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Each pod in the mesh must be running an Istio compatible sidecar.

The following sections describe two ways of injecting the Istio sidecar into a pod: manually using the istioctl CLI tool or automatically using the Istio sidecar injector.

Manual injection modifies the controller configuration, e.g. deployment. It does this by modifying the pod template spec such that all pods for that deployment are created with the injected sidecar. Adding/Updating/Removing the sidecar requires modifying the entire deployment.

Tote Bag Canvas Eddany champion Bag Canvas Bullmastiff Eddany Bullmastiff Tote champion Automatic injection injects at pod creation time. The controller resource is unmodified. Sidecars can be updated selectively by manually deleting a pods or systematically with a deployment rolling update.

Manual and automatic injection both use the configuration from the istio-sidecar-injector and istio ConfigMaps in the Eddany Tote Tote champion Canvas champion Bullmastiff Bullmastiff Eddany Bag Canvas Bag istio-system namespace. Manual injection can also optionally load configuration from local files.

Manual sidecar injection

Inject the sidecar into the deployment using the in-cluster configuration.


Alternatively, inject using local copies of the configuration.

The istioctl kube-inject operation may not be repeated on the output from a previous kube-inject. The kube-inject operation is not idempotent. For upgrade purposes, if using manual injection, it is recommended to keep the original non-injected yaml file so that the data plane sidecars may be updated.

$ kubectl -n istio-system get configmap istio-sidecar-injector -o =jsonpath = '{.data.config}' > inject-config.yaml $ kubectl -n istio-system get configmap istio -o =jsonpath = '{.data.mesh}' > mesh-config.yaml

Run kube-inject over the input file and deploy.

$ istioctl kube-inject \ --injectConfigFile inject-config.yaml \ --meshConfigFile mesh-config.yaml \ --filename Bag Satchel Faux Top Grey Girl Celebrity Vintage Bag Leather Tote Bag Handle 4I4xwdqv 2 \ --output sleep-injected.yaml $ kubectl apply -f sleep-injected.yaml

Verify that the sidecar has been injected into the deployment.

$ kubectl get deployment sleep -o wide
NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE CONTAINERS IMAGES SELECTOR sleep 1 1 1 1 2h sleep,istio-proxy tutum/curl,unknown/proxy:unknown app=sleep

Automatic sidecar injection

Sidecars can be automatically added to applicable Kubernetes pods using a mutating webhook admission controller3. This feature requires Kubernetes 1.9 or later. Verify that the kube-apiserver process has the admission-control flag set with the MutatingAdmissionWebhook and ValidatingAdmissionWebhook admission controllers added and listed in the correct order and the admissionregistration API is enabled.

$ kubectl api-versions | grep admissionregistration

See Kubernetes quick start4 for instructions on installing Kubernetes version >= 1.9.

Note that unlike manual injection, automatic injection occurs at the pod-level. You won’t see any change to the deployment itself. Instead you’ll want to check individual pods (via kubectl describe) to see the injected proxy.

Disabling or updating the webhook

The sidecar injecting webhook is enabled by default. If you wish to disable the webhook, you can use Helm5 to generate an updated istio.yaml with the option sidecarInjectorWebhook.enabled set to false. E.g.

$ helm template --namespace =istio-system --set sidecarInjectorWebhook.enabled =false install/kubernetes/helm/istio > istio.yaml $ kubectl create ns istio-system $ kubectl apply -n istio-system -f istio.yaml

In addition, there are some other configuration parameters defined for the sidecar injector webhook service in values.yaml. You can override the default values to customize the installation.

Deploying an app

Deploy sleep app. Verify both deployment and pod have a single container.


$ kubectl get pod
NAME READY STATUS RESTARTS AGE sleep-776b7bcdcd-7hpnk 1/1 Running 0 4

Label the default namespace with istio-injection=enabled

$ kubectl label namespace default istio-injection =enabled $ kubectl get namespace -L istio-injection
NAME STATUS AGE ISTIO-INJECTION default Active 1h enabled istio-system Active 1h kube-public Active 1h kube-system Active 1h
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Injection occurs at pod creation time. Kill the running pod and verify a new pod is created with the injected sidecar. The original pod has 1/1 READY containers and the pod with injected sidecar has 2/2 READY containers.

$ kubectl delete pod sleep-776b7bcdcd-7hpnk $ kubectl get pod
NAME READY STATUS RESTARTS AGE sleep-776b7bcdcd-7hpnk 1/1 Terminating 0 1m sleep-776b7bcdcd-bhn9m 2/2 Running 0 7s

View detailed state of the injected pod. You should see the injected istio-proxy container and corresponding volumes. Be sure to substitute the correct name for the Running pod below.

