openstack-manuals/doc/arch-design/hybrid/section_operational_conside...

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xml:id="arch-guide-hybrid-operational-considerations">
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<title>Operational considerations</title>
<para>Hybrid cloud deployments present complex operational
challenges. Differences between provider clouds can cause
incompatibilities with workloads or Cloud Management
Platforms (CMP). Cloud providers may also offer different levels of
integration with competing cloud offerings.</para>
<para>Monitoring is critical to maintaining a hybrid cloud, and it is
important to determine if a CMP supports
monitoring of all the clouds involved, or if compatible APIs
are available to be queried for necessary information.</para>
<section xml:id="agility">
<title>Agility</title>
<para>Hybrid clouds provide application
availability across different cloud environments and
technologies. This availability enables the deployment to
survive disaster in any single cloud environment.
Each cloud should provide the means to create instances quickly
in response to capacity issues or failure elsewhere in the hybrid
cloud.</para>
</section>
<section xml:id="application-readiness-hybrid">
<title>Application readiness</title>
<para>Enterprise workloads that depend on the
underlying infrastructure for availability are not designed to
run on OpenStack. If the application cannot
tolerate infrastructure failures, it is likely to require
significant operator intervention to recover. Applications for
hybrid clouds must be fault tolerant, with an SLA that is not tied
to the underlying infrastructure. Ideally, cloud applications should be
able to recover when entire racks and data centers experience an
outage.</para>
</section>
<section xml:id="upgrades">
<title>Upgrades</title>
<para>If a deployment includes a public cloud, predicting
upgrades may not be possible. Carefully examine provider SLAs.</para>
<note>
<para>At massive scale, even when
dealing with a cloud that offers an SLA with a high percentage
of uptime, workloads must be able to recover quickly.</para>
</note>
<para>When upgrading private cloud deployments, minimize disruption by
making incremental changes and providing a facility to either rollback
or continue to roll forward when using a continuous delivery
model.</para>
<para>You may need to coordinate CMP upgrades with hybrid cloud upgrades if
there are API changes.</para>
</section>
<section xml:id="network-operation-center-noc">
<title>Network Operation Center</title>
<para>Consider infrastructure control
when planning the Network Operation Center (NOC)
for a hybrid cloud environment. If a significant
portion of the cloud is on externally managed systems,
prepare for situations where it may not be possible to
make changes.
Additionally, providers may differ on how
infrastructure must be managed and exposed. This can lead to
delays in root cause analysis where each insists the blame
lies with the other provider.</para>
<para>Ensure that the network structure connects all clouds to form
integrated system, keeping in mind the state of handoffs.
These handoffs must both be as reliable as possible and
include as little latency as possible to ensure the best
performance of the overall system.</para>
</section>
<section xml:id="maintainability">
<title>Maintainability</title>
<para>Hybrid clouds rely on third party systems and processes. As a
result, it is not possible to guarantee
proper maintenance of the overall system. Instead, be prepared to
abandon workloads and recreate them in an improved state.</para>
</section>
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