⚠ leaderelection: use 'leases' as default resource lock object

[joelanford]

Update the default resource lock from configmapsleases to leases.

The previous default (since v0.7.0) was configmapsleases, which is the migration step from configmaps to leases. Since the default was configmapsleases for over a year, spanning five minor releases, any actively maintained operators are very likely to have a released version that uses configmapsleases. Therefore defaulting to leases now should be safe.

Any operators currently on a version <0.7.0 should migrate from configmaps to leases via configmapsleases.

• If an operator is currently on version <v0.7.0, it is hardcoded to using configmaps
• If an operator is currently in the range v0.7.0 to a version prior to this PR merging, it is configurable, but defaulted to configmapsleases.
• If an operator is using a version of controller-runtime containing this PR, it is configurable but defaulted to leases.

Operators currently using configmaps should:

1. Release a version (A) of their operator that uses controller-runtime v0.7.0+ (if jumping directly to a version of controller-runtime containing this PR, you should explicitly set configmapsleases when configuring leader election in this version)
2. Release a subsequent version (B) of their operator that uses a version of controller-runtime containing this PR (or if not bumping, you should explicitly set leases when configuring leader election in this version)
3. Ensure operators upgrade through A before getting to B.

See kubernetes/kubernetes#107454 (This PR moves controller-runtime from step x+1 to x+2)

Signed-off-by: Joe Lanford [email protected]

[joelanford]

/test pull-controller-runtime-test-master

[joelanford]

/test pull-controller-runtime-test-master

[vincepri]

/lgtm

[k8s-ci-robot]

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