Destination Rule

Settings common to both HTTP and TCP upstream connections.

HTTP connection pool settings.

Maximum number of pending HTTP requests to a destination. Default 1024.

Maximum number of requests to a backend. Default 1024.

Maximum number of requests per connection to a backend. Setting this parameter to 1 disables keep alive. Default 0, meaning “unlimited”, up to 2^29.

Maximum number of retries that can be outstanding to all hosts in a cluster at a given time. Defaults to 1024.

The idle timeout for upstream connection pool connections. The idle timeout is defined as the period in which there are no active requests. If not set, there is no idle timeout. When the idle timeout is reached the connection will be closed. Note that request based timeouts mean that HTTP/2 PINGs will not keep the connection alive. Applies to both HTTP1.1 and HTTP2 connections.

Specify if http1.1 connection should be upgraded to http2 for the associated destination.

Maximum number of HTTP1 /TCP connections to a destination host. Default 1024.

TCP connection timeout.

If set then set SO_KEEPALIVE on the socket to enable TCP Keepalives.

Maximum number of keepalive probes to send without response before deciding the connection is dead. Default is to use the OS level configuration (unless overridden, Linux defaults to 9.)

The time duration a connection needs to be idle before keep-alive probes start being sent. Default is to use the OS level configuration (unless overridden, Linux defaults to 7200s (ie 2 hours.)

The time duration between keep-alive probes. Default is to use the OS level configuration (unless overridden, Linux defaults to 75s.)

REQUIRED. The name of a service from the service registry. Service names are looked up from the platform’s service registry (e.g., Kubernetes services, Consul services, etc.) and from the hosts declared by ServiceEntries. Rules defined for services that do not exist in the service registry will be ignored.

Note for Kubernetes users: When short names are used (e.g. “reviews” instead of “reviews.default.svc.cluster.local”), Istio will interpret the short name based on the namespace of the rule, not the service. A rule in the “default” namespace containing a host “reviews” will be interpreted as “reviews.default.svc.cluster.local”, irrespective of the actual namespace associated with the reviews service. To avoid potential misconfigurations, it is recommended to always use fully qualified domain names over short names.

Note that the host field applies to both HTTP and TCP services.

Traffic policies to apply (load balancing policy, connection pool sizes, outlier detection).

One or more named sets that represent individual versions of a service. Traffic policies can be overridden at subset level.

A list of namespaces to which this destination rule is exported. The resolution of a destination rule to apply to a service occurs in the context of a hierarchy of namespaces. Exporting a destination rule allows it to be included in the resolution hierarchy for services in other namespaces. This feature provides a mechanism for service owners and mesh administrators to control the visibility of destination rules across namespace boundaries.

If no namespaces are specified then the destination rule is exported to all namespaces by default.

The value “.” is reserved and defines an export to the same namespace that the destination rule is declared in. Similarly, the value “*” is reserved and defines an export to all namespaces.

NOTE: in the current release, the exportTo value is restricted to “.” or “*” (i.e., the current namespace or all namespaces).

The minimum number of virtual nodes to use for the hash ring. Defaults to 1024. Larger ring sizes result in more granular load distributions. If the number of hosts in the load balancing pool is larger than the ring size, each host will be assigned a single virtual node.

REQUIRED. Name of the cookie.

Path to set for the cookie.

REQUIRED. Lifetime of the cookie.

Number of errors before a host is ejected from the connection pool. Defaults to 5. When the upstream host is accessed over HTTP, a 502, 503 or 504 return code qualifies as an error. When the upstream host is accessed over an opaque TCP connection, connect timeouts and connection error/failure events qualify as an error.

Time interval between ejection sweep analysis. format: 1h/1m/1s/1ms. MUST BE >=1ms. Default is 10s.

Minimum ejection duration. A host will remain ejected for a period equal to the product of minimum ejection duration and the number of times the host has been ejected. This technique allows the system to automatically increase the ejection period for unhealthy upstream servers. format: 1h/1m/1s/1ms. MUST BE >=1ms. Default is 30s.

Maximum % of hosts in the load balancing pool for the upstream service that can be ejected. Defaults to 10%.

Outlier detection will be enabled as long as the associated load balancing pool has at least minhealthpercent hosts in healthy mode. When the percentage of healthy hosts in the load balancing pool drops below this threshold, outlier detection will be disabled and the proxy will load balance across all hosts in the pool (healthy and unhealthy). The threshold can be disabled by setting it to 0%. The default is 0% as it’s not typically applicable in k8s environments with few pods per service.

REQUIRED. Name of the subset. The service name and the subset name can be used for traffic splitting in a route rule.

Labels apply a filter over the endpoints of a service in the service registry. See route rules for examples of usage.

Traffic policies that apply to this subset. Subsets inherit the traffic policies specified at the DestinationRule level. Settings specified at the subset level will override the corresponding settings specified at the DestinationRule level.

REQUIRED: Indicates whether connections to this port should be secured using TLS. The value of this field determines how TLS is enforced.

REQUIRED if mode is MUTUAL. The path to the file holding the client-side TLS certificate to use. Should be empty if mode is ISTIO_MUTUAL.

REQUIRED if mode is MUTUAL. The path to the file holding the client’s private key. Should be empty if mode is ISTIO_MUTUAL.

OPTIONAL: The path to the file containing certificate authority certificates to use in verifying a presented server certificate. If omitted, the proxy will not verify the server’s certificate. Should be empty if mode is ISTIO_MUTUAL.

A list of alternate names to verify the subject identity in the certificate. If specified, the proxy will verify that the server certificate’s subject alt name matches one of the specified values. If specified, this list overrides the value of subjectaltnames from the ServiceEntry.

SNI string to present to the server during TLS handshake.

Settings controlling the load balancer algorithms.

Settings controlling the volume of connections to an upstream service

Settings controlling eviction of unhealthy hosts from the load balancing pool

TLS related settings for connections to the upstream service.

Traffic policies specific to individual ports. Note that port level settings will override the destination-level settings. Traffic settings specified at the destination-level will not be inherited when overridden by port-level settings, i.e. default values will be applied to fields omitted in port-level traffic policies.

Specifies the number of a port on the destination service on which this policy is being applied.

Settings controlling the load balancer algorithms.

Settings controlling the volume of connections to an upstream service

Settings controlling eviction of unhealthy hosts from the load balancing pool

TLS related settings for connections to the upstream service.