Protocol Selection
Istio supports proxying all TCP traffic by default, but in order to provide additional capabilities, such as routing and rich metrics, the protocol must be determined. This can be done automatically or explicitly specified.
Manual protocol selection
Protocols can be specified manually in the Service definition.
This can be configured in two ways:
- By the name of the port:
name: <protocol>[-<suffix>]
. - In Kubernetes 1.18+, by the
appProtocol
field:appProtocol: <protocol>
.
The following protocols are supported:
grpc
grpc-web
http
http2
https
mongo
mysql
*redis
*tcp
tls
udp
* These protocols are disabled by default to avoid accidentally enabling experimental features. To enable them, configure the corresponding Pilot environment variables.
Below is an example of a Service that defines a mysql
port by appProtocol
and an http
port by name:
kind: Service
metadata:
name: myservice
spec:
ports:
- number: 3306
name: database
appProtocol: mysql
- number: 80
name: http-web
Automatic protocol selection
Istio can automatically detect HTTP and HTTP/2 traffic. If the protocol cannot automatically be determined, traffic will be treated as plain TCP traffic.
This feature is enabled by default. It can be turned off by providing the following install options:
--set values.pilot.enableProtocolSniffingForOutbound=false
to disable protocol detection for outbound listeners whose port protocol is not specified or unsupported.--set values.pilot.enableProtocolSniffingForInbound=false
to disable protocol detection for inbound listeners whose port protocol is not specified or unsupported.