# Istio Agent

This document describes the internal architecture of Istio agent.

## High Level overview

![High Level overview](docs/overview.svg)

At a high level, the Istio agent acts as an intermediate proxy between Istiod and Envoy. This is done
at two levels. For distributing workload certificates, Envoy will send [SDS](https://www.envoyproxy.io/docs/envoy/latest/configuration/security/secret)

    // US region agents have name "EC2-XXX"
    doesNotContain("teamcity.agent.name", "EC2")
}

/**
 * We have some "shared" host where a Linux build agent and a Windows build agent
 * both run on the same bare metal. Some builds require exclusive access to the
 * hardware resources (e.g. performance test).
 */
fun Requirements.requiresNotSharedHost() {
    doesNotContain("agent.host.type", "shared")
}

-Dorg.gradle.daemon.idletimeout=120000 -Dorg.gradle.daemon.registry.base=C:\\some\\agent\\workspace\\build\\daemon -Dorg.gradle.native.dir=C:\\some\\agent\\workspace\\intTestHomeDir\\worker-1\\native -Dorg.gradle.deprecation.trace=true -Djava.io.tmpdir=C:\\some\\agent\\workspace\\subprojects\\osgi\\build\\tmp -Dfile.encoding=windows-1252 -Dorg.gradle.classloaderscope.strict=true -ea -ea "-Dorg.gradle.appname=gradle" -classpath "C:\\some\\agent\\workspace\\subprojects\\osgi\\build\\integ test\\bin\\..\\lib\\gra...

// SecretItemDiff represents a secret that has been diffed between nodeagent and proxy
type SecretItemDiff struct {
	Agent string `json:"agent"`
	Proxy string `json:"proxy"`
	SecretItem
}

// SecretItem is an intermediate representation of secrets, used to provide a common
// format between the envoy proxy secrets and node agent output which can be diffed
type SecretItem struct {
	Name        string `json:"resource_name"`

RELEASE_LDFLAGS='-extldflags -static -s -w'
endif

# List of all binaries to build
# We split the binaries into "agent" binaries and standard ones. This corresponds to build "agent".
# This allows conditional compilation to avoid pulling in costly dependencies to the agent, such as XDS and k8s.
AGENT_BINARIES:=./pilot/cmd/pilot-agent
STANDARD_BINARIES:=./istioctl/cmd/istioctl \
  ./pilot/cmd/pilot-discovery \
  ./pkg/test/echo/cmd/client \

	MonitoringPort           = "monitoring-port"
	LogUDSSocket             = "log-uds-socket"
	ZtunnelUDSAddress        = "ztunnel-uds-address"
	CNIEventSocket           = "cni-event-address"
	CNIAgentRunDir           = "cni-agent-run-dir"
	ExcludeNamespaces        = "exclude-namespaces"
	AmbientEnabled           = "ambient-enabled"
	AmbientDNSCapture        = "ambient-dns-capture"
	AmbientIPv6              = "ambient-ipv6"

		if cfg.InstallConfig.AmbientEnabled {
			// Start ambient controller

			// node agent will spawn a goroutine and watch the K8S API for events,
			// as well as listen for messages from the CNI binary.
			cniEventAddr := filepath.Join(cfg.InstallConfig.CNIAgentRunDir, constants.CNIEventSocketName)
			log.Infof("Starting ambient node agent with inpod redirect mode on socket %s", cniEventAddr)

					"name":"TestDistribution"
				},
				"subprojects":[
					"workers",
					"wrapper-main",
					"testing-base-infrastructure",
					"messaging",
					"war",
					"instrumentation-agent-services",
					"build-profile",
					"resources-gcs",
					"ear",
					"plugins-distribution",
					"problems"
				]
			},
			{
				"parallelizationMethod":{
					"name":"TestDistribution"

            }
            script {
                name = "CLEAN_M2"
                executionMode = BuildStep.ExecutionMode.ALWAYS
                scriptContent = checkCleanDirUnixLike("%teamcity.agent.jvm.user.home%/.m2/.develocity", exitOnFailure = false)
            }
        }
    }

				if err != nil {
					fmt.Fprintf(os.Stderr, "Skip the agent in Pod %s due to the error: %s\n", namespacedName, err.Error())
					continue
				}
				responses = append(responses, resp)
			}
			token = list.ListMeta.GetContinue()
			if token == "" {
				break
			}
		}
	} else {
		// If there is a specific pod name in ResourceName, use the agent in the pod.
		if len(dr.ResourceNames) != 1 {