Planning to run Istio locally?¶

Changes to enable Istio locally¶

Update the ./deployment/helm/values-local.yaml file

a) New Variables:
- localDev: This variable will tell Helm when we are on our machine vs going through the pipeline.
- localRoute: This variable will supply a source and destination route for Istio mapping. In the example code below, you’ll see /myapp/, replace myapp with whatever you would like.
b) Existing Variables:
- green.enabled: & blue.enabled: Setting these to true will enable Blue/Green deployments locally
- gateway.enabled: Setting this to true will tell helm to setup a gateway and use Istio for routing to our application
Example
```
localDev: true
localRoute:
    source: /myapp/
    destination: /
    ...
green:
    enabled: true

blue:
    enabled: true
    ...
gateway:
    enabled: true
```
Open up your ingress-secrets.tpl and add a new if statement around the entire contents checking for the localDev variable

Example
```
{{ if not (default .Values.localDev false) }}
...
{{ end }}
```

The last file we need to change is your virtualservice.yaml. Istio will route all applications through the root of localhost, so if we have more than one application, we need to have Istio listen for those applications at http://localhost/myapp/ instead and internally route them to / for our api/website. You should see the following code block in your virtualservice.yaml:

Example

{{ if and .Values.blue.enabled .Values.green.enabled }}
- name: test
  match:
    - headers:
        {{ .Values.virtualService.headerName }}:
          exact: {{ .Values.virtualService.headerValue }}
  rewrite:
    uri: /
  route:
    - destination:
        port:
          number: 80
        host: {{ include "[project_name].fullname" . }}
        subset: test
{{ end }}

We need to swap that for this:

Example

{{ if and .Values.blue.enabled .Values.green.enabled }}
{{ if not (default .Values.localDev false) }}
- name: test
  match:
    - headers:
        {{ .Values.virtualService.headerName }}:
          exact: {{ .Values.virtualService.headerValue }}
  rewrite:
    uri: /
  route:
    - destination:
        port:
          number: 80
        host: {{ include [project_name].fullname" . }}
        subset: test
{{ else }}
- name: test
  match:
    - uri:
        prefix: {{ .Values.localRoute.source }}
  rewrite:
    uri: {{ .Values.localRoute.destination }}
  route:
    - destination:
        port:
          number: 80
        host: {{ include "[project_name].fullname" . }}
        subset: test
{{ end }}
{{ end }}

This new if statement is only triggered when localDev is set to true. Here we are adding in a uri prefix for Istio to match against and then supplying a rewrite which tells Istio what to rewrite that match to. For example, if I had /myapp/ as my .Values.localRoute.source and / as my .Values.localRoute.destination, when I go to http://localhost/myapp/, Istio would translate that into localhost/ for our app/website.

Be sure to replace [project_name] (including the []) with the name of your project.