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- Moved RST guide to the arch-design folder - Deleted XML files - Updated scripts Change-Id: Id0e38a9cada9dd75cb9c8f3bd2d88ce2f4fd3eac Implements: blueprint archguide-mitaka-rst
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2.3 KiB
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69 lines
2.3 KiB
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==========================
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Operational considerations
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==========================
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There are a number of operational considerations that affect the design
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of compute-focused OpenStack clouds, including:
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* Enforcing strict API availability requirements
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* Understanding and dealing with failure scenarios
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* Managing host maintenance schedules
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Service-level agreements (SLAs) are contractual obligations that ensure
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the availability of a service. When designing an OpenStack cloud,
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factoring in promises of availability implies a certain level of
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redundancy and resiliency.
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Monitoring
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~~~~~~~~~~
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OpenStack clouds require appropriate monitoring platforms to catch and
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manage errors.
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.. note::
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We recommend leveraging existing monitoring systems to see if they
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are able to effectively monitor an OpenStack environment.
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Specific meters that are critically important to capture include:
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* Image disk utilization
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* Response time to the Compute API
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Capacity planning
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~~~~~~~~~~~~~~~~~
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Adding extra capacity to an OpenStack cloud is a horizontally scaling
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process.
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We recommend similar (or the same) CPUs when adding extra nodes to the
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environment. This reduces the chance of breaking live-migration features
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if they are present. Scaling out hypervisor hosts also has a direct
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effect on network and other data center resources. We recommend you
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factor in this increase when reaching rack capacity or when requiring
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extra network switches.
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Changing the internal components of a Compute host to account for
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increases in demand is a process known as vertical scaling. Swapping a
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CPU for one with more cores, or increasing the memory in a server, can
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help add extra capacity for running applications.
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Another option is to assess the average workloads and increase the
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number of instances that can run within the compute environment by
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adjusting the overcommit ratio.
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.. note::
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It is important to remember that changing the CPU overcommit ratio
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can have a detrimental effect and cause a potential increase in a
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noisy neighbor.
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The added risk of increasing the overcommit ratio is that more instances
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fail when a compute host fails. We do not recommend that you increase
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the CPU overcommit ratio in compute-focused OpenStack design
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architecture, as it can increase the potential for noisy neighbor
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issues.
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