Shulou(Shulou.com)06/01 Report--

In this issue, the editor will bring you about how to understand Istio Operator. The article is rich in content and analyzes and narrates it from a professional point of view. I hope you can get something after reading this article.

Kubernetes operator provides a mode to encode human operation and maintenance knowledge into software, and it is a popular method to simplify the management of software infrastructure components. Istio is an ideal choice for automatic operator because its management is challenging.

So far, Helm has been the primary tool for installing and upgrading Istio. Istio 1.4 introduces a new installation method using istioctl. This new installation method builds on the advantages of Helm and adds the following:

Users only need to install one tool: istioctl

Validate all API fields

Mini customizations that are not in API do not need to change chart or API

Version-specific upgrade hook can be easily and robustly implemented

The Helm installation method is being deprecated. Upgrading from Istio 1.4 to a version with no Helm installed by default will also be replaced by a new istioctl upgrade feature.

The new istioctl installation command uses a custom resource to configure the installation. Custom resources are part of a new Istio operator implementation designed to simplify common administrative tasks such as installation, upgrades, and complex Istio configuration changes. Verification and inspection of installations and upgrades are tightly integrated with tools to prevent common errors and simplify troubleshooting.

Operator API

Each operator implementation needs a custom resource definition (CRD) to define its custom resource, its API. Istio's operator API is defined by IstioControlPlane CRD, which is generated by an IstioControlPlane prototype. API supports all current Istio profiles by using a field to select profile. For example, the following IstioControlPlane resource uses demo profile to configure Istio:

ApiVersion: install.istio.io/v1alpha2kind: IstioControlPlanemetadata: namespace: istio-operator name: example-istiocontrolplanespec: profile: demo

You can then use other settings to customize the configuration. For example, disable telemetry:

ApiVersion: install.istio.io/v1alpha2kind: IstioControlPlanemetadata: namespace: istio-operator name: example-istiocontrolplanespec: profile: demo telemetry:enabled: false is installed through istioctl

The recommended way to use Istio operator API is through a new set of istioctl commands. For example, to install Istio in a cluster:

$istioctl manifest apply-f

Change the installation configuration by editing the configuration file and executing istioctl manifest apply again.

Upgrade to the new version of Istio:

$istioctl x upgrade-f

In addition to specifying the complete configuration in the IstioControlPlane resource, the istioctl command can also pass individual settings using the-- set flag:

$istioctl manifest apply-set telemetry.enabled=false

There are many other istioctl commands, for example, that can help you list, display, and compare configurations profile and manifest.

Please refer to the Istio installation instructions for more information.

Istio Controller (alpha)

Operator implementations use Kubernetes controller to continuously monitor their custom resources and apply corresponding configuration changes. Istio controller monitors an IstioControlPlane resource and responds to changes by updating the Istio installation configuration in the corresponding cluster.

In version 1.4, Istio controller is in the alpha stage of development and is not fully integrated into istioctl. However, you can use the kubectl command to do experiments. For example, to install controller and the default version of Istio into the cluster, run the following command:

$kubectl apply-f https:///operator.yaml $kubectl apply-f https:///default-cr.yaml

Then you can modify the installation configuration of Istio:

$kubectl edit istiocontrolplane example-istiocontrolplane-n istio-system

Once the resource is updated, controller will detect these changes and update the Istio installation accordingly.

The Operator controller and istioctl commands share the same implementation. The important difference lies in its execution context. For istioctl, the operation runs in the command execution and security context of the administrative user. For controller, a pod in the cluster runs code in its security context. In both cases, the configuration is validated against a schema and the same correctness check is performed.

Migrate from Helm

To facilitate the transition from using Helm, istioctl and controller support transparent access to the Helm installation API.

You can use istioctl-- set to pass Helm configuration options by passing the string values. Exe. Put it in front of the configuration options. For example, for this Helm command:

$helm template...-- set global.mtls.enabled=true

You can use the command istioctl:

$istioctl manifest generate...-- set values.global.mtls.enabled=true

You can also set Helm configuration values in an IstioControlPlane custom resource. See customize Istio settings using Helm.

Another feature that can help with migration from Helm is the alpha command: istioctl manifest migrate. This command can be used to automatically convert Helm values.yaml files to the appropriate IstioControlPlane configuration.

Realize

Several frameworks have been created to help implement operator by generating stubs for some or all components. Istio operator was created with the help of kubebuilder and operator framework. The installation of Istio now uses proto to describe API so that the execution runtime can be validated through schema.

More information about the implementation can be found in the README and ARCHITECTURE documents in the Istio operator repository.

Starting with Istio 1.4, the Helm installation will be replaced by the new istioctl command, which uses the new operator custom resource definition, IstioControlPlane, as the configuration API. An alpha controller is also provided for early experiments with operator.

Both the new istioctl command and operator controller verify the configuration schema and perform a series of checks for installation changes or upgrades. These checks are tightly integrated with tools to prevent common errors and simplify troubleshooting.

Istio maintainers expect this new approach to improve the user experience during installation and upgrade, better stabilize the installation of API, and help users better manage and monitor their Istio installations.

The above is the editor for you to share how to understand Istio Operator, if you happen to have similar doubts, you might as well refer to the above analysis to understand. If you want to know more about it, you are welcome to follow the industry information channel.

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