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MeshExternalService
This resource is experimental!
This resource allows services running inside the mesh to consume services that are not part of the mesh.
The MeshExternalService
resource allows you to declare external resources instead of relying on MeshPassthrough or passthrough mode.
What is the difference between MeshPassthrough
and MeshExternalService
?
The main difference is that MeshExternalService
assigns a custom domain and can be targeted by policies.
MeshPassthrough
does not alter the address of the original host and cannot be targeted by policies.
Currently you can not configure granular MeshTrafficPermission for MeshExternalService. You can only enable or disable whole traffic to MeshExternalService from Mesh by Mesh resource configuration. More on this in Controlling MeshExternalService access from Mesh section.
Configuration
Match
This section specifies the rules for matching traffic that will be routed to external resources defined in endpoints
section.
The only type
supported is HostnameGenerator
(this field is optional so can be omitted) and it means that it will match traffic directed to a hostname created by the hostname generator.
The port
field when omitted means that all traffic will be matched.
Protocols that are supported are: tcp
, grpc
, http
, http2
.
match:
type: HostnameGenerator # optional
port: 4244
protocol: tcp
Endpoints
This section specifies the destination of the matched traffic. It’s possible to define IPs, DNS names and unix domain sockets.
endpoints:
- address: 1.1.1.1
port: 12345
- address: example.com
port: 80
- address: unix:///tmp/example.sock
TLS
This section describes the TLS and verification behaviour.
TLS origination happens on the sidecar, so if your application is already using TLS you might want to use MeshPassthrough.
You can define TLS version requirements, option to allow renegotiation, verification of SNI, SAN, custom CA and client certificate and key for server verification.
To disable parts of the verification you can set different mode
- SkipSAN
, SkipCA
, SkipAll
, Secured
(default).
tls:
version:
min: TLS12
max: TLS13
allowRenegotiation: false
verification:
mode: SkipCA
serverName: "example.com"
subjectAltNames:
- type: Exact
value: example.com
- type: Prefix
value: "spiffe://example.local/ns/local"
caCert:
inline: dGVzdA==
clientCert:
secret: "123"
clientKey:
secret: "456"
When TLS is enabled but caCert
is not set, the sidecar uses the autodetected OS-specific CA.
The user can override the default CA by setting the path in the environment variable KUMA_DATAPLANE_RUNTIME_DYNAMIC_SYSTEM_CA_PATH
for the sidecar.
DNS setup
To be able to access MeshExternalService
via a hostname you need to define a HostnameGenerator
with a meshExternalService
selector.
In the future release a default HostnameGenerator
will be provided.
Once a HostnameGenerator
and a MeshExternalService
is in place the following will happen:
- a hostname (or multiple hostnames if there are many
HostnameGenerators
matching) are generated using the specified templates - a VIP is allocated from
242.0.0.0/8
range (can be changed byKUMA_IPAM_MESH_EXTERNAL_SERVICE_CIDR
environment variable) - Envoy cluster is created which will use endpoints defined in
spec.endpoints
as the cluster endpoints
Do not hijack original addresses like httpbin.com (the way it was done with External Service). Hijacking the original address is like performing a man-in-the-middle attack so there is a high chance of something breaking. If you need to transparently pass traffic through the Mesh without modifying it use MeshPassthrough.
For accessing entire subdomains, take a look at Wildcard DNS matching in MeshPassthrough.
Universal mode without Transparent Proxy
MeshExternalService
works on Universal mode without Transparent Proxy, but you need to manually define an outbound that targets the correct MeshExternalService
:
networking:
outbound:
- port: 8080
backendRef:
kind: MeshExternalService
name: mes-http
The whole command will look something like this:
./kuma-dp run \
--cp-address=https://localhost:5678/ \
--dns-enabled=false \
--dataplane-token-file=token-file \
--dataplane="
type: Dataplane
mesh: default
name: example
networking:
address: 127.0.0.1
inbound:
- port: 16379
servicePort: 26379
serviceAddress: 127.0.0.1
tags:
kuma.io/service: example
kuma.io/protocol: tcp
outbound:
- port: 8080
backendRef:
kind: MeshExternalService
name: mes-http
admin:
port: 9901"
Controlling MeshExternalService access from Mesh
At this moment you cannot configure MeshTrafficPermission for MeshExternalService. But you can configure access to all external services on Mesh level. For example, you can disable outgoing traffic to all MeshExternalServices:
apiVersion: kuma.io/v1alpha1
kind: Mesh
metadata:
name: default
spec:
routing:
defaultForbidMeshExternalServiceAccess: true
Examples
TCP examples use https://tcpbin.com/ service which is a TCP echo service, check out the website for more details. HTTP examples use https://httpbin.org/ service which is a website for inspecting and debugging HTTP requests. GRPC examples use https://grpcbin.test.k6.io/ service which is a gRPC Request & Response Service. You can use grpcurl as a client, it is available in netshoot debug image alongside other tools used in later sections.
