Advanced High. Architecture.

Transcription

1 Advanced High Availability Architecture

2 Advanced High Availability Architecture WHITE PAPER Advanced High Availability Architecture Overview This document describes the ServiceNow Advanced High Availability architecture and explains how the ServiceNow service meets the most stringent customer requirements. ServiceNow provides a robust application platform service to support customer service automation, ITSM, workflow, and application integration requirements. This application platform service is provided through a Software as a Service (SaaS) model, which helps customers take advantage of this comprehensive software platform, 24x7 operations, and security monitoring. ServiceNow has developed its SaaS platform to address performance, availability, continuity of service, as well as confidentiality and integrity of the data and environment. ServiceNow Security Architecture ServiceNow is a cloud-based service platform designed to automate enterprise IT operations. The service is delivered through a SaaS model using a unique multi-instance architecture that provides all customers with dedicated applications and database. The services are hosted within ServiceNow data centers, and are accessible by customers through a web browser. The application is protected by firewalls, load balancers, intrusion prevention systems, and a segmented network architecture providing a protected production environment for each client. As part of the design, browser requests are sent to the DMZ within the primary geographic data center assigned to each customer. Once received, these requests pass through a pair of load balancers used to identify the application server responsible for processing the request. The request is assigned to a specific application instance operating inside a Java VirtualMachine and a session is established with the end user. The session state is maintained by the load balancers and the application server until the user s request has been handled and data has been stored or transmitted by the request. Data is sent to and stored on a dedicated relational database (MySQL) catalog preventing co-mingling of customer data between customers. SERVICENOW 3

3 WHITE PAPER Advanced High Availability Architecture Highly Available Architecture The data center and the cloud-based infrastructure have been designed with high availability as a core requirement. This design includes full redundancy and fault tolerance of electrical, cooling, network, security, and server infrastructure. At the heart of this architecture, each client instance is supported by multi-homed network configuration with multiple connections to the Internet. Redundant network, security, and server infrastructurecomponents are managed and maintained by ServiceNow, isolating the ServiceNow SaaS environment from the rest of the data center colocation environment. The deployed servers are enterprise-grade hardware with redundant hardware components - power and storage configurations to ensure the maximum uptime and availability of the ServiceNow services. Production application servers are load balanced for both availability and scalability reasons. Production database servers are replicated in near real-time to a mirrored data center within the same geographic region of Europe and North America. We leverage our high availability architecture in three ways: 1. In the event of the failure of one or more customer s infrastructure component, we will fail over the customer instances associated with the failed components over to the mirrored location 2. During our normal course of performing maintenance of infrastructure components, we will failover the customer instances associated with the infrastructure maintenance to their mirrored location and perform the maintenance on the vacated environment in order to maintain the highest level of security, availability, and scalability 3. During a large-scale outage, including, the complete loss of a data center, we will fail over the entire data center to its mirrored geographic data center Global Mirrored Data Centers North America: Culpeper, VA and San Jose, CA Europe: London, U.K. and Amsterdam, Netherlands *Canada: Montreal, QC and Toronto, ON *Switzerland: Zurich and Geneva *Australia: Brisbane, QLD and Sydney, NSW San Jose Montreal Toronto Culpeper, VA London Zurich Amsterdam Geneva Brisbane Sydney * Advanced high availability capabilities are anticipated in these datacenters in fourth quarter SERVICENOW

4 Advanced High Availability Architecture WHITE PAPER High Level Overview of HA Failover Process The HA failover process is comprised of six main steps which will be invoked through our cloud automation platform, once our crisis management team determines the failover is required, or scheduled maintenance activity is ready to be performed. High Level automated failover steps: 1. Verify replication is synchronized between both data centers 2. Stop all application nodes associated with the customer instance 3. Reverse roles for each database from read-only to read-write, and vice versa 4. Change the database pointer to the read-write database within the application nodes 5. Change the DNS associated with the customer instance TTL 6. Start all application nodes associated with the instance Backup and Recovery ServiceNow also maintains seven daily and three weekly backups on disk. The backup data never leaves the ServiceNow data centers. Backups are taken in both data centers on all customer instances including sub-production and production instances. It is important to note the primary recovery method of a customer production instance is to use the High Availability replica. The backups are used as a secondary recovery mechanism. SERVICENOW 5

5 WHITE PAPER Advanced High Availability Architecture Critical Resources Critical system resources including DNS, ServiceNow s instance management (HI), and ServiceNow s cloud automation instance are operated in high availability configurations in a minimum of two data centers, not relying on any of ServiceNow s corporate infrastructure. Moreover, development systems used for source code control and the software build process are also hosted at the production data centers to ensure the highest continuity for our developers. This enables developers to support and continue developing the application without requiring physical access to ServiceNow offices. Technical personnel required to monitor and maintain the ServiceNow platform operate on a 7x24 basis and are located in two disparate geographic locations, the U.K. and the U.S. We rotate our operations, infrastructure, and technical support personnel daily, so in the event of a region wide disaster, the personnel in the opposite geographic region will assume 7x24 responsibilities. Summary Our Advanced High Availability architecture is designed to world-class availability standards and for achieving high security and data isolation through our unique multiinstance architecture. This high availability architecture not only accommodates for a disaster, but the same high availability failover process is used for preventative maintenance, eliminating the need for a yearly disaster recovery test, and creating a practiced failover event during performance of normal maintenance. 6 SERVICENOW

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