Thoughts by: Sven Bernhardt, Richard Attemeyer, Torsten Winterberg, Stefan Kühnlein, Stefan Scheidt
A frequently discussed topic these days is the Micorservices architectural paradigm. Discussions on various internet blogs and forums are showing the trend that proponents of this approach are not tired of emphasizing why Microservices are different to a holistic SOA approach, when dealing with breaking up or avoiding monolithic software architectures.
For this reason it’s time for the Cattle Crew team, to take a closer look on this arising architectural style and the corresponding discussions from a different perspective.
Amongst others Martin Fowler published a blog about what is characteristic for Microservices and applications build on the foundation of this architectural style . According to this and other blog posts (see also , ), the goal of a Microservices approach is to avoid software systems to become monolithic, inflexible and hardly manageable, by splitting a system into modular, lightweight and maximum cohesive services. Applications build on this architecture should ensure the agility regarding changes caused by changed business requirements, because affected services of an application can simply be adapted and be redeployed independently from other components.
Effectively a Microservice is a in itself cohesive, atomic application, which fulfills a dedicated purpose. Therefore it encapsulates all needed elements, e.g. UIs, logic components, may also have its own separated persistent store and may run in a separate JVM, to ensure as less impairment to other services as possible. Furthermore the implementation technologies for a specific service may vary. For each service the best-fitting technology should be used; there should be no restrictions regarding the used technologies.
To ensure consistency as well as compatibility with already existing components in case of changes and to guarantee seamless release management of changed components, a Continuous Delivery procedure is indispensable for succeeding. In addition the implementation efficiency benefits from the Microservices approach, because different components may be developed in parallel. Communication between the services, if needed, is done via lightweight protocols such as HTTP. Well defined interfaces are depicting the service contracts.
Where there is light, there is also shadow…
One of the basic questions, we asked ourselves when discussing the Microservices approach, is how to determine respectively which metrics to use for evaluating, if a service is a Micorservice or not. Resulting from that it would be interesting what if it is no longer a Microservice: is it directly a monolithic service?
A clear definition about what are the differentiating and unique characteristics of a Microservice cannot be found. Metrics like lines of code or number of classes are no appropriate characteristics, so something spongy, like specific business functionality has to be taken as a distinctive mark for a real Microservice. But that’s not really measureable…
Besides the missing clarification about the Microservice term as such, building business applications using a modular Microservices architecture means a higher complexity than when using a classical monolithic approach. From conception to delivery to the operating this higher complexity may raise the following challenges:
- Right level of service granularity; not to coarse grained, not to fine-grained
- Comprehensible service distribution for scalability reasons and the corresponding monitoring
- Complex testing procedures because of loose coupling and service distribution
- Consistent and tolerant Error-handling, because a referenced service might be down for maintenance reasons (Timeouts, Retry mechanisms, etc.)
- Reliable message delivery
- Consistent transaction handling, because of cross-service communications using non-transactional protocols like HTTP mean the establishment of complex compensation mechanisms
- Guarantee of data synchronization and consistency, when services have their own and exclusive persistent stores
- Sophisticated Service Lifecycle Management, because every service has its own lifecycle including challenges like how to deal with incompatible interface changes
Another risk we see with a naive implementation of the Micorservices architecture is a fall-back to the days of distributed objects: Calling a magnitude of services is not a good idea because of latency and (missing) stability.
Microservices and SOA
When dealing with the Microservices approach it is conspicuous that at least one paragraph could often be found, stating something like “Microservices vs. SOA”, where it is depicted that Microservices and SOA are conceptually different. In this context the idea of SOA is often reduced to technology terms like WS* or ESB and therefore referred to as heavyweights. This definition of SOA only covers possible implementation details, because from a conceptual perspective SOA is also an architectural paradigm, making no premises regarding implementation details or the corresponding technologies to use for a concrete SOA implementation.
When looking at the sections before, describing Microservices-based architectures and its challenges, it can be stated that very similar concepts and challenges arise in SOA-style architectures, because characteristics for Service-oriented architectures are loose-coupling, standard-based and stable service contracts, distributed services and flexibility as well as agility regarding changing business requirements. The resulting challenges are nearly the same. As a reason for this, in our opinion the both approaches aren’t so different essentially.
SOA-style architectures historically often use SOAP-style communications. But regarding this fact we are observing a change: the number REST-style SOA services is growing. A trend which is mainly influenced by the increasing need of multi-channel support, e.g. for mobile devices, where REST-style communications by using a JSON-based data format is the preferred variant. The big software vendors, e.g. Oracle, also recognize this trend and therefore have extended out-of-the-box support for REST services.
