Customizing the installation configuration
Before you begin, check the following prerequisites:
- Download the Istio release.
- Perform any necessary platform-specific setup.
- Check the Requirements for Pods and Services.
In addition to installing any of Istio’s built-in
istioctl install provides a complete API for customizing the configuration.
The configuration parameters in this API can be set individually using
--set options on the command
line. For example, to enable debug logging in a default configuration profile, use this command:
$ istioctl install --set values.global.logging.level=debug
IstioOperator configuration can be specified in a YAML file and passed to
istioctl using the
$ istioctl install -f samples/operator/pilot-k8s.yaml
Identify an Istio component
IstioOperator API defines components as shown in the table below:
The configurable settings for each of these components are available in the API under
For example, to use the API to change (to false) the
enabled setting for the
pilot component, use
--set components.pilot.enabled=false or set it in an
IstioOperator resource like this:
apiVersion: install.istio.io/v1alpha1 kind: IstioOperator spec: components: pilot: enabled: false
All of the components also share a common API for changing Kubernetes-specific settings, under
components.<component name>.k8s, as described in the following section.
Customize Kubernetes settings
IstioOperator API allows each component’s Kubernetes settings to be customized in a consistent way.
Each component has a
which allows the following settings to be changed. Use this list to identify the setting to customize:
- Readiness probes
- Replica count
- Pod annotations
- Service annotations
- Priority class name
- Node selector
- Affinity and anti-affinity
- Pod security context
All of these Kubernetes settings use the Kubernetes API definitions, so Kubernetes documentation can be used for reference.
The following example overlay file adjusts the resources and horizontal pod autoscaling settings for Pilot:
apiVersion: install.istio.io/v1alpha1 kind: IstioOperator spec: components: pilot: k8s: resources: requests: cpu: 1000m # override from default 500m memory: 4096Mi # ... default 2048Mi hpaSpec: maxReplicas: 10 # ... default 5 minReplicas: 2 # ... default 1
istioctl install to apply the modified settings to the cluster:
$ istioctl install -f samples/operator/pilot-k8s.yaml
Customize Istio settings using the Helm API
IstioOperator API includes a pass-through interface to the Helm API
The following YAML file configures global and Pilot settings through the Helm API:
apiVersion: install.istio.io/v1alpha1 kind: IstioOperator spec: values: pilot: traceSampling: 0.1 # override from 1.0 global: monitoringPort: 15014
Some parameters will temporarily exist in both the Helm and
IstioOperator APIs, including Kubernetes resources,
namespaces and enablement settings. The Istio community recommends using the
IstioOperator API as it is more
consistent, is validated, and follows the community graduation process.
Gateways are a special type of component, since multiple ingress and egress gateways can be defined. In the
IstioOperator API, gateways are defined as a list type.
default profile installs one ingress gateway, called
istio-ingressgateway. You can inspect the default values
for this gateway:
$ istioctl profile dump --config-path components.ingressGateways $ istioctl profile dump --config-path values.gateways.istio-ingressgateway
These commands show both the
IstioOperator and Helm settings for the gateway, which are used together to define the
generated gateway resources. The built-in gateways can be customized just like any other component.
A new user gateway can be created by adding a new list entry:
apiVersion: install.istio.io/v1alpha1 kind: IstioOperator spec: components: ingressGateways: - name: istio-ingressgateway enabled: true - namespace: user-ingressgateway-ns name: ilb-gateway enabled: true k8s: resources: requests: cpu: 200m serviceAnnotations: cloud.google.com/load-balancer-type: "internal" service: ports: - port: 8060 targetPort: 8060 name: tcp-citadel-grpc-tls - port: 5353 name: tcp-dns
Note that Helm values (
spec.values.gateways.istio-ingressgateway/egressgateway) are shared by all ingress/egress
gateways. If these must be customized per gateway, it is recommended to use a separate IstioOperator CR to generate
a manifest for the user gateways, separate from the main Istio installation:
apiVersion: install.istio.io/v1alpha1 kind: IstioOperator spec: profile: empty components: ingressGateways: - name: ilb-gateway namespace: user-ingressgateway-ns enabled: true # Copy settings from istio-ingressgateway as needed. values: gateways: istio-ingressgateway: debug: error
Advanced install customization
Customizing external charts and profiles
manifest generate and
profile commands can use any of the following sources for charts and
- compiled in charts. This is the default if no
--manifestsoption is set. The compiled in charts are the same as those in the
manifests/directory of the Istio release
- charts in the local file system, e.g.,
istioctl install --manifests istio-1.18.0/manifests.