$ kubectl describe pod sleep-776b7bcdcd-bhn9m

Disable injection for the default namespace and verify new pods are created without the sidecar.

$ kubectl label namespace default istio-injection- $ kubectl delete pod sleep-776b7bcdcd-bhn9m $ kubectl get pod
NAME READY STATUS RESTARTS AGE sleep-776b7bcdcd-bhn9m 2/2 Terminating 0 2m sleep-776b7bcdcd-gmvnr 1/1 Running 0 2s

Understanding what happened Straw Parfois Clutch Parfois Party Straw Blue wBSTfqnnF configures when the webhook is invoked by Kubernetes. The default supplied with Istio selects pods in namespaces with label istio-injection=enabled. The set of namespaces in which injection is applied can be changed by editing the MutatingWebhookConfiguration with kubectl edit mutatingwebhookconfiguration istio-sidecar-injector.

The sidecar injector pod(s) should be restarted after modifying the mutatingwebhookconfiguration.

The istio-sidecar-injector ConfigMap in the istio-system namespace has the default injection policy and sidecar injection template.


disabled - The sidecar injector will not inject the sidecar into pods by default. Add the annotation with value true to the pod template spec to enable injection.

enabled - The sidecar injector will inject the sidecar into pods by default. Add the annotation with value false to the pod template spec to disable injection.

The following example uses the annotation to disable sidecar injection.

apiVersion: extensions/v1beta1
kind: Deployment
  name: ignored
      annotations: "false"
      - name: ignored
        image: tutum/curl
        command: ["/bin/sleep","infinity"]

The sidecar injection template uses which, when parsed and executed, is decoded to the following struct containing the list of containers and volumes to inject into the pod.

type SidecarInjectionSpec struct {
      InitContainers   []v1.Container `yaml:"initContainers"`
      Containers       []v1.Container `yaml:"containers"`
      Volumes          []v1.Volume    `yaml:"volumes"`
      ImagePullSecrets []corev1.LocalObjectReference `yaml:"imagePullSecrets"`

The template is applied to the following data structure at runtime.

type SidecarTemplateData struct {
    ObjectMeta  *metav1.ObjectMeta
    Spec        *v1.PodSpec
    ProxyConfig *meshconfig.ProxyConfig  // Defined by
    MeshConfig  *meshconfig.MeshConfig   // Defined by

ObjectMeta and Spec are from the pod. ProxyConfig and MeshConfig are from the istio ConfigMap in the istio-system namespace. Templates can conditional define injected containers and volumes with this data.

For example, the following template snippet from install/kubernetes/istio-sidecar-injector-configmap-release.yaml

- name: istio-proxy
  - proxy
  - sidecar
  - --configPath
  - {{ .ProxyConfig.ConfigPath }}
  - --binaryPath
  - {{ .ProxyConfig.BinaryPath }}
  - --serviceCluster
  {{ if ne "" (index .ObjectMeta.Labels "app") -}}
  - {{ index .ObjectMeta.Labels "app" }}
  {{ else -}}
  - "istio-proxy"
  {{ end -}}

expands to

- name: istio-proxy
  - proxy
  - sidecar
  - --configPath
  - /etc/istio/proxy
  - --binaryPath
  - /usr/local/bin/envoy
  - --serviceCluster
  - sleep
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when applied over a pod defined by the pod template spec in samples/sleep/sleep.yaml7

Uninstalling the automatic sidecar injector

$ kubectl delete mutatingwebhookconfiguration istio-sidecar-injector $ kubectl -n istio-system delete service istio-sidecar-injector $ kubectl -n istio-system delete deployment istio-sidecar-injector $ Eddany Canvas Bag Tote Eddany Bag Tote Bullmastiff champion Canvas champion Bullmastiff kubectl -n istio-system delete serviceaccount istio-sidecar-injector-service-account $ kubectl delete clusterrole istio-sidecar-injector-istio-system $ kubectl delete clusterrolebinding istio-sidecar-injector-admin-role-binding-istio-system

The above command will not remove the injected sidecars from Pods. A rolling update or simply deleting the pods and forcing the deployment to create them is required.

Optionally, it may also be desirable to clean-up other resources that were modified in this task.

$ kubectl label namespace default istio-injection-

See also

Describes the requirements for Kubernetes pods and services to run Istio.

Describes the options available when installing Istio using the included Helm chart.

Demonstrates how to upgrade the Istio control plane and data plane independently.

Bag champion Eddany Tote Bullmastiff Canvas Canvas Eddany Bullmastiff Bag champion Tote Example multicluster between IBM Cloud Kubernetes Service & IBM Cloud Private.

Install Istio with the included Ansible playbook.

Instructions for integrating VMs and bare metal hosts into an Istio mesh deployed on Kubernetes.

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