Examples¶
Below we will use YAML representation of the config protos and a running example of a service proxying HTTP from 127.0.0.1:10000 to 127.0.0.1:1234.
Static¶
A minimal fully static bootstrap config is provided below:
admin:
address:
socket_address: { address: 127.0.0.1, port_value: 9901 }
static_resources:
listeners:
- name: listener_0
address:
socket_address: { address: 127.0.0.1, port_value: 10000 }
filter_chains:
- filters:
- name: envoy.filters.network.http_connection_manager
typed_config:
"@type": type.googleapis.com/envoy.extensions.filters.network.http_connection_manager.v3.HttpConnectionManager
stat_prefix: ingress_http
codec_type: AUTO
route_config:
name: local_route
virtual_hosts:
- name: local_service
domains: ["*"]
routes:
- match: { prefix: "/" }
route: { cluster: some_service }
http_filters:
- name: envoy.filters.http.router
clusters:
- name: some_service
connect_timeout: 0.25s
type: STATIC
lb_policy: ROUND_ROBIN
load_assignment:
cluster_name: some_service
endpoints:
- lb_endpoints:
- endpoint:
address:
socket_address:
address: 127.0.0.1
port_value: 1234
Mostly static with dynamic EDS¶
A bootstrap config that continues from the above example with dynamic endpoint discovery via an EDS gRPC management server listening on 127.0.0.1:5678 is provided below:
admin:
address:
socket_address: { address: 127.0.0.1, port_value: 9901 }
static_resources:
listeners:
- name: listener_0
address:
socket_address: { address: 127.0.0.1, port_value: 10000 }
filter_chains:
- filters:
- name: envoy.filters.network.http_connection_manager
typed_config:
"@type": type.googleapis.com/envoy.extensions.filters.network.http_connection_manager.v3.HttpConnectionManager
stat_prefix: ingress_http
codec_type: AUTO
route_config:
name: local_route
virtual_hosts:
- name: local_service
domains: ["*"]
routes:
- match: { prefix: "/" }
route: { cluster: some_service }
http_filters:
- name: envoy.filters.http.router
clusters:
- name: some_service
connect_timeout: 0.25s
lb_policy: ROUND_ROBIN
type: EDS
eds_cluster_config:
eds_config:
resource_api_version: V3
api_config_source:
api_type: GRPC
transport_api_version: V3
grpc_services:
- envoy_grpc:
cluster_name: xds_cluster
- name: xds_cluster
connect_timeout: 0.25s
type: STATIC
lb_policy: ROUND_ROBIN
typed_extension_protocol_options:
envoy.extensions.upstreams.http.v3.HttpProtocolOptions:
"@type": type.googleapis.com/envoy.extensions.upstreams.http.v3.HttpProtocolOptions
explicit_http_config:
http2_protocol_options:
connection_keepalive:
interval: 30s
timeout: 5s
upstream_connection_options:
# configure a TCP keep-alive to detect and reconnect to the admin
# server in the event of a TCP socket half open connection
tcp_keepalive: {}
load_assignment:
cluster_name: xds_cluster
endpoints:
- lb_endpoints:
- endpoint:
address:
socket_address:
address: 127.0.0.1
port_value: 5678
Notice above that xds_cluster is defined to point Envoy at the management server. Even in an otherwise completely dynamic configurations, some static resources need to be defined to point Envoy at its xDS management server(s).
It’s important to set appropriate TCP Keep-Alive options
in the tcp_keepalive block. This will help detect TCP half open connections to the xDS management
server and re-establish a full connection.
In the above example, the EDS management server could then return a proto encoding of a DiscoveryResponse:
version_info: "0"
resources:
- "@type": type.googleapis.com/envoy.config.endpoint.v3.ClusterLoadAssignment
cluster_name: some_service
endpoints:
- lb_endpoints:
- endpoint:
address:
socket_address:
address: 127.0.0.1
port_value: 1234
The versioning and type URL scheme that appear above are explained in more detail in the streaming gRPC subscription protocol documentation.
