Dynamic forward proxy common configuration¶

This documentation is for the Envoy v3 API.

As of Envoy v1.18 the v2 API has been removed and is no longer supported.

If you are upgrading from v2 API config you may wish to view the v2 API documentation:

config/common/dynamic_forward_proxy/v2alpha/dns_cache.proto

extensions.common.dynamic_forward_proxy.v3.DnsCacheCircuitBreakers¶

[extensions.common.dynamic_forward_proxy.v3.DnsCacheCircuitBreakers proto]

Configuration of circuit breakers for resolver.

{
  "max_pending_requests": "{...}"
}

max_pending_requests: (UInt32Value) The maximum number of pending requests that Envoy will allow to the resolver. If not specified, the default is 1024.

extensions.common.dynamic_forward_proxy.v3.DnsCacheConfig¶

[extensions.common.dynamic_forward_proxy.v3.DnsCacheConfig proto]

Configuration for the dynamic forward proxy DNS cache. See the architecture overview for more information.

{
  "name": "...",
  "dns_lookup_family": "...",
  "dns_refresh_rate": "{...}",
  "host_ttl": "{...}",
  "max_hosts": "{...}",
  "dns_failure_refresh_rate": "{...}",
  "dns_cache_circuit_breaker": "{...}",
  "use_tcp_for_dns_lookups": "...",
  "dns_resolution_config": "{...}",
  "typed_dns_resolver_config": "{...}",
  "preresolve_hostnames": [],
  "dns_query_timeout": "{...}"
}

name: (string, REQUIRED) The name of the cache. Multiple named caches allow independent dynamic forward proxy configurations to operate within a single Envoy process using different configurations. All configurations with the same name must otherwise have the same settings when referenced from different configuration components. Configuration will fail to load if this is not the case.

dns_lookup_family: (config.cluster.v3.Cluster.DnsLookupFamily) The DNS lookup family to use during resolution.

dns_refresh_rate

(Duration) The DNS refresh rate for unresolved DNS hosts. If not specified defaults to 60s.

The refresh rate is rounded to the closest millisecond, and must be at least 1ms.

Once a host has been resolved, the refresh rate will be the DNS TTL, capped at a minimum of 5s.

host_ttl: (Duration) The TTL for hosts that are unused. Hosts that have not been used in the configured time interval will be purged. If not specified defaults to 5m.

max_hosts: (UInt32Value) The maximum number of hosts that the cache will hold. If not specified defaults to 1024.

dns_failure_refresh_rate: (config.cluster.v3.Cluster.RefreshRate) If the DNS failure refresh rate is specified, this is used as the cache’s DNS refresh rate when DNS requests are failing. If this setting is not specified, the failure refresh rate defaults to the dns_refresh_rate.

dns_cache_circuit_breaker: (extensions.common.dynamic_forward_proxy.v3.DnsCacheCircuitBreakers) The config of circuit breakers for resolver. It provides a configurable threshold. Envoy will use dns cache circuit breakers with default settings even if this value is not set.

use_tcp_for_dns_lookups: (bool) Always use TCP queries instead of UDP queries for DNS lookups. This field is deprecated in favor of dns_resolution_config which aggregates all of the DNS resolver configuration in a single message.

dns_resolution_config: (config.core.v3.DnsResolutionConfig) DNS resolution configuration which includes the underlying dns resolver addresses and options. This field is deprecated in favor of typed_dns_resolver_config.

typed_dns_resolver_config

(config.core.v3.TypedExtensionConfig) DNS resolver type configuration extension. This extension can be used to configure c-ares, apple, or any other DNS resolver types and the related parameters. For example, an object of CaresDnsResolverConfig can be packed into this typed_dns_resolver_config. This configuration replaces the dns_resolution_config configuration. During the transition period when both dns_resolution_config and typed_dns_resolver_config exists, when typed_dns_resolver_config is in place, Envoy will use it and ignore dns_resolution_config. When typed_dns_resolver_config is missing, the default behavior is in place.

Tip

This extension category has the following known extensions:

preresolve_hostnames: (repeated config.core.v3.SocketAddress) Hostnames that should be preresolved into the cache upon creation. This might provide a performance improvement, in the form of cache hits, for hostnames that are going to be resolved during steady state and are known at config load time.

dns_query_timeout: (Duration) The timeout used for DNS queries. This timeout is independent of any timeout and retry policy used by the underlying DNS implementation (e.g., c-areas and Apple DNS) which are opaque. Setting this timeout will ensure that queries succeed or fail within the specified time frame and are then retried using the standard refresh rates. Defaults to 5s if not set.