Customer Story
Datev
DATEV monitors one of the most complex and security-sensitive IT landscapes in Europe using Icinga’s automation capabilities, plugin flexibility, and scalable architecture – all while meeting the strictest requirements for data protection and compliance.
DATEV provides the technological backbone for collaboration between SMEs and their tax advisors, offering a comprehensive portfolio that spans over 200 PC applications, cloud-based services, data center hosting, outsourcing, IT security, and digital archiving. Consulting and educational services complement the offering across Germany and selected European countries.
DATEV eG is the third-largest provider of business software in Germany and one of the leading IT service providers in Europe. Founded in 1966 and headquartered in Nuremberg, the cooperative generated €1.51 billion in revenue in fiscal year 2024. With more than 9,000 employees, DATEV supports more than 900,000 customers, including tax consulting firms, companies, self-employed professionals, municipalities, associations, and institutions – reaching over 2.8 million organizations through its digital ecosystem.
The Challenge
A Complex, Rapidly Evolving and Highly Regulated IT Landscape
As a key technology enabler in the German economy, DATEV carries responsibilities that extend far beyond traditional software development. It maintains a critical IT infrastructure that supports secure financial and legal operations across multiple industries – and as such, its systems are complex, diverse, and tightly regulated.
Over time, the environment has grown into a highly heterogeneous mix of platforms and technologies:
- a classic data center with one of Europe’s largest IBM mainframe environments,
- a cloud-native data center designed for microservices and DevOps,
- and integrations with public cloud providers such as AWS, Azure, and Google Cloud Platform.
Monitoring across this fragmented landscape must not only ensure real-time visibility and security compliance, but also blend smoothly into existing IT service processes.
Our IT has grown over decades and consists of a mix of classic servers, mainframes, microservices, and cloud technologies. Monitoring this heterogeneous environment presents us with enormous challenges.
The Monitoring Team
The Icinga-based monitoring platform of DATEV is managed by a core team led by Gunter Geib, who drives the strategic direction of monitoring and observability at DATEV. Alexander Heinhold and Konstantin Fanselow are responsible for the platform’s operation, automation, and evolution. They are supported by two additional colleagues who handle customer-specific monitoring setups, act as the interface to internal DATEV clients, and implement requested changes – including the development or integration of new plugins when needed.
We’ve turned monitoring into a centralized internal service. Our colleagues no longer worry about tooling – they submit a request, and we handle the rest.
The Solution
One of the best features of Icinga for us is the easy extensibility through monitoring plugins.
Automation, Flexibility, and High Availability with Icinga
DATEV has relied on Icinga as its central monitoring platform for over a decade. From the beginning, the focus has been on automation and self-configuration.
Gunter Geib explains “Back then, we managed to configure the monitoring tool almost fully automatically with Icinga 1. Today, we are using Icinga 2, and the fundamental approach remains the same: self-instrumentation, meaning self-configuration of Icinga.”
Monitoring configurations are generated via a centralized script, based on data collected from multiple CMDBs and internal sources. This script dynamically creates and updates Icinga config files. The Icinga Director is not used – the team opted for maximum flexibility and control via custom scripting.
We cannot use a monitoring tool that does not fit into our security architecture. With Icinga, we have found a solution that effortlessly integrates into our highly fragmented networks.
The infrastructure of DATEV is segmented and secured by design. To ensure monitoring coverage across all zones, DATEV built a multi-tiered satellite architecture:
- 4 high-availability satellite pairs in the classic data center
- 3 satellite pairs in the cloud environment
- 5 satellite pairs in the cloud-native environment, specifically for network separation, not load distribution
As Gunter Geib puts it, “This architectural approach – chaining satellites where one acts as a jump point and gateway to the next – is really cool. It has enabled us to do things that wouldn’t have been possible otherwise.”
Success
A Centralized, Scalable Monitoring Service
Today, DATEV monitors over 50,000 server units, along with cloud services, databases, and network infrastructure. Every server deployed receives a base monitoring setup automatically, with additional checks defined by the service owner.
All monitoring services across DATEV are now centralized, replacing legacy tools and shadow IT. As Konstantin states contently: “Previously, each department had its own monitoring solutions – that was inefficient. With Icinga, we have created a central service model that ensures uniform monitoring and high data quality.”
Transparency is core to the model. Around 8000 DATEV employees have access to the Icinga web interface. There is no information hiding – relevant information is openly visible depending on user role. Standard users can view health checks and search across hostnames, IPs, and service IDs.
We chose Icinga as our umbrella tool – and I honestly don’t think there are many solutions out there that can do this as well as Icinga.
Icinga serves as the umbrella monitoring platform for DATEV: while additional monitoring tools exist, all send their alerts to Icinga, which acts as a centralized aggregation point. From there, notifications are forwarded to an event management system that enriches the data with metadata and then routes incidents to the appropriate ticketing or voice-based alerting systems.
DATEV also collaborates actively with Icinga partner NETWAYS and the Icinga team on improvements and new features. A major joint project in recent years was the development of advanced Hyper-V monitoring capabilities.
We’re really interested in the new Icinga Notifications feature. That’s definitely something we plan to explore in depth and evaluate in a POC.
Looking Ahead: Cloud-Native, Observability-First
DATEV is undergoing a long-term transformation toward cloud-native-only operations. The legacy data center is planned to be phased out by the end of the decade, and observability is becoming the new standard for application insights.
DATEV is also investing in OpenTelemetry and observability platforms like Grafana Cloud, while continuing to rely on Icinga for infrastructure and system-level monitoring.
Our classic data center will be history soon. Icinga must find its place in the cloud-native world – and we are excited to see the direction the team will take.
Outcomes
- Automated configuration reduces manual workload
- Over 50,000 systems monitored – with full IT transparency
- High-availability satellite architecture ensures secure coverage across network zones
- Central aggregation of all alerts via Icinga as umbrella monitoring tool
- Full integration with CMDB, event management, ticketing, and on-call systems
- Open source extensibility for custom plugin development
- Future-proof with clear vision for cloud-native monitoring and OpenTelemetry
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