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Due to the nature of the virtualized applications, whose function is to regulate, control, command and transmit information relating to the operation, management and maintenance of an electrical substation, the virtualization base must meet the challenges of reliability, performance and availability.
Features
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SEAPATH currently or will include the following features:
- Ecosystem agnostic, easily used and extended by third parties
- Hardware agnostic: can be installed on different types of servers and architectures (x86, ARM, etc.)
- Vendor agnostic: a heterogeneous variety of virtual machines can be
- deployed and managed on the platform.
- Open source: released under a permissive open source license (Apache-2.0), enabling effortless adoption, customization, integration into existing projects, and commercialization opportunities for users.
- On-going integration with other LF Energy Projects from Digital Substations Automation Systems (DSAS) such as LF Energy CoMPAS, LF Energy FledgePOWER, and OpenSCD.
- High performance, ready for IEC 61850 applications
- Real-time capabilities: can host applications with determinism and performance needs.
- Time synchronization: natively support NTP and PTP (IEEE 1588) synchronizations.
- Resilience, robust for mission-critical systems
- High availability and clustering:
- offers cluster functionalities to guarantee
- availability in case of hardware or software failures.
- Distributed storage: data and disk images
- of the virtual machines are replicated and synchronized
- to guarantee its integrity and availability on the cluster.
- Automatic updates: The system can be automatically updated from a remote server.
- Infrastructure as code, allowing automated and remote system management
- Configuration: initial configuration is done using scripted tasks, ensuring exact replication of desired operations and avoiding manual errors.
- Administration:
- can be easily
- managed from a remote machine connected to the network as well as by an administrator on site.
- Intensive testing, guaranteeing capabilities and avoiding regression
- Continuous integration: Every development on the platform must pass more than 700 unit tests, real time tests and latency tests.
- Testing-driven cybersecurity approach: each requirement is ensured through extensive unit tests.
SEAPATH architecture
The virtualisation platform uses the following open source tools:
- QEMU: Emulator and virtualizer that can perform hardware virtualization.
- KVM: Linux module that offers virtualization extensions so the machine is capable of functioning as a hypervisor.
- Libvirt: virtualization API and management tool used to configure virtual machines simulated hardware.
- Pacemaker: High availability resource manager that offers clustering functionalities. It is used in combination with its plugins Corosync + STONITH.
- Ceph: Scalable distributed-storage tool that offers persistent storage within a cluster.
- Open vSwitch: Multilayer virtual switch designed to manage massive network automation in virtualization environments.
Ansible: Infrastructure management tool that simplifies orchestration of machines through declarative configuration.
A Yocto distribution
The Yocto Project is a Linux Foundation collaborative open source project whose goal is to produce tools and processes that enable the creation of Linux distributions for embedded and IoT software that are independent of the underlying architecture of the embedded hardware.
The Yocto Project provides interoperable tools, metadata, and processes that enable the rapid, repeatable development of Linux-based embedded systems in which every aspect of the development process can be customized.
The Layer Model simultaneously supports collaboration and customization. Layers are repositories that contain related sets of instructions that tell the OpenEmbedded build system what to do. You can collaborate, share, and reuse layers.
Layers can contain changes to previous instructions or settings at any time. This powerful override capability is what allows you to customize previously supplied collaborative or community layers to suit your product requirements.
How is high availability ensured in the cluster?
- Resource management: communication between the different machines within a group is managed by Pacemaker and two of its plugins. Corosync is used for the intercluster communication and the Heartbeat mechanism while STONITH implements the fencing system.
- Distributed storage: All data written to disks is replicated and synchronised within the group members by using the CEPH tool. Note that from a user point of view only a single instance of each VM can be started on the system at the same time.
- Intelligent network: The different machines on the cluster are connected on the layer level (OSI model) using OpenVSwitch and DPDK for its administration and management.