In system architectures that are based on the SOA paradigm, an ESB is often used to integrate different enterprise applications. Classically it cares about routings, protocol as well as data transformations and service virtualization. So point-to-point integrations between systems can be avoided and makes an IT system landscape more flexible regarding adding new applications as well as services. In our opinion this can’t be called heavyweight and is indispensable for increasing agility.
Furthermore the microservices proponents do not say any word about service governance. This is also ok for some sorts of SOA services. We often differentiate services into public and private services. Systems consisting of multiple components are often organized as a set of collaborating private services . These interfaces are not published enterprise-wide and must therefore not adhere to more strict policies applied to public services. The offical / public interfaces of a system are in contrast published as public services.
Thus from our perspectives, Microservices are nothing new, but rather an implementation of the concept of private services.
Microservices architectures are primarily focusing on a local, application-based scope and provide a very flexible as well as modular approach for developing easy-to-extend applications. In summary it can be said that the Microservices architectural paradigm seams to deliver great benefits though it must be stated that the approach is not a completely new concept. Compared to that a SOA approach has a farsighted, global scope aiming at the enterprise level. From a SOA perspective, Microservices could be understood as private services, not necessarily exposing their functionalities for reusing them in other systems or services. But that is ok, because in service-oriented architectures one does not expose a service, when there is no need – which means no need for reuse in other applications or services – for it.
Taking all points discussed in this article into account, we would recommend that discussions about differences between Microservices and SOA should be avoided. Instead it should be evaluated how and if a coexistence of these two very similar approaches is possible to deliver the most valuable benefit for system architectures as possible, making IT system landscapes more flexible and therefore promoting business agility.
Am gestrigen Dienstag fand das Meeting der Deutschen ADF Community im CVC der Oracle Niederlassung in Berlin statt. Der Fokus lag dieses Mal weniger auf den technischen Feinheiten des Frameworks, sondern auf dem Thema „Vertrieb“. Aufgrund des Themenschwerpunkts waren neben altbekannten Teilnehmern auch viele neue Gesichter aus den Tiefen des Vertriebs der verschiedenen Partnerunternehmen anwesend. OPITZ CONSULTING war gleich mit drei Teilnehmern vertreten und gab somit schon alleine durch die Mannstärke ein eindeutiges Commitment zu ADF ab. Das bunte Programm ließ keine Wünsche offen.
Wie agil die ADF Community auf neue Anforderungen reagieren kann, zeigte bereits der erste Vortrag zum Thema „Enterprise Mobility“. Aufgrund von Schwierigkeiten mit der Flugverbindung konnte der Referent nicht physisch anwesend sein, so dass kurzerhand eine Web- und Telefonkonferenz aufgesetzt wurde. Die Runde war sich weitestgehend einig, dass mobile Lösungen im Enterprise-Bereich in Zukunft eine stärkere Rolle einnehmen werden und sieht ADF in diesem Zusammenhang durch das Mobile Application Framework (MAF) und den Zukauf von Bitzer gut aufgestellt. Diesem Trend folgend drehte sich auch der zweite Beitrag dieses Tages auf um das Thema MAF. Michael Krebs von esentri referierte dabei sehr bildlich über „Oracle MAF und die Positionierung einer mobilen Unternehmensstrategie“. Am Nachmittag folgten dann noch Vorträge zu „ADF im Kontext der Oracle Fusion Middleware“ (Ingo Prestel, Oracle), „Oracle ADF und Forms-Modernisierung“ (Andreas Gaede, PITSS).
Jochen Rieg von virtual7 moderierte eine interaktive Session zu „Oracle ADF als Basis für moderne Unternehmens-Anwendungen“. Dabei wurden von den Teilnehmern fachliche Einsatzszenarien, USPs von ADF, sowie eine Statistik zu Branchen in denen ADF Projekte bereits umgesetzt werden, erarbeitet. Es wurde in diesem Zusammenhang deutlich, dass derzeit die meisten Partnerunternehmen Projekte für Kunden im „public sector“ umsetzen. Da wir die Statistik selbst „gefälscht“ hatten gab es keinen Grund ihr in diesem Punkt nicht zu trauen. Neben den spannenden Sessions diskutierte die Runde sehr lebhaft und konstruktiv über mögliche Vertriebswege von ADF. Die Teilnehmer waren sich einig, dass die Technologie deutliche Vorteile im Vergleich zu anderen Frameworks aufweist, im Markt aber noch zu unbekannt sei. Die zahlreichen Aktivitäten der ADF Community werden in Zukunft sicher ihren Teil dazu beitragen, dies zu ändern. Erste Anzeichen sind in diesem Bereich schon wahrzunehmen. So wird beispielsweise bei der diesjährigen Konferenz der Deutschen Oracle Anwendergruppe zum ersten Mal ein eigener Slot für die ADF Community reserviert.
