Many clients wish to know what the hardware and operating system requirements are for a Delft-FEWS client-server system. On this page you can find a list of specifications. If you have any question about the list, or you do not see the operating system of your choice: please contact Delft-FEWS Support. This list is not exhaustive.
Components
Operating Systems
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JDK
Embedded JDK that can be replaced
Delft-FEWS binaries contain an embedded JRE. It should be possible to replace the embedded version of the JRE with a commercial JDK or OpenJDK of choice.
The Delft-FEWS binaries contain a embedded stripped-down JRE (Java Runtime Environment) based on Amazon Coretto OpenJDK. This package is referred to as the Delft-FEWS base build. These OS specfic JREs can be found in folders bin/linux/jre and bin\windows\jre. These JREs can be easily replaced by any other open source or commercially supported version of the same major Java version. Since Operator Clients / Stand Alone Clients and and Forecasting Shell Server mostly run in a controlled (and secured) environment, it is not necessary to have these jre subfolders replaced. The decision to arrange additional 'support for Java' is up to the end user of Delft-FEWS. If crucial security fixes are required in the embedded jre in the Delft-FEWS binary package, Deltares may distribute updated base builds. Optionally, distribution of new base builds can be done by upload via the Admin Interface.
Some models / model adapters may require a separate JDK installed
The OpenJDK supplied in the Delft-FEWS binaries is not the full JDK. Instead it is bundled by the jlink executable to a stripped-down JRE with only the parts that the OC / FSS / CM / MC require. This economizes the number of bytes that needs to be copied to every FSS host. This is different from 2017.02 and before where the full JRE was normally installed. If a model adapter or external model to be run by the Forecasting Shell or Operator Client is also using this stripped down version of the JRE for its operation, it is possible that some of the java classes required are missing from the shipped jre and the adapter or model won't be able to run properly. It is the responsibility of the application managers / model configurators to ensure that their adapter and models requiring Java are already supplied with the correct Java Runtime modules. It is essential that the Forecasting Shell Launcher startup script should not be contaminated by additional path variables, instead the models should contain their own embedded jre. See the General Adapter Module for more details.
Server for workflow management, event processing, sending system alerts and cleaning up expired records. Synchronizes from other Master Controllers in multi-MC systems. Multi-MC systems are useful for redundancy and / or for cooperation between organizations.
Minimum requirements
OS minimum +1 GB RAM (multi Master Controller systems +2 GB)
The components mentioned above can all be located on one (powerful) server or each on an individual machine, with all possible configurations in between. It is however common practice to separate the Forecasting Shell server from the Master Controller server. When using multiple machines it is essential that all machines have matching clocks. This can be achieved by making use of one and the same ntp server.
A typical configuration is:
Database Server
Master Controller server running Master Controller(s), Apache Tomcat for Admin Interface
Forecasting Shell Server(s)
Open Archive Server
Typically in a dual Master Controller setup every Master Controller has its own machine so that maintenance can take place without offline time.
Virtualization
It is very well possible to deploy the Delft-FEWS components in virtualized environments. The Deltares ICT team has most experience with Delft-FEWS on VMWare VSphere with in-depth knowledge but Delft-FEWS is also known to run on Microsoft Hyper-V. Virtualization of the Delft-FEWS back-end services can generally be done without problems. The Forecast modelling software determine requirements or limitations with respect to virtualization of the Forecasting Shells.
Security
Read more about the shared responsibility model.>>
Security - Shared responsibility model for Delft-FEWS system installations
The Delft-FEWS server software historically was most commonly installed on-premise at the customer site on servers that were not directly connected to the internet. Nowadays, there are also more and more Delft-FEWS applications that are being deployed in the cloud. This means security standards and guidelines for the installation of live systems have become more critical than ever before. Delft-FEWS runs on top of a stack of components like 3rd party components: databases, Tomcat and an embedded JRE.
It is the primary responsibility of the customer to apply the latest security fixes to the OS, database, Tomcat and all other components.
