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- Committer: Frank Mueller
- Date: 2014-04-16 10:14:27 UTC
- Revision ID: frank.mueller@canonical.com-20140416101427-63g1yxjlqusfhgyx
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- Admin/Scaling-OpenStack.md
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- Install/Installing-Ceph.md
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Admin/Scaling-OpenStack.md
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Title: Scaling - OpenStack
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Status: In Progress
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# Scaling - OpenStack
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## Introduction
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Whereas traditional applications required larger hardware to scale ("vertical scaling"),
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cloud-based applications typically request more, discrete hardware ("horizontal scaling").
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If your cloud is successful, eventually you must add resources to meet the increasing
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demand.
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To suit the cloud paradigm, OpenStack itself is designed to be horizontally scalable.
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Rather than switching to larger servers, you procure more servers and simply install
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identically configured services. Ideally, you scale out and load balance among groups
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of functionally identical services.
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But to scale the services running on OpenStack sometimes even OpenStack itself has to
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be scaled. This means nodes for computing or storage have to be added.
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## Scope
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**TODO**
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## Nova
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### Analyzis
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To list the hosts and the nova-related services that run on them call
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```
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$ nova host-list
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+------------------+-------------+----------+
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| host_name | service | zone |
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+------------------+-------------+----------+
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| devstack-grizzly | conductor | internal |
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| devstack-grizzly | compute | nova |
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| devstack-grizzly | cert | internal |
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| devstack-grizzly | network | internal |
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| devstack-grizzly | scheduler | internal |
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| devstack-grizzly | consoleauth | internal |
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+------------------+-------------+----------+
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```
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To get a summary of resource usage of all of the instances running on the host call
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```
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$ nova host-describe devstack-grizzly
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+------------------+----------------------------------+-----+-----------+---------+
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| HOST | PROJECT | cpu | memory_mb | disk_gb |
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+------------------+----------------------------------+-----+-----------+---------+
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| devstack-grizzly | (total) | 2 | 4003 | 157 |
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| devstack-grizzly | (used_now) | 3 | 5120 | 40 |
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| devstack-grizzly | (used_max) | 3 | 4608 | 40 |
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| devstack-grizzly | b70d90d65e464582b6b2161cf3603ced | 1 | 512 | 0 |
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| devstack-grizzly | 66265572db174a7aa66eba661f58eb9e | 2 | 4096 | 40 |
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+------------------+----------------------------------+-----+-----------+---------+
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```
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These information help you understand how this host is used.
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- The `cpu` column shows the sum of the virtual CPUs for instances running on the host.
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- The `memory_mb` column shows the sum of the memory (in MB) allocated to the instances
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that run on the hosts.
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- The `disk_gb` column shows the sum of the root and ephemeral disk sizes (in GB) of
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the instances that run on the hosts.
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- The `used_now` row shows the sum of the resources allocated to the instances that run
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on the host plus the resources allocated to the virtual machine of the host itself.
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- The `used_max` row shows the sum of the resources allocated to the instances that run
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on the host.
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**Note:** These values are computed by using only information about the flavors of the
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instances that run on the hosts. This command does not query the CPU usage, memory usage,
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or hard disk usage of the physical host.
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Now you an retrieve the CPU, memory, I/O, and network statistics for an instance. First
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list all instances.
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```
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$ nova list
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+--------------------------------------+----------------------+--------+------------+-------------+------------------+
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| ID | Name | Status | Task State | Power State | Networks |
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+--------------------------------------+----------------------+--------+------------+-------------+------------------+
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| 84c6e57d-a6b1-44b6-81eb-fcb36afd31b5 | myCirrosServer | ACTIVE | None | Running | private=10.0.0.3 |
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| 8a99547e-7385-4ad1-ae50-4ecfaaad5f42 | myInstanceFromVolume | ACTIVE | None | Running | private=10.0.0.4 |
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+--------------------------------------+----------------------+--------+------------+-------------+------------------+
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```
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Then, get diagnostic statistics:
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```
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$ nova diagnostics myCirrosServer
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+------------------+----------------+
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| Property | Value |
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+------------------+----------------+
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| vnet1_rx | 1210744 |
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| cpu0_time | 19624610000000 |
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| vda_read | 0 |
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| vda_write | 0 |
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| vda_write_req | 0 |
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| vnet1_tx | 863734 |
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| vnet1_tx_errors | 0 |
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| vnet1_rx_drop | 0 |
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| vnet1_tx_packets | 3855 |
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| vnet1_tx_drop | 0 |
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| vnet1_rx_errors | 0 |
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| memory | 2097152 |
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| vnet1_rx_packets | 5485 |
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| vda_read_req | 0 |
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| vda_errors | -1 |
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+------------------+----------------+
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```
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Finally you can get summary statistics for each tenant.
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```
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$ nova usage-list
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Usage from 2013-06-25 to 2013-07-24:
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+----------------------------------+-----------+--------------+-----------+---------------+
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| Tenant ID | Instances | RAM MB-Hours | CPU Hours | Disk GB-Hours |
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+----------------------------------+-----------+--------------+-----------+---------------+
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| b70d90d65e464582b6b2161cf3603ced | 1 | 344064.44 | 672.00 | 0.00 |
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| 66265572db174a7aa66eba661f58eb9e | 3 | 671626.76 | 327.94 | 6558.86 |
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+----------------------------------+-----------+--------------+-----------+---------------+
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```
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**TODO** How to interpret this information to know when to scale?
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### Scaling
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Adding compute nodes is straightforward. They are easily picked up by the existing
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installation. Simply call
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```
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juju add-unit nova-compute
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```
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## Cinder
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**TODO**
Loggerhead is a web-based interface for Breezy
Version: 2.0.1