# Railway Cloud: Management and Orchestration Functionality Designed as Microservices
## 6 Railway Cloud Issues Regarding Safety and Security  
The migration of railway control systems, real-time monitoring, and operation management to the cloud bring about challenges in terms of railway safety and security, and railway cloud management plays an important role in achieving the necessary requirements.  
The aim of railway safety is to protect passengers, the environment, and railway assets by applying automatic protection functions. Railway safety requires understanding potential risks for the malfunctioning of equipment and software errors and to minimise their impact. The proposed railway cloud management system could assist in these processes. Usually, the proper automatic protection functions include the monitoring of system performance, the safe delivery of updates, and risk management. Functional railway safety requires performance assessment of the cloud and virtualised resources, identification of the risks for achievement of the required performance, risk mitigation by redundancy in the system design, and proving a performance achievement. For virtualised resources, it is important to provide operation continuity while minimising recovery time, which means that high cloud availability could be achieved by railway system resilience instead of individual equipment resilience. The required level of resilience can be achieved by distributed railway clouds and increasing the railway cluster's redundancy instances for on-time replacements. In the cloud, railway operators can continuously monitor workflows to discover faults and errors, as well as network traffic anomalies, or to balance the load. An important factor for railway system resilience is also the cloud archiving capabilities that facilitate recovery from failures.  
The aim of railway cloud security is to protect cloud-based infrastructure, applications, and data. The main railway cloud security benefits are as follows:  
* Lower investments and reduced operational costs due to the security and compliance framework respected by cloud services providers.
* Improved reliability and availability based on the authorized access to data and centralized security control.
* Flexible cloud security scaling with evolving requirements.
* Improved protection against distributed denial of service via continuous attack monitoring and dispersing.  
The main railway cloud components and data that must be protected include the following: software images repository, cloud catalogue information for hardware and software resources, cloudified railway functions information, software components and their associated data, private keys, certificates and credentials, railway cloud and cloudified railway function monitoring, etc.  
The requirements of railway cloud security could be derived through the analysis of threats. For example, a railway cloud API attack could affect cloud deployments through a compromised virtualisation layer, which may result in information disclosure or tampering, or the denial of a service. Such unsecured cloud API and the lack of authorisation could impact availability, integrity, and confidentiality. Some of the common requirements to achieve cloud security can be found in published security guidelines and best practices. They include certificate management, cloud network segmentation and traffic filtering, identity authentication, access management, security configuration by cloud virtualisation level, secure lifecycle of the cloudified functions and applications, protection of software images, logging, monitoring, and alerting of threats, and security audit. In addition, secured access to encrypted storage, hardware, and network security protection must be provided.