229 lines
6.6 KiB
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229 lines
6.6 KiB
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========================
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Magnum Cluster Stats API
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========================
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Launchpad blueprint:
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https://blueprints.launchpad.net/magnum/+spec/magnum-stats-api
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This proposal is to add a new Magnum statistics API to provide useful metrics
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to OpenStack administrators/service providers as well as users.
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Problem Description
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-------------------
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Currently there is no magnum API to get usage metrics. This specification
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document proposes to add a new stats endpoint to Magnum API. The proposed
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stats endpoint will provide useful metrics such as overall current usage info
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to OpenStack service providers and also non-admin tenants will be able to
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fetch tenant scoped statistics.
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Use Cases
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---------
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Below given are some of the use cases that can be addressed by implementing
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stats API for Magnum:
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1. A Magnum tenant with admin role would like to get the total number of
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active clusters, nodes, floating IPs and Cinder volumes for all active
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tenants.
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2. A Magnum tenant with admin role would like to get the total number of
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active clusters, nodes, floating IPs and Cinder volumes for a specific
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tenant.
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3. A Magnum tenant without admin role can get the total number of active
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clusters, nodes, floating IPs and Cinder volumes scoped to that tenant.
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4. A Magnum tenant would like to discover the sum of allocated server capacity
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for a given cluster (in terms of aggregate vcpu, memory, local storage, and
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cinder volume storage).
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5. A Magnum tenant with admin role would like to discover the aggregate server
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capacity (in terms of aggregate vcpu, memory, local storage, and cinder
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volume storage) allocated by all clusters belonging to a specific tenant or
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all the tenants.
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Please note that this is not an exhaustive list of use cases and additional
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specs will be proposed based on the community needs.
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Proposed Changes
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----------------
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The proposed change is to add a new '/stats' REST API endpoint to Magnum
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service that will provide total number of clusters, nodes, floating IPs,
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Cinder volumes and also a summary view of server capacity (in terms of
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aggregate vcpu, memory, local storage, and cinder volume storage) allocated
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to a cluster, or to all the clusters owned by the given tenant or all the
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tenants.
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1. Add an API that returns total number of clusters, nodes, floating IPs, and
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Cinder volumes of all tenants.
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2. Add an API that returns total number of clusters, nodes, floating IPs, and
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Cinder volumes of a specific tenant.
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3. Add an API that returns aggregate vcpu, memory, local storage, and cinder
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volume storage for the given cluster.
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4. Add an API that returns aggregate vcpu, memory, local storage, and cinder
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volume storage allocated by all clusters belonging to a specific tenant.
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5. Update policy.json file to enable access to '/stats' endpoint to owner and
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admin (using a policy rule admin_or_owner).
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In the initial implementation stats data will be aggregated from Magnum DB
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and/or from other OpenStack services on demand. There will be some interaction
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between the conductor and the drivers through an interface. If needed, this
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on-demand stats aggregation implementation can be updated in future without
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affecting the REST API behavior. For example, if the proposed on-demand data
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aggregation is not responsive, Magnum conductor may need to collect the stats
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periodically and save in the Magnum DB.
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Initial work in progress review [2].
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Alternatives
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------------
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Without proposed stats endpoint, an administrator could use OpenStack clients
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to get some basic statistics such as server count, volume count etc. by
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relying on the Magnum naming convention. For example, to get nova instance
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count:
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nova list | grep -e "kube-" -e "swarm-" -e "mesos-" | wc
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For the number of cinder volumes:
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cinder list | grep "docker_volume" | wc -l
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For float IPs count:
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openstack ip floating list -f value|wc -l
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For clusters count:
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magnum cluster-list | grep "CREATE_COMPLETE" | wc -l
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Data model impact
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-----------------
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None, because data will be aggregated and summarized at the time of each stats
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API request, so no stats need to be persisted in the data store.
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REST API impact
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---------------
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Add a new REST endpoint '/stats' as shown below:
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A GET request with admin role to '/stats?type=cluster' will return the total
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clusters, nodes, floating IPs and Cinder volumes for all active tenants.
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A GET request without admin role to '/stats?type=cluster' will return the
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total clusters, nodes, floating IPs and Cinder volumes for the current tenant.
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A GET request with admin role to '/stats?type=cluster&tenant=<tenant-id>' will
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return the total clusters, nodes, floating IPs and Cinder volumes for the
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given tenant.
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A GET request to '/stats?type=cluster&tenant=<tenant-id>' without admin role
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will result in HTTP status code 403 (Permission denied) if the requester
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tenant-id does not match the tenant-id provided in the URI. If it matches,
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stats will be scoped to the requested tenant.
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Other Implementation Option
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---------------------------
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Existing /cluster API can be updated to include stats info as shown below:
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A 'GET' request with admin role to '/cluster/stats' will return total active
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clusters and nodes across all the tenants.
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A 'GET' request to '/cluster/stats/<tenant-id>' will return total clusters and
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nodes for the given tenant.
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A 'GET' request without admin role to '/cluster/stats/<tenant-id>' will result
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in HTTP status code 403 (Permission denied).
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This option was discussed and rejected due to the fact that /cluster/stats
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collide with /cluster/<cluster-name/id>.
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Security impact
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---------------
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There will be changes to policy.json file that enable access to '/stats'
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endpoint to owner and admin (using a policy rule admin_or_owner).
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Notifications impact
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--------------------
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None
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Other end user impact
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---------------------
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New /stats endpoint will be available to users.
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Performance impact
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------------------
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None
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Other deployer impact
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---------------------
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None.
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Developer impact
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----------------
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None
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Implementation
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--------------
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Assignee(s)
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-----------
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Primary assignee
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vijendar-komalla
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Work Items
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----------
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1. Implement /stats API in Magnum service.
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2. Document new API.
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3. Update Magnum CLI to expose stats functionality.
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Dependencies
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------------
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None
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Testing
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-------
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1. Since a new stats endpoint will be introduced with this proposal, need to
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update some unit tests.
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2. Add unit tests and functional tests for new functionality introduced.
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Documentation Impact
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--------------------
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Update API documentation to include stats API information.
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References
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----------
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[1] - Magnum cluster statistics API blueprint:
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https://blueprints.launchpad.net/magnum/+spec/magnum-stats-api
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[2] - Proposed change under review:
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https://review.openstack.org/391301
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