The parent.config file identifies the parent proxies used in an cache hierarchy. Use this file to perform the following configuration:

• Set up parent cache hierarchies, with multiple parents and parent failover
• Configure selected URL requests to bypass parent proxies

Traffic Server uses the parent.config file only when the parent caching option is enabled (refer to Configuring Traffic Server to Use a Parent Cache).

IMPORTANT: After you modify the parent.config file, navigate to the Traffic Serverbin directory and run the traffic_line -x command to apply your changes. When you apply the changes to one node in a cluster, Traffic Server automatically applies the changes to all other nodes in the cluster.

Format

Each line in the parent.config file must contain a parent caching rule. Traffic Server recognizes three space-delimited tags:

primary_destination=value secondary_specifie=value  action=value

The following list shows the possible primary destinations and their allowed values.

dest_domain

A requested domain name.

dest_host

A requested hostname.

dest_ip

A requested IP address or range of IP addresses separated by a dash (-).

url_regex

A regular expression (regex) to be found in a URL

The secondary specifiers are optional in the parent.config file. The following list shows the possible secondary specifiers and their allowed values.

port

A requested URL port.

scheme

A request URL protocol: http or https.

prefix

A prefix in the path part of a URL.

suffix

A file suffix in the URL.

method

A request URL method. It can be one of the following:

• get
• post
• put
• trace

time

A time range, such as 08:00-14:00, during which the parent cache is used to serve requests.

src_ip

A client IP address.

The following list shows the possible actions and their allowed values.

parent

An ordered list of parent servers. If the request cannot be handled by the last parent server in the list, then it will be routed to the origin server. You can specify either a hostname or an IP address, but; you must specify the port number.

round_robin

One of the following values:

• true - Traffic Server goes through the parent cache list in a round robin-based on client IP address.
• strict - Traffic Server machines serve requests strictly in turn. For example: machine proxy1 serves the first request, proxy2 serves the second request, and so on.
• false - Round robin selection does not occur.

go_direct

One of the following values:

• true - requests bypass parent hierarchies and go directly to the origin server.
• false - requests do not bypass parent hierarchies.

Examples

The following rule configures a parent cache hierarchy consisting of Traffic Server (which is the child) and two parents, p1.x.com and p2.x.com. Traffic Server forwards the requests it cannot serve to the parent servers p1.x.com and p2.x.com in a round-robin fashion because:

round_robin=true
dest_domain=. method=get parent="p1.x.com:8080; p2.y.com:8080" round_robin=true

The following rule configures Traffic Server to route all requests containing the regular expression politics and the path /viewpoint directly to the origin server (bypassing any parent hierarchies): url_regex=politics prefix=/viewpoint go_direct=true

Every line in the parent.config file must contain either a parent= or go_direct= directive.