Swift Global Cluster¶
Add support for Swift Global Cluster feature to Swift charms.
Problem Description¶
At the moment Swift charms do not support the Swift Global Cluster feature which is already available in the upstream:
https://docs.openstack.org/swift/latest/overview_global_cluster.html
As a result it is not possible to deploy Swift clusters in a multi-region mode using Swift charms.
Proposed Change¶
The proposed change can be split to the following items:
Add new config options to swift-storage charm to handle the following parameters:
“region”:
purpose: specifies region to request membership data type: int valid values: natural number
“account-server-port-rep”:
purpose: specifies listening port of the swift-account-replicator service data type: int valid values: 0 - 65535
“container-server-port-rep”:
purpose: specifies listening port of the swift-container-replicator service data type: int valid values: 0 - 65535
“object-server-port-rep”:
purpose: specifies listening port of the swift-object-replicator service data type: int valid values: 0 - 65535
Add new config options to swift-proxy charm to handle the following parameters:
“enable-multi-region”:
purpose: specifies whether the Swift Global Cluster feature should be used data type: boolean valid values: True / False
“read-affinity”:
purpose: specifies which backend servers to prefer on reads data type: string valid values: matches “^rd+z?(d+)?=d+(,s?rd+z?(d+)?=d+)*$” pattern
“write-affinity”:
purpose: specifies which backend servers to prefer on writes data type: string valid values: matches “^rd+(,s?rd+)*$” pattern
“write-affinity-node-count”:
purpose: specifies how many local objects will be tried before falling back to non-local ones data type: string valid values: matches “^d+(s*sreplicas)?$” pattern
Update template files to contain options required by the Swift Global Cluster feature.
Rename and change location of template configuration files responsible for Swift account, container and object services to match the schema required by the Swift Global Cluster feature.
Extend relation data exchanged between swift-storage and swift-proxy nodes with the region and other replication information.
Implement ‘rings-distributor’ - ‘rings-consumer’ relation based on a common interface (‘swift-global-cluster’) in swift-proxy charm to handle rings distribution across all proxy nodes participating in the multi-region deployment.
Update test files.
Update the documentation with information on how to setup Swift in multi-region mode.
Alternatives¶
At the moment there is no alternative to the Swift Global Cluster feature.
Implementation¶
Assignee(s)¶
- Primary assignee:
tkurek
Gerrit Topic¶
Use Gerrit topic “swift-global-cluster” for all patches related to this spec.
git-review -t bug/1815879
Work Items¶
Update swift-proxy charm¶
Update ‘config.yaml’ file to add new options
Update template files with new options
Update ‘metadata.yaml’ file to add the new relation
Add hook files as symlinks to the ‘swift_hooks.py’ file
Update ‘swift_hooks.py’ file with hook definitions for the new relation
Update test files
Update ‘README.md’ file to describe the feature
Update other files (if needed) to implement the feature
Update swift-storage charm¶
Update ‘config.yaml’ file to add new options
Rename and change location of template configuration files responsible for Swift account, container and object services to match the schema required by the feature.
Update ‘metadata.yaml’ file to add extra bindings (‘cluster’ and ‘replication’)
Update ‘swift_storage_relation_joined’ hook definition with extended relation data
Update test files
Update ‘README.md’ file to describe the feature
Update other files (if needed) to implement the feature
Repositories¶
No new git repositories will be required to implement this feature.
Documentation¶
The README files of swift-proxy and swift-storage charms should be updated with instructions on how to setup Swift in multi-region mode.
Security¶
No security implications for this change.
Testing¶
Unit and functional tests of swift-proxy and swift-storage charms will need to be updated to support implementation of this feature.
Dependencies¶
No external dependencies.