Alles in allem kann man wieder einmal von einem sehr gelungenen Treffen der ADF Community sprechen. Die thematische Ausrichtung auf das Thema „Vertrieb“ sorgte für interessante Diskussionen. Wir freuen uns, Teil dieser lebendigen Community zu sein und werden gerne am nächsten Community-Meeting teilnehmen.
|Die neuen Oracle 12c Versionen sind da!|
SOA Suite & BPM Suite Launch Events vom Oracle Platinum Partner OPITZ CONSULTING
23.10.14 Düsseldorf | 28.10.14 München
Sehr geehrte Damen und Herren,
die SOA Suite ist Oracle’s Lösung für Systemintegrationen jeglicher Art. Die BPM Suite bietet alles zur Prozessautomatisierung und zum Bau von Workflowlösungen mit BPMN 2.0.
Erleben Sie in einem komprimierten Abendprogramm in lockerer Atmosphäre bei Getränken, Snacks und einem anschließenden Abendessen, warum wir als Projekthaus die neuen 12c Versionen beider Suiten für einen großen Wurf halten.
Wir bleiben dabei marketingfrei, zeigen viele Live Demos und diskutieren in den Pausen gerne bis in beliebige Tiefen der neuen Produkte.
Es erwarten Sie diese Themen:
Details und Anmeldung
Wir freuen uns auf Ihren Besuch!
Last week the Oracle Fusion Middleware summer camps took place in Lisbon. More than 100 participants attended the event, learning much new stuff about new features and enhancements, arriving with the recently available FMW 12c release. In four parallel tracks the highlights of the new major release were presented to the attendees; hands-on labs allows to get a first impression regarding the new platform features and the markedly increased productivity delivered by the enhanced, consolidated tooling.
The four tracks had different focuses, regarding the new features of the 12c release of Oracle Middleware platform:
- SOA 12c – focusing on application integration, including Oracle Managed File Transfer (MFT), and fast data with Oracle Event Processing (OEP)
- BPM 12c – focusing on Business Process Management, the new enhanced Business Activity Monitoring (BAM) and Adaptive Case Management (ACM)
- SOA/BPM 12c (Fast track) – Combined track, covering the most important enhancements and concepts with reference to SOA and BPM 12c
- Mobile Application Framework (MAF) Hackathon – Development of mobile applications using the newly released MAF (formerly known as ADF mobile)
The main topics addressed by the new OFM 12c release are:
- Cloud integration
- Mobile integration
- Developer’s performance
- Industrial SOA
Integrating Cloud solutions in grown IT system landscapes is complex. With SOA Suite 12c, Oracle provides a coherent and simple approach for integrating enterprise applications with existing cloud solutions. Therefore new JCA-based cloud adapters, e..g. for integrating with Salesforce, as well as a Cloud SDK are available. Service Bus might be used in this context to care about transformation, routing and forms the backbone of a future-oriented, flexible as well as scalable cloud application architecture.
Mobile-enablement of enterprise applications is a key requirement and a necessity for application acceptance today. The new JCA REST adapter can be used to easily REST-enable existing applications. In combination with Oracle MAF and Service Bus, Oracle provides a complete Mobile Suite, where seamless development of new mobile innovations can be done.
To enhance development performance, the new SOA and BPM Quickinstalls are introduced. Using those allows the developers to have a complete SOA or BPM environment installed in 15 minutes (see the blog post of my colleague). Furthermore new debugging possibilities, different templating mechanisms (SOA project templates, Custom activity templates, BPEL subprocesses and Service Bus pipeline Templates) as well as JDeveloper as the single and only IDE deliver a maximum good development experience.