For the examples below we’re using a single-zone deployment and the following HostnameGenerator
:
apiVersion: kuma.io/v1alpha1
kind: HostnameGenerator
metadata:
name: example
namespace: kuma-system
labels:
kuma.io/mesh: default
spec:
selector:
meshExternalService:
matchLabels:
kuma.io/origin: zone
template: "{{ .DisplayName }}.svc.meshext.local"
If you’re in multi-zone deployment and you’re applying resources on the global control plane you’d need a second HostnameGenerator
with matchLabels: kuma.io/origin: global
for resources applied on the global Control Plane and to adjust the URLs accordingly to match the template.
TCP
This is a simple example of accessing tcpbin.com
service without TLS that echos back bytes sent to it.
apiVersion: kuma.io/v1alpha1
kind: MeshExternalService
metadata:
name: mes-tcp
namespace: kuma-system
labels:
kuma.io/mesh: default
spec:
match:
type: HostnameGenerator
port: 4242
protocol: tcp
endpoints:
- address: tcpbin.com
port: 4242
Running this should result in printing ‘echo this’ in the terminal:
echo 'echo this' | nc -q 3 mes-tcp.svc.meshext.local 4242
TCP with TLS
This example builds up on the previous example adding TLS verification with default system CA.
Notice that we’re using a TLS port 4243
.
apiVersion: kuma.io/v1alpha1
kind: MeshExternalService
metadata:
name: mes-tcp-tls
namespace: kuma-system
labels:
kuma.io/mesh: default
spec:
match:
type: HostnameGenerator
port: 4243
protocol: tcp
endpoints:
- address: tcpbin.com
port: 4243
tls:
enabled: true
verification:
serverName: tcpbin.com
Running this should result in printing ‘echo this’ in the terminal:
echo 'echo this' | nc -q 3 mes-tcp-tls.svc.meshext.local 4243
TCP with mTLS
This example builds up on the previous example adding client cert and key.
Notice that we’re using an mTLS port 4244
.
In a real world scenario you should use secret
and refer to it through it’s name and store sensitive information as a Kubernetes secret instead of using inline
.
This example is purposefully simplified to make it easy to try out.
apiVersion: kuma.io/v1alpha1
kind: MeshExternalService
metadata:
name: mes-tcp-mtls
namespace: kuma-system
labels:
kuma.io/mesh: default
spec:
match:
type: HostnameGenerator
port: 4244
protocol: tcp
endpoints:
- address: tcpbin.com
port: 4244
tls:
enabled: true
verification:
serverName: tcpbin.com
clientCert:
inline: LS0tLS1CRUdJTiBDRVJUSUZJQ0FURS0tLS0tCk1JSURaVENDQWsyZ0F3SUJBZ0lCS2pBTkJna3Foa2lHOXcwQkFRc0ZBRENCaXpFTE1Ba0dBMVVFQmhNQ1ZWTXgKQ3pBSkJnTlZCQWdNQWtOQk1SWXdGQVlEVlFRSERBMVRZVzRnUm5KaGJtTnBjMk52TVE4d0RRWURWUVFLREFaMApZM0JpYVc0eEREQUtCZ05WQkFzTUEyOXdjekVUTUJFR0ExVUVBd3dLZEdOd1ltbHVMbU52YlRFak1DRUdDU3FHClNJYjNEUUVKQVJZVWFHRnljbmxpWVdka2FVQm5iV0ZwYkM1amIyMHdIaGNOTWpRd05qRTBNRGt4T1RVMldoY04KTWpRd05qRTFNRGt4T1RVMldqQWNNUm93R0FZRFZRUUREQkYwWTNCaWFXNHVZMjl0TFdOc2FXVnVkRENDQVNJdwpEUVlKS29aSWh2Y05BUUVCQlFBRGdnRVBBRENDQVFvQ2dnRUJBS3VZVHo0UzRIcEtvc05FRWcxbDFOT3ZORjZtCkxEN0o4d1ZsdFVSd2JXNDNaM2JJVmNOUFVuNjdkTVpEUUpRcVU2Z05kRTg0eXBvQTUxbXpqcC9IeGZZY2c1cEMKZXFyK1RtVDV1S3UyME8ycDZmYXhrZDlYUHpmWXUybE1QM0tROU9DbmpNbEIwQkFiNUNpTklRTmIwMUtheDhCOAphT0Z1a3VYKzdheWhRRXFxRHJ5d0d6Q0hJc2ppU3lDVHdRRXhiQVJTY1BGOW5XaDlHZVRERGlRSEtKUXFVOEpnClVoRGMzQUdjdlI2c0pEZFZ1RXl2UndrNVcrTFhoNktPQVAwNHEwaGF2OXFiaXNaZitXNVNRMDFvbXIzRGhzSTQKZkx2c05oN0I5UGpqaVNnV09hQ3F4bEdCSDNJdUJtWXgxR1k5RCtia0VJazVsVkZ4WC92d0N1SmhzRlVDQXdFQQpBYU5DTUVBd0hRWURWUjBPQkJZRUZGSDRnN3V3OFdzTUIwYlRKNld2NFV5NGtlME1NQjhHQTFVZEl3UVlNQmFBCkZPTHVNb3dCU0FaZlY1djgyTG1sYUlJT3ZVL0RNQTBHQ1NxR1NJYjNEUUVCQ3dVQUE0SUJBUUJmYzlxQWFNUjcKbTEzMlZoSk52M0dVOXNZMytMUHN6dkJMMkYyeGw5U1AwVlA3cG9Hd3ZvSnJ0cXdGR0FFaGtibzNCUkhvZTBTMwpVUkdtTlNjWlpTMVdkQllBSVdvdkJKbFNhakxqVDVWNGNrc0FXVjZ3djlmaE9XcXFTSmpVaEwwZ3FkWkp2NDNoCkFnVnZGeXQrUHF4NmpZMHBhUkp6TS9OM1pkTFBDTkZiMVlIMzE3Q0FyQlV1R2xWQzJzRDNJd0lEK0YzczdhOEcKQ2FSb0VnWGpNdEZVcnBJN2RqaTVSeHlENE9Ma2o3bmw0aXk3anJDWlAvRitKbys4dEo3NVI4VW8xeU8zSXorOApTanFkYWdwT3RKQzdEV1pyNlNYOW85a0lsTUl4SEhITmN0RElteXB6SytmWFpaZUFnTVVTSE1kWCsrd0xNTVdrCnZ0Tm1vUFZVVHJvNwotLS0tLUVORCBDRVJUSUZJQ0FURS0tLS0tCgo=
clientKey:
inline: 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
Running this should result in printing ‘echo this’ in the terminal:
echo 'echo this' | nc -q 3 mes-tcp-mtls.svc.meshext.local 4244
HTTP
This is a simple example using plaintext HTTP.
apiVersion: kuma.io/v1alpha1
kind: MeshExternalService
metadata:
name: mes-http
namespace: kuma-system
labels:
kuma.io/mesh: default
spec:
match:
type: HostnameGenerator
port: 80
protocol: http
endpoints:
- address: httpbin.org
port: 80
Running this should result in printing httpbin.org HTML in the terminal:
curl -s http://mes-http.svc.meshext.local
HTTPS
This example builds up on the previous example adding TLS verification with default system CA.
apiVersion: kuma.io/v1alpha1
kind: MeshExternalService
metadata:
name: mes-https
namespace: kuma-system
labels:
kuma.io/mesh: default
spec:
match:
type: HostnameGenerator
port: 80
protocol: http
endpoints:
- address: httpbin.org
port: 443
tls:
enabled: true
verification:
serverName: httpbin.org
Running this should result in printing httpbin.org HTML in the terminal:
curl http://mes-https.svc.meshext.local
gRPC
This is a simple example using plaintext gRPC.
apiVersion: kuma.io/v1alpha1
kind: MeshExternalService
metadata:
name: mes-grpc
namespace: kuma-system
labels:
kuma.io/mesh: default
spec:
match:
type: HostnameGenerator
port: 9000
protocol: grpc
endpoints:
- address: grpcbin.test.k6.io
port: 9000
Running this should result in printing grpcbin.test.k6.io available methods:
grpcurl -plaintext -v mes-grpc.svc.meshext.local:9000 list
gRPCS
This example builds up on the previous example adding TLS verification with default system CA.
Notice that we’re using a different port 9001
.
apiVersion: kuma.io/v1alpha1
kind: MeshExternalService
metadata:
name: mes-grpcs
namespace: kuma-system
labels:
kuma.io/mesh: default
spec:
match:
type: HostnameGenerator
port: 9001
protocol: grpc
endpoints:
- address: grpcbin.test.k6.io
port: 9001
tls:
enabled: true
verification:
serverName: grpcbin.test.k6.io
Running this should result in printing grpcbin.test.k6.io available methods:
grpcurl -plaintext -v mes-grpcs.svc.meshext.local:9001 list # this is using plaintext because Envoy is doing TLS origination