VERITAS Cluster Server Traffic Director Option. Product Overview

Transcription

1 VERITAS Cluster Server Traffic Director Option Product Overview V E R I T A S W H I T E P A P E R

2 Table of Contents Traffic Director Option for VERITAS Cluster Server Overview Availability Through Scalability Traffic Director Option for VERITAS Cluster Server How the Traffic Director Option for VERITAS Cluster Server Works Traffic Direction/Load Balancing Alternatives Persistent Connections Traffic Director Option for VERITAS Cluster Server Administration Platform and Protocol Support

3 Traffic Director Option for VERITAS Cluster Server Available in Q Optional for the VERITAS Cluster Server product Provides traffic balancing for users needing highly scalable clusters Traffic Director servers will support Sun Solaris (support for additional hardware platforms is planned) Backend servers (receiving the load balanced traffic) can be of any platform Linux, UNIX or Windows Availability Through Scalability The increasing need for high availability for applications and servers in today s data centers, as well as the rapid growth of the Internet and e-commerce, is placing growing performance demands on applications and servers. The increasing volume of network traffic can overwhelm even the largest of servers, causing them to appear slow or fail altogether. Customers who expect Web or application servers to be available all of the time perceive slow performance to be the same as lack of availability. So, whereas ensuring that applications and data are available is critical, ensuring top performance is equally important to ensuring a pervasive HA environment. Load balancing, or traffic direction, is the process of distributing client network connections to share the traffic among several servers. By scaling the number of servers able to process requests and then balancing traffic between those servers, administrators can ensure that performance keeps up with demand. To the customer requesting information from a Web site or data from an application, the backend traffic distribution process is completely transparent. The Traffic Director Option for VERITAS Cluster Server VERITAS Cluster Server is a comprehensive, heterogeneous clustering solution that provides high availability for data and applications by managing planned and unplanned downtime. Historically, Cluster Server has provided availability through application failover. When a server or other resource in a Cluster Server cluster experiences some failure or problem, VERITAS Cluster Server will fail over applications and services running on the node experiencing the problem to other, healthy nodes in the cluster. Through this failover, Cluster Server keeps applications and services highly available. Traffic Director is a new option for VERITAS Cluster Server that will be available in Q The Traffic Director option provides availability through scalability and traffic load balancing by directing TCP/IP and UDP/IP traffic to multiple backend servers. As the demand on applications or a Web site increases, additional servers (virtually an unlimited number with Traffic Director) can be added to handle the additional requests. To ensure optimal performance, several traffic direction policies are available to route traffic and load balance across the backend servers. VERITAS Cluster Server - Traffic Director Option Page 1

4 How the Traffic Director Option for VERITAS Cluster Server Works In a Traffic Director cluster, load-balancing or Traffic Director servers distribute client network requests among multiple servers in a cluster so the load imposed by client requests is shared. A pair of Traffic Director servers may have one or more domains and each domain may have multiple virtual IP addresses. Each virtual IP address is available only on one of the Traffic Director servers at a time and is failed over to the other Traffic Director server when necessary. The TCP and UDP requests go to the virtual IP address on the Traffic Director server, where requests are load-balanced to one or more backend servers that will satisfy requests, as defined in the traffic direction policy. No additional software is needed on the backend servers. Traffic Director can handle multiple protocols, including HTTP, FTP, Telnet, SSL, POP3, SMTP, IMPA and streaming media. Figure 1: The Traffic Director option for VERITAS Cluster Server can load-balance requests to an unlimited number of backend servers, enabling administrators to scale applications and ensure performance as demand increases. The Traffic Director configuration is divided into domains. A domain contains one or more virtual IP addresses that clients communicate with when requesting information or data from Web pages or applications. There is no limit to the number of virtual IP addresses or servers that can be added to a domain. When demand increases, additional backend servers can be added easily to the Traffic Director for Cluster Server to satisfy the additional demand. To ensure high availability of Traffic Director itself, Traffic Director servers are configured as two-node, failover clusters. If one of the nodes running Traffic Director fails, the second can continue to direct traffic to backend servers. The Traffic Director cluster can run in active/passive mode, in which one of the cluster nodes acts as a standby for the other, or can run in active/active mode, in which the two nodes both act as standby servers for the other. A unique feature of Traffic Director is its ability to failover open connections. If a Traffic Director node fails as it is directing traffic, this feature allows client connections to resume operations from where they paused when the node faulted. Traffic Director is able to do this because both nodes in the Traffic Director cluster continuously share state information with each other, so either can pick up traffic direction responsibilities from the other at any time even for open connections. If a backend server fails, Traffic Director simply removes it from the list of servers available to accept requests. When the backend server is repaired and comes back online, Traffic Director allows it to re-enter the server group and start accepting requests again. Page 2 VERITAS Cluster Server - Traffic Director Option

