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Configuring built-in listeners
For configuring built-in gateway listeners, use the MeshGateway resource.
These are Kong Mesh policies so if you are running on multi-zone they need to be created on the Global CP. See the dedicated section for using builtin gateways on multi-zone.
The MeshGateway resource specifies what network ports the gateway should listen on and how network traffic should be accepted.
A builtin gateway Dataplane can have exactly one MeshGateway resource bound to it.
This binding uses standard, tag-based Kong Mesh matching semantics:
Heads up! In previous versions of Kong Mesh, setting the
kuma.io/servicetag directly within aMeshGatewayInstanceresource was used to identify the service. However, this practice is deprecated and no longer recommended for security reasons since Kong Mesh version 2.7.0.We’ve automatically switched to generating the service name for you based on your
MeshGatewayInstanceresource name and namespace (format:{name}_{namespace}_svc).
A MeshGateway can have any number of listeners, where each listener represents an endpoint that can accept network traffic.
Note that the MeshGateway doesn’t specify which IP addresses are listened on; the Dataplane resource specifies that.
To configure a listener, you need to specify at least the port number and network protocol. Each listener may also have its own set of Kong Mesh tags so that Kong Mesh policy configuration can be targeted to specific listeners.
Hostname
An HTTP or HTTPS listener can also specify a hostname.
Note that listeners can share both port and protocol but differ on hostname.
This way routes can be attached to requests to specific hostnames but share
the port/protocol with other routes attached to other hostnames.
In the above example, the gateway proxy listens for HTTP protocol connections on TCP port 8080 but restricts the Host header to foo.example.com.
Above shows a MeshGateway resource with two HTTP listeners on the same port.
In this example, the gateway proxy will be configured to listen on port 8080, and accept HTTP requests for both hostnames.
Note that because each listener entry has its own Kong Mesh tags, policy can still be targeted to a specific listener.
Kong Mesh generates a set of tags for each listener by combining the tags from the listener, the MeshGateway and the Dataplane.
Kong Mesh matches policies against this set of combined tags.
Dataplane tags |
Listener tags | Final Tags |
|---|---|---|
| kuma.io/service=edge-gateway_default_svc | vhost=foo.example.com | kuma.io/service=edge-gateway_default_svc,vhost=foo.example.com |
| kuma.io/service=edge-gateway_default_svc | kuma.io/service=example,domain=example.com | kuma.io/service=example,domain=example.com |
| kuma.io/service=edge_default_svc,location=us | version=2 | kuma.io/service=edge_default_svc,location=us,version=2 |
TLS Termination
TLS sessions are terminated on a Gateway by specifying the “HTTPS” protocol, and providing a server certificate configuration. Below, the gateway listens on port 8443 and terminates TLS sessions.
The server certificate is provided through a Kong Mesh datasource reference, in this case naming a secret that must contain both the server certificate and the corresponding private key.
Server Certificate Secrets
A TLS server certificate secret is a collection of PEM objects in a Kong Mesh datasource (which may be a file, a Kong Mesh secret, or inline data).
There must be at least a private key and the corresponding TLS server certificate. The CA certificate chain may also be present, but if it is, the server certificate must be the first certificate in the secret.
Kong Mesh gateway supports serving both RSA and ECDSA server certificates.
To enable this support, generate two server certificate secrets and provide them both to the listener TLS configuration.
The kumactl tool supports generating simple, self-signed TLS server certificates. The script below shows how to do this.
Cross-mesh
The Mesh abstraction allows users
to encapsulate and isolate services
inside a kind of sub-mesh with its own CA.
With a cross-mesh MeshGateway,
you can expose the services of one Mesh
to other Meshes by defining an API with MeshHTTPRoutes.
All traffic remains inside the Kong Mesh data plane protected by mTLS.
All meshes involved in cross-mesh communication must have mTLS enabled.
To enable cross-mesh functionality for a MeshGateway listener,
set the crossMesh property.
Hostname
If the listener includes a hostname value,
the cross-mesh listener will be reachable
from all Meshes at this hostname and port.
In this case, the URL http://default.mesh:8080.
Otherwise it will be reachable at the host:
internal.<gateway-name>.<mesh-of-gateway-name>.mesh.
Without transparent proxy
If transparent proxy isn’t set up, you’ll have to add the listener explicitly as
an outbound to your Dataplane objects if you want to access it:
...
outbound:
- port: 8080
tags:
kuma.io/service: cross-mesh-gateway
kuma.io/mesh: default
Limitations
The only protocol supported is HTTP.
Like service to service traffic,
all traffic to the gateway is protected with mTLS
but appears to be HTTP traffic
to the applications inside the mesh.
In the future, this limitation may be relaxed.
There can be only one entry in selectors
for a MeshGateway with crossMesh: true.
