## Reference

### Design details

Broadly, `istio-cni` accomplishes ambient redirection by instructing ztunnel to set up sockets within the application pod network namespace, where:

- one end of the socket is in the application pod
- and the other end is in ztunnel's pod

and setting up iptables rules to funnel traffic thru that socket "tube" to ztunnel and back.

WD=$(dirname "$0")
WD=$(cd "$WD"; pwd)

set -eux

# This script sets up the plain text rendered deployments for addons
# See samples/addons/README.md for more information

ADDONS="${WD}/../../samples/addons"
DASHBOARDS="${WD}/dashboards"
mkdir -p "${ADDONS}"
TMP=$(mktemp -d)
LOKI_VERSION=${LOKI_VERSION:-"6.0.0"}
GRAFANA_VERSION=${GRAFANA_VERSION:-"7.3.7"}

# Set up kiali
{
helm3 template kiali-server \
  --namespace istio-system \

// continuously for some time. How often to update the EventSeries is up to the event reporters.
// The default event reporter in "k8s.io/client-go/tools/events/event_broadcaster.go" shows
// how this struct is updated on heartbeats and can guide customized reporter implementations.
message EventSeries {
  // count is the number of occurrences in this series up to the last heartbeat time.
  optional int32 count = 1;

	kubeconfig := conf.Kubernetes.Kubeconfig

	config, err := kube.DefaultRestConfig(kubeconfig, "")
	if err != nil {
		log.Errorf("Failed setting up kubernetes client with kubeconfig %s", kubeconfig)
		return nil, err
	}

	log.Debugf("istio-cni set up kubernetes client with kubeconfig %s", kubeconfig)

	// Create the client
	return kubernetes.NewForConfig(config)
}

// getK8sPodInfo returns information of a POD

	} else if c.cfg.LabelPods {
		return c.labelBrokenPod(pod)
	}
	return nil
}

// repairPod actually dynamically repairs a pod. This is done by entering the pods network namespace and setting up rules.
// This differs from the general CNI plugin flow, which triggers before the pod fully starts.
// Additionally, we need to jump through hoops to find the network namespace.

# We set up anonymous authentication as this is for demos.
auth:
  strategy: anonymous
deployment:
  pod_labels:
    sidecar.istio.io/inject: "false"
  accessible_namespaces:
  - '**'
  ingress_enabled: false
login_token:
  signing_key: CHANGEME00000000
external_services:
  # Kiali will not start up without tracing service. We don't want to require it.
  tracing:

  // Absolute number is calculated from percentage by rounding up.
  // Defaults to 25%.
  // Example: when this is set to 30%, the new ReplicaSet can be scaled up immediately when
  // the rolling update starts, such that the total number of old and new pods do not exceed
  // 130% of desired pods. Once old pods have been killed,
  // new ReplicaSet can be scaled up further, ensuring that total number of pods running

# determine if a retry should be attempted.
# Example: retry.sh "connection timed out" ./my-flaky-script.sh some args
# This will run "my-flaky-script.sh", retrying any failed runs that output "connection timed out" up
# to 5 times.

function fail {
  echo "${1}" >&2
  exit 1
}

function isatty() {
 if [ -t 1 ] ; then
   return 0
  else
   return 1
  fi
}

function retry {
  local tmpFile

{{/*Set up roles for Istio Gateway. Not required for gateway-api*/}}
{{- if .Values.rbac.enabled }}
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  name: {{ include "gateway.serviceAccountName" . }}
  namespace: {{ .Release.Namespace }}
  labels:
    {{- include "gateway.labels" . | nindent 4}}
  annotations:
    {{- .Values.annotations | toYaml | nindent 4 }}
rules:
- apiGroups: [""]
  resources: ["secrets"]

}

func forEachLoopbackRoute(cfg *Config, f func(*netlink.Route) error) error {
	loopbackLink, err := netlink.LinkByName("lo")
	if err != nil {
		return fmt.Errorf("failed to find 'lo' link: %v", err)
	}

	// Set up netlink routes for localhost
	cidrs := []string{"0.0.0.0/0"}
	if cfg.EnableIPv6 {
		cidrs = append(cidrs, "0::0/0")
	}
	for _, fullCIDR := range cidrs {
		_, localhostDst, err := net.ParseCIDR(fullCIDR)