For updates for the embedded JRE it is recommended to contact Deltares. The role of Deltares is to supply guidelines and facilitate security best practices where possible. Deltares maintains a separate section on the WIKI especially for system and database administrators. To view these pages, personal credentials can be supplied. These pages contain highly detailed information for installing and upgrading Delft-FEWS, amongst others about security aspects. For the near future it is foreseen that more and more managed services from cloud providers (e.g. Tomcat, database) can be applied. All Delft-FEWS developers are security aware and evaluate the existing and potential vulnerabilities on a regular basis. Together with our colleagues from our ICT department they meet regularly to discuss (potential) improvements for each Delft-FEWS release.
Tomcat
Tomcat is required for the deployment of the Admin Interface, Database HTTPS Proxy, Fews Webservices and the Deltares Open Archive. Tomcat is installed and maintained by the customer organization. Deltares indicates which version of tomcat is compatible with / required for which version of Delft-FEWS. All security related aspects available in Tomcat can be applied and are under the responsibility of the customer organization.
For Admin Interface clients / proxies that are exposed to the internet it is crucial that the highest stable release version of Tomcat with security fixes is used. This prevents exposure from common vulnerabilities and exposures (CVEs).
For releases up to 2022.02, any tomcat9 version should be able to work for our Admin Interface / HttpProxy / PI Service / ArchiveServer web containers. This requires that the correct Java version matching the indicated JRE version for the Delft-FEWS release version is used and this Java version must be compatible with the Tomcat distribution.
Run Tomcat server as an unprivileged user and NOT root / Administrator.
Tomcat user has read-only permission to the contents of the conf/, bin/, and lib/ directories in ${CATALINA_HOME.}.
Limit the Tomcat user’s access and permissions to only the needed directories and files work / temp / webapps / logs.
Uninstall all non-essential web applications in the webapps/ directory, including the applications that come with Tomcat.
JRE/Java
In several components of Delft-FEWS a (stripped down) version of Java/JRE (Java Runtime Environment) is embedded. This JRE folder is a recognizable and standard part of the Delft-FEWS binary package for Operator Clients and Forecasting Shell Servers. This means that Deltares delivers an optimized (and minimal) Java Runtime Environment based on Amazon Corretto's series. This so-called base-build can be updated and Deltares will release new base-builds if required. Since the JRE folder is recognizable within the Delft-FEWS binaries, organizations may decide to replace this JRE folder in favour of another (compatible) version of the JRE. It is certainly possible to use a different provider (e.g. Oracle Sun or the openJDK). Replacing the JRE can be done by creating a soft link to the JRE directory or by replacing the JRE folder.
Local databases (Operator Client, Stand Alone)
In recent versions of Delft-FEWS there is no need for a local database (datastore) for an Operator Client (OC) in a client-server environment. Although it is still possible to have a 'fully synchronized' (local) database in an OC or to create a 'replicate' of the central database to continue working as a standalone (SA). There are two data formats available: Derby or Firebird. These are just local files (just like any other file on the file system) and they do not require any software installed for managing it. The Delft-FEWS Operator Client or Stand Alone application just reads from and writes to this database format. This mechanism cannot be used as a ‘hub’ to enter other server side components.
Central Database access
Delft-FEWS can be equipped with one of three common brands of central databases: Oracle, PostgreSQL or MS SQLServer. Access to the central database is required for several Delft-FEWS servers side components. These components are normally located behind the organization's firewall (same network) or in the secure domain of a data centre or cloud provider. Operator client access to this database is also required, but when set up from 'outside' the organization's network, a https (proxy) server (including IP whitelisting) should be in between. Deltares can provide this.
Forecasting Shells
The Delft-FEWS binaries folder should be made read-only.
Forecasting Shell Servers (FSS) should have limited permissions (rights). Only write access within their own directory.
Only provide access to the data feed shared folders for FSSs.
The account for installing should be different than the account running processes
When applying external simulation software, ensure the executables and other libraries have only permission to be run locally.
Operator clients
The Delft-FEWS binaries folder should be made read-only.
When using the optional JCEF browser, white-listing is used to grant access to webpages.
Multi-layered security approach
The inner layer is the central database (and optionally Deltares Open Archive).
The middle layer are Delft-FEWS components that communicate directly with the database using encryption.
The third layer (optional) is a reverse proxy to the database that can be accessed externally.