5 Traffic Direction/Load Balancing Alternatives The VERITAS Cluster Server administrator can choose from several traffic direction alternatives with the Traffic Director option for Cluster Server. Alternatives include: IP packet direction This rule designates connections to be directed based on the virtual IP address. For example, all requests going to the virtual IP address for are directed to servers 1 10, whereas requests going to the virtual IP address for are directed to servers Destination TCP/UDP port direction This alternative allows traffic to be directed based on the destination TCP/UDP port (e.g., Web servers running on port 80, telenet running on port 23, etc.). Protocol content direction This rule enables traffic to be directed based on the type of content. For example, music MP3 files, graphic GIF and JPEG files and text-based HTML files can be grouped on separate servers and traffic directed between the server groups. The policies above specify how incoming requests are handled. To direct requests to backend servers, Traffic Director provides a number of server selection algorithms. Supported algorithms include: Round robin Sequentially selects servers in a group to evenly distribute traffic across servers Weighted round robin Each server in the group is assigned a value that indicates its processing capacity. Servers with the greatest processing capacity are given more traffic than servers with lesser processing capacity Least connections Directs traffic to the server with the least number of active connections. Persistent Connections For many applications, such as shopping carts on Internet sites it is important for security and reliability reasons that once a connection is established between a client and backend server, the connection remain intact for the duration of the transaction. For example, when a user purchases a book from a Web site, all requests related to that purchase (i.e., forms, credit card information, shipping information, etc.) need to be directed to the same backend server. Traffic Director for Cluster Server provides several mechanisms to ensure persistent connections. Connections can be established based on IP bindings or cookies. The Secure Socket Layer (SSL) can be used to establish secure, encrypted connections between clients and servers. VERITAS Cluster Server - Traffic Director Option Page 3

6 Traffic Director Option for VERITAS Cluster Server Administration To allow monitoring and administration of Traffic Director (e.g., add or delete virtual IP addresses, change traffic policies, etc.), it comes with a command-line interface (CLI) and a Web-based GUI. The CLI can be used interactively or through scripts to automate administrative tasks. The Web-based GUI is useful because it provides an easy-to-use interface which can be accessed from anywhere with no special software required. An important part of ensuring overall availability is being able to manage multiple clusters and clustered applications from a unified console. To provide unified management of a high availability environment, the Traffic Director GUI will be integrated with the VERITAS Cluster Server Web GUI and also the VERITAS Global Cluster Manager Web GUI. This allow consolidated management of all VERITAS clusters failover clusters and scalable load-balanced clusters from a single, unified console. Figure 2: The Traffic Director option for VERITAS Cluster Server Web GUI makes it easy to monitor and administer Traffic Director. Page 4 VERITAS Cluster Server - Traffic Director Option

7 Platform and Protocol Support Traffic Director option for VERITAS Cluster Server servers: Solaris 2.7, 8, 9 Additional platforms supported in the future Backend servers: Linux UNIX Windows Protocol support: HTTP SMTP POP3 FTP Telnet SSL RSTP MP3 VERITAS Cluster Server - Traffic Director Option Page 5

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