consul/website/content/docs/k8s/connect/terminating-gateways.mdx

---
layout: docs
page_title: Terminating Gateways - Kubernetes
sidebar_title: Terminating Gateways
description: Configuring Terminating Gateways on Kubernetes
---

# Terminating Gateways on Kubernetes

-> 1.9.0+: This feature is available in Consul versions 1.9.0 and higher

~> This topic requires familiarity with [Terminating Gateways](/docs/connect/terminating-gateway).

Adding a terminating gateway is a multi-step process:

- Update the helm chart with terminating gateway config options
- Deploy the helm chart
- Access the Consul agent
- Register external services with Consul

## Update the helm chart with terminating gateway config options

Minimum required Helm options:

```yaml
global:
  name: consul
connectInject:
  enabled: true
controller:
  enabled: true
terminatingGateways:
  enabled: true
```

## Deploying the helm chart

Ensure you have the latest consul-helm chart and install Consul via helm using the following
[guide](/docs/k8s/installation/install#installing-consul) while being sure to provide the yaml configuration
as previously discussed.

## Accessing the Consul agent

You can access the Consul server directly from your host via `kubectl port-forward`. This is helpful for interacting with your Consul UI locally as well as to validate connectivity of the application.

```shell-session
$ kubectl port-forward consul-server-0 8500 &
```

If TLS is enabled use port 8501:

```shell-session
$ kubectl port-forward consul-server-0 8501 &
```

-> Be sure the latest consul binary is installed locally on your host.
[https://releases.hashicorp.com/consul/](https://releases.hashicorp.com/consul/)

```shell-session
$ export CONSUL_HTTP_ADDR=http://localhost:8500
```

If TLS is enabled set:

```shell-session
$ export CONSUL_HTTP_ADDR=https://localhost:8501
$ export CONSUL_HTTP_SSL_VERIFY=false
```

If ACLs are enabled also set:

```shell-session
$ export CONSUL_HTTP_TOKEN=$(kubectl get secret consul-bootstrap-acl-token -o jsonpath={.data.token} | base64 -D)
```

## Register external services with Consul

Registering the external services with Consul is a multi-step process:

- Register external services with Consul
- Update the terminating gateway ACL token if ACLs are enabled
- Create a [`TerminatingGateway`](/docs/connect/config-entries/terminating-gateway) resource to configure the terminating gateway
- Create a [`ServiceIntentions`](/docs/connect/config-entries/service-intentions) resource to allow access from services in the mesh to external service
- Define upstream annotations for any services that need to talk to the external services

### Register external services with Consul

Create a sample external service and register it with Consul.

```json
{
  "Node": "legacy_node",
  "Address": "example.com",
  "NodeMeta": {
    "external-node": "true",
    "external-probe": "true"
  },
  "Service": {
    "ID": "example-https",
    "Service": "example-https",
    "Port": 443
  }
}
```

Register the external service with Consul:

```shell-session
$ curl --request PUT --data @external.json -k $CONSUL_HTTP_ADDR/v1/catalog/register
true
```

If ACLs and TLS are enabled :

```shell-session
$ curl --request PUT --header "X-Consul-Token: $CONSUL_HTTP_TOKEN" --data @external.json -k $CONSUL_HTTP_ADDR/v1/catalog/register
true
```

### Update terminating gateway ACL token if ACLs are enabled

If ACLs are enabled, update the terminating gateway acl token to have `service: write` permissions on all of the services
being represented by the gateway:

- Create a new policy that includes these permissions
- Update the existing token to include the new policy

~> The CLI command should be run with the `-merge-policies`, `-merge-roles` and `-merge-service-identities` so
nothing is removed from the terminating gateway token

```hcl
service "example-https" {
  policy = "write"
}
```

```shell-session
$ consul acl policy create -name "example-https-write-policy" -rules @write-policy.hcl
ID:           xxxxxxxxxxxxxxx
Name:         example-https-write-policy
Description:
Datacenters:
Rules:
service "example-https" {
  policy = "write"
}
```

Now fetch the id of the terminating gateway token

```shell-session
consul acl token list | grep -B 6 -- "- terminating-gateway-terminating-gateway-token" | grep AccessorID

AccessorID:       <token id>
```

Update the terminating gateway acl token with the new policy

```shell-session
$ consul acl token update -id <token-id> -policy-name example-https-write-policy -merge-policies -merge-roles -merge-service-identities
AccessorID:       <token id>
SecretID:         <secret id>
Description:      terminating-gateway-terminating-gateway-token Token
Local:            true
Create Time:      2021-01-08 21:18:47.957450486 +0000 UTC
Policies:
   63bf1d9b-a87d-8672-ddcb-d25e2d88adb8 - terminating-gateway-terminating-gateway-token
   f63d1ae6-ffe7-44bd-bf7a-704a86939a63 - example-https-write-policy
```

### Create the configuration entry for the terminating gateway

Once the tokens have been updated, create the [TerminatingGateway](/docs/connect/config-entries/terminating-gateway)
resource to configure the terminating gateway:

```hcl
apiVersion: consul.hashicorp.com/v1alpha1
kind: TerminatingGateway
metadata:
  name: terminating-gateway
spec:
  services:
    - name: example-https
      caFile: /etc/ssl/cert.pem
```

~> If TLS is enabled a `caFile` must be provided, it must point to the system trust store of the terminating gateway
container (`/etc/ssl/cert.pem`).

Apply the `TerminatingGateway` resource with `kubectl apply`:

```shell-session
$ kubectl apply -f terminating-gateway.yaml
```

If using ACLs and TLS, create a [`ServiceIntentions`](/docs/connect/config-entries/service-intentions) resource to allow access from services in the mesh to the external service

```yaml
apiVersion: consul.hashicorp.com/v1alpha1
kind: ServiceIntentions
metadata:
  name: example-https
spec:
  destination:
    name: example-https
  sources:
    - name: static-client
      action: allow
```

Apply the `ServiceIntentions` resource with `kubectl apply`:

```shell-session
$ kubectl apply -f service-intentions.yaml
```

### Define the external services as upstreams for services in the mesh

Finally define and deploy the external services as upstreams for the internal mesh services that wish to talk to them.
An example deployment is provided which will serve as a static client for the terminating gateway service.

```yaml
apiVersion: v1
kind: ServiceAccount
metadata:
  name: static-client
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: static-client
spec:
  replicas: 1
  selector:
    matchLabels:
      app: static-client
  template:
    metadata:
      name: static-client
      labels:
        app: static-client
      annotations:
        'consul.hashicorp.com/connect-inject': 'true'
        'consul.hashicorp.com/connect-service-upstreams': 'example-https:1234'
    spec:
      containers:
        # This name will be the service name in Consul.
        - name: static-client
          image: tutum/curl:latest
          command: ['/bin/sh', '-c', '--']
          args: ['while true; do sleep 30; done;']
        # If ACLs are enabled, the serviceAccountName must match the Consul service name.
      serviceAccountName: static-client
```

Run the service via `kubectl apply`:

```shell-session
$ kubectl apply -f static-client.yaml
```

Wait for the service to be ready:

```shell-session
$ kubectl rollout status deploy static-client --watch
deployment "static-client" successfully rolled out
```

You can verify connectivity of the static-client and terminating gateway via a curl command:

```shell-session
$ kubectl exec deploy/static-client -- curl -vvvs -H "Host: example-https.com" http://localhost:1234/
```