Dynamically updating distributed software: supporting change in uncertain and mistrustful environments

Segal, Mark E.; Frieder, Ophir

doi:10.1109/icsm.1989.65219

Cited by 15 publications

(4 citation statements)

References 11 publications

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“…Mixed-version races can be prevented by completing the server-side upgrade before upgrading the clients in a multi-tiered system [36], to prevent the new version from calling into the old version. These approaches are infeasible in distributed systems that communicate across multiple administrative domains, with no central upgrade coordination.…”

Section: The Many Sources Of Inconsistency In Cloud Upgradesmentioning

confidence: 99%

“…In addition, certain inconsistencies manifest only at deployment time (e.g., as in the case of mixed-version races) and are difficult to detect during testing. Solutions that have been proposed for maintaining cross-tier consistency include using a single language for all three tiers, to avoid impedance mismatch during development [39], and forcing the upgrade to begin at the storage tier, continue with the compute tier, and finally the client, to avoid deployment-time inconsistencies [36]. Another solution is to make mixed-version interaction explicit in the implementation, which will make application upgrades safe by construction.…”

Section: Maintaining Cross-datacenter Consistencymentioning

confidence: 99%

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Cloud software upgrades: Challenges and opportunities

Neamtiu

Dumitraş

2011

2011 International Workshop on the Maintenance and Evolution of Service-Oriented and Cloud-Based Systems

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The fast evolution pace for cloud computing software is on a collision course with our growing reliance on cloud computing. On one hand, cloud software must have the agility to evolve rapidly, in order to remain competitive; on the other hand, more and more critical services become dependent on the cloud and demand high availability through firm Service Level Agreements (SLAs) for cloud infrastructures. This race between the needs to increase both the cloud upgrade frequency and the service availability is unsustainable. In this paper we highlight challenges and opportunities for upgrades in the cloud. We survey the release histories of several cloud applications to analyze their evolution pace, and we discuss the shortcomings with current cloud upgrade mechanisms. We outline several solutions for sustaining this evolution while improving availability, by focusing on the novel characteristics of cloud computing. By discussing several promising directions for realizing this vision, we propose a research agenda for the future of software upgrades in the cloud.

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Section: The Many Sources Of Inconsistency In Cloud Upgradesmentioning

confidence: 99%

Section: Maintaining Cross-datacenter Consistencymentioning

confidence: 99%

Cloud software upgrades: Challenges and opportunities

Neamtiu

Dumitraş

2011

2011 International Workshop on the Maintenance and Evolution of Service-Oriented and Cloud-Based Systems

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“…Previous research advocates coordinating the upgrade operations [14,26,29], to prevent the new version from calling into the old version, simulating the interfaces of past and future versions during the upgrade [1] or performing upgrades atomically, end-to-end [10], to avoid mixed versions altogether. These approaches are infeasible in large-scale distributed systems that span multiple administrative domains (e.g., by relying on client-side code or on cloud-computing resources), where an online upgrade's administrator does not control all the tiers and cannot coordinate their upgrades.…”

Section: Introductionmentioning

confidence: 99%

“…In the absence of fault-tolerance mechanisms or control APIs, the PODUS system establishes simple rules for coordinating a distributed-system upgrade, such as upgrading servers before their clients [26]. This approach can be extended to systems that communicate across multiple administrative domains using remote procedure calls (RPC), which consist of synchronous request-and-reply message exchanges.…”

Section: Introductionmentioning

confidence: 99%

To upgrade or not to upgrade

Dumitraş

Narasimhan

Tilevich

2010

Proceedings of the ACM International Conference on Object Oriented Programming Systems Languages and Applications

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Online software upgrades are often plagued by runtime behaviors that are poorly understood and difficult to ascertain. For example, the interactions among multiple versions of the software expose the system to race conditions that can introduce latent errors or data corruption. Moreover, industry trends suggest that online upgrades are currently needed in large-scale enterprise systems, which often span multiple administrative domains (e.g., Web 2.0 applications that rely on AJAX client-side code or systems that lease cloudcomputing resources). In such systems, the enterprise does not control all the tiers of the system and cannot coordinate the upgrade process, making existing techniques inadequate to prevent mixed-version races. In this paper, we present an analytical framework for impact assessment, which allows system administrators to directly compare the risk of following an online-upgrade plan with the risk of delaying or canceling the upgrade. We also describe an executable model that implements our formal impact assessment and enables a systematic approach for deciding whether an online upgrade is appropriate. Our model provides a method of last resort for avoiding undesirable program behaviors, in situations where mixed-version races cannot be avoided through other technical means.

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