Industrializing SOA is a main goal, when starting with a SOA initiative: Transparent monitoring and management and a robust, scalable and performant platform are key to successfully implementing SOA-based applications and architectures. These points are addressed by the new OFM 12c release through the following features:
- Lazy Composite Loading – Composites will be loaded on demand and not at platform startup
- Modular Profiles – Different profiles provided, which enables only the features currently needed (e.g. only BPEL)
- Improved Error Hospital and Error Handling
- Optimized Dehydration behaviour
- Integrated Enterprise Scheduler (ESS)
Further main enhancements that where introduced regarding SOA and BPM Suite 12c were:
- Oracle BPM Suite 12c: Definition of Business Architecture, including definition of Key Performance Indicators (KPI) and Key Risk Indicators (KRI) to provide an integral overview from a high-level perspective; ACM enhancements in the direction of predictive analytics
- Oralce BAM 12c: Completly re-implemented in ADF, allows operational analytics based on the defined KPIs and KRIs
- Oracle MFT: Managed File Transfer solution for transferring big files from a specified source to a defined target; integration with SOA/BPM Suite 12c can be done by new JCA-based MFT adapters
Looking back, a great and very interesting week lays behind me, providing a bunch of new ideas and impressions on the new Fusion Middleware 12c release. I’m looking forward to use some of this great new stuff soon, in real world’s projects.
Special thanks to Jürgen Kress for the excellent organization of the event! I’m already looking forward for next SOA Community event…
If you write documents and get feedback from different persons on different versions it is a great pain to merge the documents and changes together. Microsoft Word has a functionality that works quite well. But the function to compare documents in Open Office Writer has never work for me the way I expected.
Fortunately OO stores documents in a zip file, containing xml files. The main content of the document is the file content.xml. After changing the extension of the OO Writer document to zip it is possible to open the file with the favorite zip application and extracting the content.xml file. If you do this for both versions you can compare the both files with your favorite text compare tool and you will see … hmmm yes… thousands of changes. This happens especially if the documents have been edited with different versions of Open Office or Libre Office. Most of the changes are not relevant for your comparison.
So we would like to eliminate the changes not interested in to get an overview of the real changes.
We open both versions of content.xml with Notepad++ and do a “Linarize XML” with XML Tools first on both files.
In the next step we replace these six regular expressions with an empty string. This is done recursively until no further replace is possible:
1 [a-zA-Z0-9\-]+:[a-zA-Z0-9\-]+="[^"]*" 2 <([a-zA-Z0-9\-]+:)?[a-zA-Z0-9\-]+\s*/> 3 <([a-zA-Z0-9\-]+:)?[a-zA-Z0-9\-]+\s*>\s*</([a-zA-Z0-9\-]+:)?[a-zA-Z0-9\-]+> 4 <text:changed\-region\s*>.*?<\/text:changed\-region> 5 <office:annotation\s*>.*?<\/office:annotation> 6 <text:bookmark-ref\s*>.*?<\/text:bookmark-ref>
Finally we use the “Pretty print (libxml)” function of XML Tools to get the XML files formatted. Now it is possible to compare the two files with tool for comparing text files and you will see the real text changes.
Key words: IT-Security, WebLogic Server, WebLogic Security Framework, Authorization, authorization process, Role Mapping, Roles, Adjudication Process, Security Service Provider Interfaces (SSPIs), Users, Groups, Principals and Subjects
We discussed about Authentication in Part 4 and 5; now let us focus on Authorization topic. Authorization is known as access control too and is used to clear main questions such as: “What can you access?”, “Who has access to a WebLogic resource?”, “Is access allowed?” and in general “Who can do what?“ In order to guarantee integrity, confidentiality (privacy), and availability of resources, WebLogic are restricted accesses to these resources. In other words, authorization process is responsible to grant access to specific resources based on an authenticated user’s privileges.
Authorization: What can you access?
After authentication one user, it is the first question that system has to answer: “What can you access?” In this sense, WebLogic Server has to clear, which resources are available for a particular user, that will be cleared by using the user’s security role and the security policy assigned to the requested WebLogic resource. A WebLogic resource is generally understood as a structured object used to represent an underlying WebLogic Server entity, which can be protected from unauthorized access using security roles and security policies. WebLogic resource implementations are available for:
- Administrative resources
- Application resources
- Common Object Model (COM) resources
- Enterprise Information System (EIS) resources
- Enterprise JavaBean (EJB) resources
- Java Database Connectivity (JDBC) resources
- Java Messaging Service (JMS) resources
- Java Naming and Directory Interface (JNDI) resources
- Server resources
- Web application resources
- Web service resources
- Work Context resources
The Authorization Process
I’m going to clear whole process in a top-down approach. First of all, we have to see what will be happen in Authorization Process? Figure 1 Authorization Process shows how WebLogic Security Framework communicated with a particular Security Provider and Authorization providers respectively.