Local file system charts and profiles can be customized by editing the files in
manifests/. For extensive changes,
we recommend making a copy of the
manifests directory and make changes there. Note, however, that the content layout
manifests directory must be preserved.
Profiles, found under
manifests/profiles/, can be edited and new ones added by creating new files with the
desired profile name and a
istioctl scans the
profiles subdirectory and all profiles found there
can be referenced by name in the
IstioOperatorSpec profile field. Built-in profiles are overlaid on the default profile YAML before user
overlays are applied. For example, you can create a new profile file called
custom1.yaml which customizes some settings
default profile, and then apply a user overlay file on top of that:
$ istioctl manifest generate --manifests mycharts/ --set profile=custom1 -f path-to-user-overlay.yaml
In this case, the
user-overlay.yaml files will be overlaid on the
default.yaml file to obtain the
final values used as the input for manifest generation.
In general, creating new profiles is not necessary since a similar result can be achieved by passing multiple overlay files. For example, the command above is equivalent to passing two user overlay files:
$ istioctl manifest generate --manifests mycharts/ -f manifests/profiles/custom1.yaml -f path-to-user-overlay.yaml
Creating a custom profile is only required if you need to refer to the profile by name through the
Patching the output manifest
IstioOperator CR, input to
istioctl, is used to generate the output manifest containing the
Kubernetes resources to be applied to the cluster. The output manifest can be further customized to add, modify or delete resources
IstioOperator overlays API, after it is
generated but before it is applied to the cluster.
The following example overlay file (
patch.yaml) demonstrates the type of output manifest patching that can be done:
apiVersion: install.istio.io/v1alpha1 kind: IstioOperator spec: profile: empty hub: docker.io/istio tag: 1.1.6 components: pilot: enabled: true namespace: istio-control k8s: overlays: - kind: Deployment name: istiod patches: # Select list item by value - path: spec.template.spec.containers.[name:discovery].args.[30m] value: "60m" # overridden from 30m # Select list item by key:value - path: spec.template.spec.containers.[name:discovery].ports.[containerPort:8080].containerPort value: 1234 # Override with object (note | on value: first line) - path: spec.template.spec.containers.[name:discovery].env.[name:POD_NAMESPACE].valueFrom value: | fieldRef: apiVersion: v2 fieldPath: metadata.myPath # Deletion of list item - path: spec.template.spec.containers.[name:discovery].env.[name:REVISION] # Deletion of map item - path: spec.template.spec.containers.[name:discovery].securityContext - kind: Service name: istiod patches: - path: spec.ports.[name:https-dns].port value: 11111 # OVERRIDDEN
Passing the file to
istioctl manifest generate -f patch.yaml applies the above patches to the default profile output
manifest. The two patched resources will be modified as shown below (some parts of the resources are omitted for
apiVersion: apps/v1 kind: Deployment metadata: name: istiod spec: template: spec: containers: - args: - 60m env: - name: POD_NAMESPACE valueFrom: fieldRef: apiVersion: v2 fieldPath: metadata.myPath name: discovery ports: - containerPort: 1234 --- apiVersion: v1 kind: Service metadata: name: istiod spec: ports: - name: https-dns port: 11111 ---
Note that the patches are applied in the given order. Each patch is applied over the output from the previous patch. Paths in patches that don’t exist in the output manifest will be created.
List item path selection
istioctl --set flag and the
k8s.overlays field in
IstioOperator CR support list item selection by
[value] or by
The –set flag also creates any intermediate nodes in the path that are missing in the resource.