Dynamic¶
A fully dynamic bootstrap configuration, in which all resources other than those belonging to the management server are discovered via xDS is provided below:
admin:
address:
socket_address: { address: 127.0.0.1, port_value: 9901 }
dynamic_resources:
lds_config:
resource_api_version: V3
api_config_source:
api_type: GRPC
transport_api_version: V3
grpc_services:
- envoy_grpc:
cluster_name: xds_cluster
cds_config:
resource_api_version: V3
api_config_source:
api_type: GRPC
transport_api_version: V3
grpc_services:
- envoy_grpc:
cluster_name: xds_cluster
static_resources:
clusters:
- name: xds_cluster
connect_timeout: 0.25s
type: STATIC
lb_policy: ROUND_ROBIN
typed_extension_protocol_options:
envoy.extensions.upstreams.http.v3.HttpProtocolOptions:
"@type": type.googleapis.com/envoy.extensions.upstreams.http.v3.HttpProtocolOptions
explicit_http_config:
http2_protocol_options:
# Configure an HTTP/2 keep-alive to detect connection issues and reconnect
# to the admin server if the connection is no longer responsive.
connection_keepalive:
interval: 30s
timeout: 5s
load_assignment:
cluster_name: xds_cluster
endpoints:
- lb_endpoints:
- endpoint:
address:
socket_address:
address: 127.0.0.1
port_value: 5678
The management server could respond to LDS requests with:
version_info: "0"
resources:
- "@type": type.googleapis.com/envoy.config.listener.v3.Listener
name: listener_0
address:
socket_address:
address: 127.0.0.1
port_value: 10000
filter_chains:
- filters:
- name: envoy.filters.network.http_connection_manager
typed_config:
"@type": type.googleapis.com/envoy.extensions.filters.network.http_connection_manager.v3.HttpConnectionManager
stat_prefix: ingress_http
codec_type: AUTO
rds:
route_config_name: local_route
config_source:
resource_api_version: V3
api_config_source:
api_type: GRPC
transport_api_version: V3
grpc_services:
- envoy_grpc:
cluster_name: xds_cluster
http_filters:
- name: envoy.filters.http.router
The management server could respond to RDS requests with:
version_info: "0"
resources:
- "@type": type.googleapis.com/envoy.config.route.v3.RouteConfiguration
name: local_route
virtual_hosts:
- name: local_service
domains: ["*"]
routes:
- match: { prefix: "/" }
route: { cluster: some_service }
The management server could respond to CDS requests with:
version_info: "0"
resources:
- "@type": type.googleapis.com/envoy.config.cluster.v3.Cluster
name: some_service
connect_timeout: 0.25s
lb_policy: ROUND_ROBIN
type: EDS
eds_cluster_config:
eds_config:
resource_api_version: V3
api_config_source:
api_type: GRPC
transport_api_version: V3
grpc_services:
- envoy_grpc:
cluster_name: xds_cluster
The management server could respond to EDS requests with:
version_info: "0"
resources:
- "@type": type.googleapis.com/envoy.config.endpoint.v3.ClusterLoadAssignment
cluster_name: some_service
endpoints:
- lb_endpoints:
- endpoint:
address:
socket_address:
address: 127.0.0.1
port_value: 1234
Special YAML usage¶
When loading YAML configuration, the Envoy loader will interpret map keys tagged with !ignore specially, and omit them entirely from the native configuration tree. Ordinarily, the YAML stream must adhere strictly to the proto schemas defined for Envoy configuration. This allows content to be declared that is explicitly handled as a non-represented type.
This lets you split your file into two parts: one in which we have YAML content not subject to parsing according to the schema and another part that is parsed. YAML anchors in the first part may be referenced by aliases in the second part. This mechanism can simplify setups that need to re-use or dynamically generate configuration fragments.
See the following example:
!ignore dynamic_sockets:
- &admin_address {address: 127.0.0.1, port_value: 9901}
- &listener_address {address: 127.0.0.1, port_value: 10000}
- &lb_address {address: 127.0.0.1, port_value: 1234}
admin:
address:
socket_address: *admin_address
static_resources:
listeners:
- name: listener_0
address:
socket_address: *listener_address
filter_chains:
- filters:
- name: envoy.filters.network.http_connection_manager
typed_config:
"@type": type.googleapis.com/envoy.extensions.filters.network.http_connection_manager.v3.HttpConnectionManager
stat_prefix: ingress_http
codec_type: AUTO
route_config:
name: local_route
virtual_hosts:
- name: local_service
domains: ["*"]
routes:
- match: {prefix: "/"}
route: {cluster: some_service}
http_filters:
- name: envoy.filters.http.router
clusters:
- name: some_service
connect_timeout: 0.25s
type: STATIC
lb_policy: ROUND_ROBIN
load_assignment:
cluster_name: some_service
endpoints:
- lb_endpoints:
- endpoint:
address:
socket_address: *lb_address
Warning
If you parse Envoy YAML configuration using external loaders, you may need to inform these loaders about the !ignore tag. Compliant YAML loaders will typically expose an interface to allow you to choose how to handle a custom tag.
For example, this will instruct PyYAML to treat an ignored node as a simple scalar when loading:
yaml.SafeLoader.add_constructor('!ignore', yaml.loader.SafeConstructor.construct_scalar)
Alternatively, this is how Envoy registers the !ignore tag in config validation.