually define an infrastructure in code, press a button, go for a coffee, and when you come back, everything is set up".
Taking time out to enjoy freedom
In his master's thesis, Johannes Halemba presented a blueprint for the administration of a Kubernetes cluster, thereby laying the foundation for a new LRZ service. "Kubernetes as a Service" will soon be offered as a tool to departments and research organisations. "All my LRZ experience went into this work; it was the end point and conclusion of my IT education," says the newly graduated master's student. "Of course I will continue to learn more at work, but now I want to catch up on free time and travel." Johannes will be watching from afar how his plan is put into practice: "I need a break from IT now," he says. Therefore, the IT knowledge worker is making travel plans. Canada is one of his favourite destinations. He wants to leave in April, and he quit his position at the LRZ for his sabbatical. Return to Boltzmannstrasse in Garching? He would not rule it out. But that will be another story. "If I've paved the way for others with my training, so that they can get as far as I have, then that would be great," he says. But for now, he's living his life's motto: "Don't stand still, keep learning, keep gaining experience - new paths are created by walking. (vs)
Johannes Halemba: Training and study at LRZ
More Persons to Watch and young researchers, you should know:
Pascal Jungbluth, LMU: Computer Science and Accelerators
Ivana Jovanovic-Buha, TUM: Computational Mathematics, Simulation, artificial intelligence
Elisabeth Mayer, LRZ: Computer Science, media, virtual reality
Amir Raoofy, LRZ: Computer Science and Future Computing
Mohamad Hayek, LRZ: Computer Science, Data Transfer
Sophia Grundner-Culemann, LMU: Computer Science, Quantum Computing
Bengisu Elis, TUM: Computer Science, HPC, Future Computing
Daniëlle Schumann, LMU: Computer Science, Quantum Computing