Figure 1 Authorization Process
If a user want to use one protected resource, then WebLogic send a request to “Resource Container” that handles the type of WebLogic resource being requested receives the request (for example, the EJB container receives the request for an EJB resource). It forwards to “WebLogic Security Framework” and its request parameters, including information such as the subject of the request and the WebLogic resource being requested. The Role Mapping providers use the request parameters to compute a list of roles to which the subject making the request is entitled and passes the list of applicable roles back to the WebLogic Security Framework. On this information will be decided about authorization: e.g. PERMIT and/or DENY. WebLogic Server provides an auditing to collect, store and distribute information about requests and outcomes. It calls Adjudication. It can happened that for Authorization is defined multiple providers. For such cases is an Adjudication provider available. The WebLogic Security Framework delegates the job of merging any conflicts in the Access Decisions rendered by the Authorization providers to the Adjudication provider. It resolves the conflicts and sends a final decision (TRUE or FALSE) to WebLogic Security Framework.
WebLogic Security Framework
I have mentioned a bit about WebLogic Security Framework in Part 1 and 2. Figure 2 WebLogic Security Service Architecture shows a high-level view of the WebLogic Security Framework. The framework contains interfaces, classes, and exceptions in the weblogic.security.service package. The Framework provides a simplified application programming interface (API) that can be used by security and application developers to define security services. Within that context, the WebLogic Security Framework also acts as an intermediary between the WebLogic containers (Web and EJB), the Resource containers, and the security providers.
Figure 2 WebLogic Security Service Architecture
The Security Service Provider Interfaces (SSPIs) can be used by developers and third-party vendors to develop security providers for the WebLogic Server environment.
Figure 1 Authorization Process presents Security Provider as next module that provides security services to applications to protect WebLogic resources. A security provider consists of runtime classes and MBeans, which are created from SSPIs and/or Mbean types. Security providers are WebLogic security providers (provided with WebLogic Server) or custom security providers. You can use the security providers that are provided as part of the WebLogic Server product, purchase custom security providers from third-party security vendors, or develop your own custom security providers.
In order to complete authorization process, is Role Mapping within security provider necessary. Simple to say, a role mapper maps a valid token to a WebLogic user. Formerly that we focus on Roles, I would like to clarify a few more terms.
Users, Groups, Principals and Subjects
User is an entity that is authenticated in our security provider in last steps (See: Part 4 and 5 – Authentication Process). A user can be a person or a software entity or other instances of WebLogic Server. As a result of authentication, a user is assigned an identity, or principal. A principal is an identity assigned to a user or group as a result of authentication and can consist of any number of users and groups. Principals are typically stored within subjects. Both users and groups can be used as principals by WebLogic Server.
Groups are logically ordered sets of users. Usually, group members have something in common. For example, a company may separate its IT-Department into two groups, Admins and Developers. In this form, it will be possible to define different levels of access to WebLogic resources, depending on their group membership. Managing groups is more efficient than managing large numbers of users individually. For example, an administrator can specify permissions for several users at one time by placing the users in a group, assigning the group to a security role, and then associating the security role with a WebLogic resource via a security policy. All user names and groups must be unique within a security realm.
Role is a dynamically computed privilege that is granted to users or groups based on specific conditions. The difference between groups and roles is that a group is a static identity that a server administrator assigns, while membership in a role is dynamically calculated based on data such as user name, group membership, or the time of day. Security roles are granted to individual users or to groups, and multiple roles can be used to create security policies for a WebLogic resource. A security role is a privilege granted to users or groups based on specific conditions.
Like groups, security roles allow you to restrict access to WebLogic resources for several users at once. However, unlike groups, security roles:
- Are computed and granted to users or groups dynamically, based on conditions such as user name, group membership, or the time of day.
- Can be scoped to specific WebLogic resources within a single application in a WebLogic Server domain (unlike groups, which are always scoped to an entire WebLogic Server domain).
Granting a security role to a user or a group confers the defined access privileges to that user or group, as long as the user or group is “in” the security role. Multiple users or groups can be granted a single security role. It can be summarized as follows:
Groups are static and defined on Domain level (coarse granularity) and Roles are dynamic and defined on Resource level (fine granularity). Continued…
See too last parts of IT-Security and Oracle Fusion Middleware:
 Oracle® Fusion Middleware Understanding Security for Oracle WebLogic Server, 11g Release 1 (10.3.6), E13710-06
 Oracle® Fusion Middleware Securing Oracle WebLogic Server 11g Release 1 (10.3.6), E13707-06
 Oracle® Fusion Middleware Securing Oracle WebLogic Server 11g Release 1 (10.3.6), E13707-06