Files
virtual-kubelet/vendor/github.com/vmware/vic/lib/migration/plugins/plugins.md
Loc Nguyen 513cebe7b7 VMware vSphere Integrated Containers provider (#206)
* Add Virtual Kubelet provider for VIC

Initial virtual kubelet provider for VMware VIC.  This provider currently
handles creating and starting of a pod VM via the VIC portlayer and persona
server.  Image store handling via the VIC persona server.  This provider
currently requires the feature/wolfpack branch of VIC.

* Added pod stop and delete.  Also added node capacity.

Added the ability to stop and delete pod VMs via VIC.  Also retrieve
node capacity information from the VCH.

* Cleanup and readme file

Some file clean up and added a Readme.md markdown file for the VIC
provider.

* Cleaned up errors, added function comments, moved operation code

1. Cleaned up error handling.  Set standard for creating errors.
2. Added method prototype comments for all interface functions.
3. Moved PodCreator, PodStarter, PodStopper, and PodDeleter to a new folder.

* Add mocking code and unit tests for podcache, podcreator, and podstarter

Used the unit test framework used in VIC to handle assertions in the provider's
unit test.  Mocking code generated using OSS project mockery, which is compatible
with the testify assertion framework.

* Vendored packages for the VIC provider

Requires feature/wolfpack branch of VIC and a few specific commit sha of
projects used within VIC.

* Implementation of POD Stopper and Deleter unit tests (#4)

* Updated files for initial PR
2018-06-04 15:41:32 -07:00

4.1 KiB

Developer guideline to write a data migration plugin

Who and When to develop a data migration plugin

As upgrade design mentioned, every developer who changed configuration from VCH appliance configuration, container vm configuration, or key/value store, whatever it is, they should add data migration plugin here.

How to develop a data migration plugin

VM guestinfo changes including VCH appliance and container VM

  • Check if there is a file conflict with someone else's commit. If there is a conflict, that means there's another plugin being developed at the time - ensure that you do not use same plugin version number.
  • Create a new package in the lib/migration/plugins directory for your new plugin, say pluginX.
  • Add a new constant for the plugin version in lib/migration/feature/feature.go.
  • Add plugin files to the new package.
  • Your plugin might rely on previous version and current version, if you need the whole VCH appliance or container configuration definition, copy them to package lib/migration/config, with correct new package created. For example, if you are working on migration from version 4 to version 5, create a package named v4 if there is no one existing, and copy all old configuration files to there, and create a new package v5, copy all new configuration files to v5 package. Remember to update package name.
  • If only a few attributes are touched, you could define that piece of attribute definition in your plugin package, without whole configuration files copied in the above step. Which can save binary size, and also configuration encodeing/decoding time.
  • Develop plugin based on your specific change, read the input data, decoding to acceptable format, and change value inside of them. stop_singal_rename_sample.go is one VCH appliance configuration change sample, you can follow that to write your own plugin.
  • Register your plugin to data migration framework, and put the function in package pluginX's init() method.
    • Register appliance data migration plugin to manager.ApplianceConfigure category
    • Register container data migration plugin to manager.ContainerConfigure category
    • The two plugin targets are for different data, ensure that the type is selected correctly in registration.
  • Important: add import of your pluginX package in init.go of the plugin package to ensure that pluginX is registered dynamically.

key/value store changes

  • Check if there is a file conflict with someone else's commit. If there is a conflict, that means there's another plugin being developed at the time - ensure that you do not use same plugin version number.
  • Create a new package in the lib/migration/plugins directory for your new plugin, say pluginX.
  • Add a new constant for the plugin version in lib/migration/feature/feature.go.
  • Add your plugin files to the new package.
  • Develop plugin based on your specific change.
    • Create new key/value store file in datastore, instead of change in existing file. The new file for new version, e.g. v4, could use file name as XXX.v4, to differentiate with old version's file.
    • Copy all existing key/values to the new file, and update to the new file directly.
    • Write to new datastore file only, because old file is still correct if migration failed eventually.
  • Register your plugin to data migration framework, and put the function in package pluginX's init() method.
    • Register key/value store data migration plugin to manager.ApplianceConfigure category.
  • Important: add import of your pluginX package in init.go of the plugin package to ensure that pluginX is registered dynamically.

Note:

  • Plugin version should be greater than 0
  • If you changed both key/value store and VCH appliance configuration, please add two separate plugins for them. Eventually, data migration framework will execute both of them, but separation will make the code easy to read.
  • While copy configuration files, remove unnecessary methods from that file, to reduce binary file size

Add integration test

Be sure to add test scenario into upgrade test group, to cover your changes, to make sure after upgrade, your function works well