- For in-depth information about how to use Istio, visit [istio.io](https://istio.io)
- To ask questions and get assistance from our community, visit [GitHub Discussions](https://github.com/istio/istio/discussions)

## Architecture Standards

**Experimental!**

We'd like to capture our architectural decisions about the build tool as [Architectural Decision Records (ADRs)](https://adr.github.io/).
For now we just have this global repository of ADRs.
If we see fit, we can break these out to per-platform ones, or keep a hybrid approach to having global and platform-specific ADSs.

Our aim is to keep the process lightweight and approachable.

	//
	// Note that SortedList is used here because the istio sets class has no order guarantees,
	// and our unit tests will flake if rules have a nondeterministic ordering.
	// CLI: -t mangle -A ISTIO_PRERT -s 169.254.7.127 -p tcp -m tcp --dport <PROBEPORT> -j ACCEPT
	//
	// DESC: If this is one of our node-probe ports and is from our SNAT-ed/"special" hostside IP, short-circuit out here

release has many critical bug fixes and is safe to run in production. We're eager to stabilize our
new APIs so we can get out of alpha.

 *  New: Support Java 21's virtual threads (‘OpenJDK Project Loom’). We changed OkHttp's internals
    to use `Lock` and `Condition` instead of `synchronized` for best resource utilization.

    // Exists to test that our framework doesn't run it:
    @SuppressWarnings("unused")
    @ExampleDerivedFeature.Require({
      ExampleDerivedFeature.DERIVED_FEATURE_1,
      ExampleDerivedFeature.DERIVED_FEATURE_2
    })
    public void testRequiringTwoExplicitDerivedFeatures() throws Exception {
      doNotActuallyRunThis();
    }

    // Exists to test that our framework doesn't run it:

    // Exists to test that our framework doesn't run it:
    @SuppressWarnings("unused")
    @ExampleDerivedFeature.Require({
      ExampleDerivedFeature.DERIVED_FEATURE_1,
      ExampleDerivedFeature.DERIVED_FEATURE_2
    })
    public void testRequiringTwoExplicitDerivedFeatures() throws Exception {
      doNotActuallyRunThis();
    }

    // Exists to test that our framework doesn't run it:

flavor.

-   Snapshot API Docs: [guava][guava-snapshot-api-docs]
-   Snapshot API Diffs: [guava][guava-snapshot-api-diffs]

## Learn about Guava

-   Our users' guide, [Guava Explained]
-   [A nice collection](https://www.tfnico.com/presentations/google-guava) of
    other helpful links

## Links

-   [GitHub project](https://github.com/google/guava)

	switch event.Event {
	case controllers.EventAdd:
		// pod was added to our cache
		// we get here in 2 cases:
		// 1. new pod was created on our node
		// 2. we were restarted and current existing pods are added to our cache

		// We have no good way to distinguish between these two cases from here. But we don't need to!

			return false
		}
	}

	// For each candidate pod, iterate across all init containers searching for
	// crashlooping init containers that match our criteria
	for _, container := range pod.Status.InitContainerStatuses {
		// Skip the container if the InitContainerName is not a match and our
		// InitContainerName filter is non-empty.
		if c.cfg.InitContainerName != "" && container.Name != c.cfg.InitContainerName {
			continue
		}

## Configuration protocol

Ztunnel, of course, needs to be dynamically configured in order to make decisions on how it should handle traffic.
For this purpose, we chose to use xDS transport protocol due to our expertise and existing infrastructure, and because the protocol is well suited to our needs.