Historically, Istio had to really be consumed all-or-nothing for things to work as expected.
In particular, an easy answer to "I just want to have mTLS everywhere, then I can think about adopting the rest of service mesh" was desired.

## Goals

Ztunnel should:
* **Not break users**. This means that deploying Ztunnel should retain all existing Kubernetes behavior.

### Relationship between the CLI and controller

The CLI and controller share the same API and codebase for generating manifests from the API. You can think of the
controller as the CLI command `istioctl install` running in a loop in a pod in the cluster and using the config
from the in-cluster IstioOperator custom resource (CR).
There are two major differences:

			},
			expectPodUID:      "",
			expectContainerID: "45490e76e0878aaa4d9808f7d2eefba37f093c3efbba9838b6d8ab804d9bd814",
		},
		{
			name: "more than one container ID in cgroups",
			cgroupPaths: []string{
				"/user.slice",
				"/kubepods/pod2c48913c-b29f-11e7-9350-020968147796/9bca8d63d5fa610783847915bcff0ecac1273e5b4bed3f6fa1b07350e0135961",

be used to select a different 'environment'.

## Installing

The new installer is intended to be modular and very explicit about what is installed. It has
far more steps than the Istio installer - but each step is smaller and focused on a specific
feature, and can be performed by different people/teams at different times.

  // globalDefault specifies whether this PriorityClass should be considered as
  // the default priority for pods that do not have any priority class.
  // Only one PriorityClass can be marked as `globalDefault`. However, if more than
  // one PriorityClasses exists with their `globalDefault` field set to true,
  // the smallest value of such global default PriorityClasses will be used as the default priority.
  // +optional
  optional bool globalDefault = 3;

  // according to the corresponding EndpointSlice addressType field. Consumers
  // must handle different types of addresses in the context of their own
  // capabilities. This must contain at least one address but no more than
  // 100. These are all assumed to be fungible and clients may choose to only
  // use the first element. Refer to: https://issue.k8s.io/106267
  // +listType=set
  repeated string addresses = 1;

      {{- end }}
{{- end }}

{{/* We take the mesh config above, defined with individual values.yaml, and merge with .Values.meshConfig */}}
{{/* The intent here is that meshConfig.foo becomes the API, rather than re-inventing the API in values.yaml */}}
{{- $originalMesh := include "mesh" . | fromYaml }}
{{- $mesh := mergeOverwrite $originalMesh .Values.meshConfig }}

{{- if .Values.pilot.configMap }}
apiVersion: v1
kind: ConfigMap

  //
  // BorrowingCL(i) = round( NominalCL(i) * borrowingLimitPercent(i)/100.0 )
  //
  // The value of this field can be more than 100, implying that this
  // priority level can borrow a number of seats that is greater than
  // its own nominal concurrency limit (NominalCL).
  // When this field is left `nil`, the limit is effectively infinite.
  // +optional

  //
  // BorrowingCL(i) = round( NominalCL(i) * borrowingLimitPercent(i)/100.0 )
  //
  // The value of this field can be more than 100, implying that this
  // priority level can borrow a number of seats that is greater than
  // its own nominal concurrency limit (NominalCL).
  // When this field is left `nil`, the limit is effectively infinite.
  // +optional

  // Specifies the maximum desired number of pods the job should
  // run at any given time. The actual number of pods running in steady state will
  // be less than this number when ((.spec.completions - .status.successful) < .spec.parallelism),
  // i.e. when the work left to do is less than max parallelism.
  // More info: https://kubernetes.io/docs/concepts/workloads/controllers/jobs-run-to-completion/
  // +optional
  optional int32 parallelism = 1;