Version skew testing

[tallclair]

As we make changes to Konnectivity, it is important that the newer components remain compatible with older components so that the system continues to function during upgrades and other version skew scenarios. However, we currently have no visibility into this. We should add tests that run against skewed versions.

Specifically, we need to test version skew across client/server, and agent/server. I propose we update the tests in the tests directory to run against skewed versions.

Implementation steps:

• 1. Refactor integration tests to prepare for proxy-server & agent skew testing #520
• 2. Implement External{ProxyServer,Agent}Runner, which takes an external binary to run for the server/agent, and accesses the measurements through prometheus metrics. Expose test flags to select a binary (or the in-tree version).
  • Run integration tests against an external agent process #552
• 3. Implement a version_skew_test script that handles fetching target tagged versions, compiling, and running the tests.
• 4. Set up CI jobs for skew testing
• 5. Refactor client operations to enable external client testing via the test-client binary.
• 6. Implement ExternalClient, update version_skew_test to run tests with the external client

/assign

[jkh52]

#553 (github actions using kind) could be an approach here for how to specify the versions under test. (Similar to that, but use real container image registry + version tags).

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/lifecycle stale

[tallclair]

/triage accepted
/remove-lifecycle stale