[arch-design] Update compute resource information

1. Remove duplicated content
2. Add compute resource design information

Change-Id: Id3fdea2220fafe8728a8cb9e03c541f3953acb01
Partial-Bug: #1548184
Implements: blueprint archguide-mitaka-reorg

doc/arch-design-draft/source/capacity-planning-scaling.rst

@@ -191,12 +191,23 @@ Network
 ~~~~~~~
 .. TODO(unassigned): consolidate and update existing network sub-chapters.
 
+Compute resource design
+~~~~~~~~~~~~~~~~~~~~~~~
 
-Compute
+When designing compute resource pools, consider the number of processors,
-~~~~~~~
+amount of memory, and the quantity of storage required for each hypervisor.
-A relationship exists between the size of the compute environment and
+
-the supporting OpenStack infrastructure controller nodes requiring
+Consider whether compute resources will be provided in a single pool or in
-support.
+multiple pools. In most cases, multiple pools of resources can be allocated
+and addressed on demand, commonly referred to as bin packing.
+
+In a bin packing design, each independent resource pool provides service
+for specific flavors. Since instances are scheduled onto compute hypervisors,
+each independent node's resources will be allocated to efficiently use the
+available hardware. Bin packing also requires a common hardware design,
+with all hardware nodes within a compute resource pool sharing a common
+processor, memory, and storage layout. This makes it easier to deploy,
+support, and maintain nodes throughout their lifecycle.
 
 Increasing the size of the supporting compute environment increases the
 network traffic and messages, adding load to the controller or
@@ -213,15 +224,34 @@ It is necessary to add rack capacity or network switches as scaling out
 compute hosts directly affects network and data center resources.
 
 Compute host components can also be upgraded to account for increases in
-demand. This is also known as vertical scaling. Upgrading CPUs with more
+demand, known as vertical scaling. Upgrading CPUs with more
 cores, or increasing the overall server memory, can add extra needed
 capacity depending on whether the running applications are more CPU
 intensive or memory intensive.
 
+When selecting a processor, compare features and performance
+characteristics. Some processors include features specific to
+virtualized compute hosts, such as hardware-assisted virtualization, and
+technology related to memory paging (also known as EPT shadowing). These
+types of features can have a significant impact on the performance of
+your virtual machine.
+
+The number of processor cores and threads impacts the number of worker
+threads which can be run on a resource node. Design decisions must
+relate directly to the service being run on it, as well as provide a
+balanced infrastructure for all services.
+
 Another option is to assess the average workloads and increase the
 number of instances that can run within the compute environment by
 adjusting the overcommit ratio.
 
+An overcommit ratio is the ratio of available virtual resources to
+available physical resources. This ratio is configurable for CPU and
+memory. The default CPU overcommit ratio is 16:1, and the default memory
+overcommit ratio is 1.5:1. Determining the tuning of the overcommit
+ratios during the design phase is important as it has a direct impact on
+the hardware layout of your compute nodes.
+
 .. note::
 
    Changing the CPU overcommit ratio can have a detrimental effect
@@ -235,10 +265,20 @@ additional block storage nodes. Upgrading directly attached storage
 installed in compute hosts, and adding capacity to the shared storage
 for additional ephemeral storage to instances, may be necessary.
 
-For a deeper discussion on many of these topics, refer to the `OpenStack
+Consider the compute requirements of non-hypervisor nodes (also referred to as
-Operations Guide <http://docs.openstack.org/ops>`_.
+resource nodes). This includes controller, object storage, and block storage
+nodes, and networking services.
 
+The ability to add compute resource pools for unpredictable workloads should
+be considered. In some cases, the demand for certain instance types or flavors
+may not justify individual hardware design. Allocate hardware designs that are
+capable of servicing the most common instance requests. Adding hardware to the
+overall architecture can be done later.
+
+For more information on these topics, refer to the `OpenStack
+Operations Guide <http://docs.openstack.org/ops>`_.
 
 Control plane API services and Horizon
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-.. TODO(unassigned): consolidate existing control plane sub-chapters.
+
+.. No existing control plane sub-chapters in the current guide.

doc/arch-design-draft/source/index.rst

@@ -23,7 +23,6 @@ Contents
    :maxdepth: 2
 
    common/conventions.rst
-
    introduction.rst
    identifying-stakeholders.rst
    functional-requirements.rst
@@ -34,9 +33,7 @@ Contents
    security-requirements.rst
    legal-requirements.rst
    example-architectures.rst
-
    common/app_support.rst
-
    common/glossary.rst
 
 Search in this guide

doc/arch-design-draft/source/operator-requirements-capacity-planning.rst

@@ -1,61 +0,0 @@
-=================
-Capacity planning
-=================
-
-An important consideration in running a cloud over time is projecting growth
-and utilization trends in order to plan capital expenditures for the short and
-long term. Gather utilization meters for compute, network, and storage, along
-with historical records of these meters. While securing major anchor tenants
-can lead to rapid jumps in the utilization rates of all resources, the steady
-adoption of the cloud inside an organization or by consumers in a public
-offering also creates a steady trend of increased utilization.
-
-Capacity constraints for a general purpose cloud environment include:
-
-* Compute limits
-* Storage limits
-
-A relationship exists between the size of the compute environment and
-the supporting OpenStack infrastructure controller nodes requiring
-support.
-
-Increasing the size of the supporting compute environment increases the
-network traffic and messages, adding load to the controller or
-networking nodes. Effective monitoring of the environment will help with
-capacity decisions on scaling.
-
-Compute nodes automatically attach to OpenStack clouds, resulting in a
-horizontally scaling process when adding extra compute capacity to an
-OpenStack cloud. Additional processes are required to place nodes into
-appropriate availability zones and host aggregates. When adding
-additional compute nodes to environments, ensure identical or functional
-compatible CPUs are used, otherwise live migration features will break.
-It is necessary to add rack capacity or network switches as scaling out
-compute hosts directly affects network and datacenter resources.
-
-Compute host components can also be upgraded to account for increases in
-demand; this is known as vertical scaling. Upgrading CPUs with more
-cores, or increasing the overall server memory, can add extra needed
-capacity depending on whether the running applications are more CPU
-intensive or memory intensive.
-
-Another option is to assess the average workloads and increase the
-number of instances that can run within the compute environment by
-adjusting the overcommit ratio.
-
-.. note::
-
-   It is important to remember that changing the CPU overcommit ratio
-   can have a detrimental effect and cause a potential increase in a
-   noisy neighbor.
-
-Insufficient disk capacity could also have a negative effect on overall
-performance including CPU and memory usage. Depending on the back-end
-architecture of the OpenStack Block Storage layer, capacity includes
-adding disk shelves to enterprise storage systems or installing
-additional block storage nodes. Upgrading directly attached storage
-installed in compute hosts, and adding capacity to the shared storage
-for additional ephemeral storage to instances, may be necessary.
-
-For a deeper discussion on many of these topics, refer to the `OpenStack
-Operations Guide <http://docs.openstack.org/ops>`_.

doc/arch-design-draft/source/operator-requirements.rst

@@ -11,7 +11,6 @@ Operator requirements
    operator-requirements-licensing.rst
    operator-requirements-support-maintenance.rst
    operator-requirements-ops-access.rst
-   operator-requirements-capacity-planning.rst
    operator-requirements-quota-management.rst
    operator-requirements-policy-management.rst
    operator-requirements-hardware-selection.rst