Planning Considerations

Conﬁguring HP DCE Cells

Integrating DCE Services with MC/ServiceGuard

While the replication mechanisms of the Security Service and the Naming Service differ in design and implementation, they share this master-slave approach. Therefore, while both services can be considered highly available for read operations, they do present a single point of failure for write operations.

The Time Service, on the other hand, does not present the same level of vulnerability. Most mission critical installations will conﬁgure more than the minimum necessary time servers with multiple time providers. This being the case, the loss of a single time server is usually not critical.

Installations should not establish an MC/ServiceGuard conﬁguration for the purpose of maintaining the Time Service alone.

DCE-based applications can also present a single point of failure, unless the developers provide for the replication of data and functions between multiple servers. Since replication is a complicated and complex process, many application designers may choose to depend on a “fail over” approach such as MC/ServiceGuard to provide availability, rather than develop and maintain their own replication mechanisms.

In summary, you only need to use MC/ServiceGuard to increase the availability of DCE Core Services and DCE-based services that are not replicated. In the case of the DCE Core services, these are the write functions provided by the DCE master Security and Naming replicas.

In your planning for MC/ServiceGuard, you must consider the following characteristics of DCE and DCE-based programs:

•The DCE runtime and daemons do not themselves support the concept of dynamic IP addresses.

•Normal DCE programming practice assumes that all IP addresses on the host should be used for endpoints for exported services.

The DCE runtime determines the available IP addresses on the node during the execution of any of the rpc_server_use_* routines. These routines are used in every DCE server to select the protocols over which the server will provide services. A side effect of this call is that the list of IP addresses supported by the node is established for use later when determining the binding vector. When this vector is obtained by a server main routine and registered in the endpoint map, the endpoint map will contain entries for every IP address identiﬁed earlier during the rpc_server_use_* call. In addition, should this binding vector be

Planning and Conﬁguring HP DCE 1.7

5-31

UX DCE Software specifications

HP UX DCE Software, or Hewlett-Packard UNIX Distributed Computing Environment, represents a significant tool in the realm of distributed system architecture. Designed primarily for enterprise environments, HP UX DCE enhances the reliability, scalability, and manageability of applications over diverse networked systems.

One of the main features of HP UX DCE is its ability to integrate various computing platforms, enabling seamless communication and resource sharing across distributed nodes. This facilitates the creation of complex applications that can operate on a multitude of systems, thus enhancing operational flexibility. DCE employs standardized interfaces, which means applications written for one platform can run on any other platform that supports DCE, promoting cross-platform compatibility.

In terms of technologies, HP UX DCE utilizes Remote Procedure Calls (RPC) as a core feature. This mechanism allows different applications to communicate and invoke procedures on remote systems as if they were local calls. Additionally, DCE includes a robust security model that incorporates Kerberos for authentication, ensuring that communication between nodes remains secure and protected against unauthorized access.

Another significant characteristic of HP UX DCE is its distributed file system, which allows for transparent file access across different machines. The DCE File System (DFS) provides a unified namespace and manages data replication and consistency across distributed storage resources. This reduces the complexity of data management and enhances data availability.

HP UX DCE also supports a variety of programming languages, making it accessible for developers accustomed to different coding environments. This versatility encourages widespread adoption and innovation, as developers can leverage existing skills to create distributed applications.

Furthermore, HP UX DCE is built for high availability, ensuring that critical applications remain responsive even in the face of hardware or network failures. Its inherent component redundancy and fault-tolerant architecture are designed to minimize downtime, which is essential for mission-critical applications in enterprise scenarios.

In conclusion, HP UX DCE Software provides a comprehensive framework for developing, deploying, and managing distributed applications. Its core features such as RPC support, a secure authentication mechanism, a robust file system, and cross-platform compatibility make it a vital resource for organizations aiming to leverage distributed computing effectively. As enterprises evolve, HP UX DCE stands out as an influential solution in the dynamic landscape of distributed environments.

HP UX DCE Software manual Planning Considerations

Models: UX DCE Software