The Akamai Connector for Varnish allows for the integration of data and configuration between an origin Varnish server and Akamai’s CDN network.
The latest version of the Akamai Connector is 1.0.7.
In order to install the Akamai Connector for Varnish, you first need to setup access to the connector repo. If you have not already done so, please contact support at support@varnish-software.com to get assistance with repo setup.
> apt-get install varnish-plus-akamai-connector
> yum install varnish-plus-akamai-connector
The following configuration steps are required to get the Akamai Connector running within your Varnish setup.
include "akamai_41_auto.vcl";
This will automatically hook Akamai request and response logic into the appropriate vcl_* subroutines. All Connector functionality is enabled and no further configuration is required.
Note: This examples assumes VCL version 4.1 (there is a vcl 4.1 line in your VCL configuration). If you are using VCL version 4.0 you need to include “akamai_auto.vcl” instead of “akamai_41_auto.vcl”.
If you would like to synchronize purge requests on this host
to the Akamai network, the following Akamai CCU API fields need
to be configured within the /etc/varnish/akamai-connector.conf file:
Omitting these fields or removing this configuration file will cause the Akamai purge functionality to be skipped entirely.
You can also point Varnish Cache to an alternate configuration path by setting VMOD_AKAMAI_CONFIG_FILE to the alternate path.
Example
export VMOD_AKAMAI_CONFIG_FILE=/opt/akamai/.ac.conf
Starting in version 1.0.7, the connector supports purge by cache tag and CP Code.
The Connector reads its settings from a configuration file, parsed at VCL
load time. By default this is /etc/varnish/akamai-connector.conf. If the
default file is missing, a warning is logged to syslog and the Connector
falls back to the built-in defaults.
An alternate path can be set with the VMOD_AKAMAI_CONFIG_FILE environment
variable. Note that VCL load fails if the file specified by this variable
cannot be opened, unlike a missing file at the default path.
The following example contains every available configuration key, with its default value:
# CCU (purge) API credentials, generated in the Luna Control Center.
# The purge functions are no-ops unless these are configured.
purge_access_token = ""
purge_client_token = ""
purge_client_secret = ""
purge_host = ""
purge_scheme = "https"
purge_network = "production"
# CCU v3 API endpoints. These rarely need to be changed.
purge_url = "/ccu/v3/invalidate/url"
purge_cachetag_url = "/ccu/v3/invalidate/tag"
purge_cpcode_url = "/ccu/v3/invalidate/cpcode"
delete_url = "/ccu/v3/delete/url"
delete_cachetag_url = "/ccu/v3/delete/tag"
delete_cpcode_url = "/ccu/v3/delete/cpcode"
# Size in bytes of the synthetic SureRoute test object (maximum 1GB).
sureroute_resp_bytes = "20480"
# Outbound proxy used for CCU API calls, specified as
# [scheme]://[user:secret]@host[:port]. Empty means no proxy.
proxy = ""
# Set to 1 to tunnel API calls through the proxy (HTTP CONNECT).
http_proxy_tunnel = "0"
To selectively choose which features of the Connector you wish to use,
you can use the following vcl subroutines (via akamai.vcl):
Each subroutines need to be called in the appropriate sub vcl_* subroutine as
specified in the 2nd part of the name. For example, akamai_deliver_edge_control
needs to be called in sub vcl_deliver. If multiple subroutines have the same
functionality label, as specified by the 3rd part of the name, each one needs
to be invoked. For example, both akamai_recv_esi and akamai_deliver_esi
need to be called to integrate ESI with Akamai.
Sureroute Example:
include "akamai.vcl";
sub vcl_init {
call akamai_init_sureroute;
}
sub vcl_recv {
call akamai_recv_sureroute;
}
If you have unused subroutines, you can disable Varnish Cache from reporting
them as an error by adding the following startup parameter to varnishd:
-p vcc_err_unref=false
Tag Based Purging:
This example will show how to override the akamai_auto.vcl to use a different
purging call to Akamai to purge by cache tags. Additionally, this will show you
how to use ykey purging at the same time as Akamai purging. Akamai assigns
cache tags to an object through the response header Edge-Cache-Tag
include "akamai_auto.vcl";
sub vcl_recv {
if (req.method == "PURGE") {
# Purge Varnish and Akamai with tags
set req.http.ykey_purges = ykey.purge(req.http.tags);
akamai.purge_cachetag(req.http.tags);
return (synth(941, "Purged"));
}
}
# Add information about ykey purge to synthetic return
sub vcl_synth {
if (resp.status == 941) {
set resp.http.ykey_purges = req.http.ykey_purges;
}
# Output from Akamai purge automatically added from
# akamai_auto.vcl
}
sub vcl_backend_response {
# Align ykey keys with Akamai cache tags
ykey.add_key(beresp.http.Edge-Cache-Tag);
}
In order to direct all request via a proxy on can set the “proxy”-key in the VMOD_AKAMAI_CONFIG_FILE. Set the key-value to a string specifing the proxy, like this [scheme]://[user:secret]@IP|host[:port]. See libcurl documentation for more details on defining a proxy.
Tunneling is also supported and enabled by setting the “http_proxy_tunnel”-key to 1 in the VMOD_AKAMAI_CONFIG_FILE.
The Akamai Connector requires no additional changes to your Akamai configuration and is designed to operate with your current Akamai environment as-is.
For best results, ensure that your Akamai configuration classifies requests as cacheable by default and excludes those requests that are not cacheable.
The Connector, using VCL, can correctly define the cacheability status and appropriate TTLs. However, the early classification will ensure that the Akamai Intelligent Platform will use SureRoute and Tiered Distribution for non cacheable and cacheable content respectfully.
To utilize Device Characteristics in Varnish you will need to enable the behavior for Device Characteristics on your Configuration.
Run the following curl command:
curl -I http://[host]/akamai/testobject.html \
-H "Via: akamai.net(ghost) (AkamaiGHost)"
Substitute [host] with the name or IP address of the Varnish server running the Akamai Connector.
You should see the following response:
HTTP/1.1 200 OK
Content-Length: 20480
Date: Thu, 09 Mar 2017 23:19:41 GMT
X-Varnish: 2
Edge-Control: max-age=130
Cache-Control: post-check=120
Via: 1.1 varnish-v4, Akamai Connector/[version]
X-varnish-hits: 0
Accept-Ranges: bytes
Connection: keep-alive
In particular, verify you have a successful 200 response code or that the Via header states Akamai Connector.
The Akamai Connector for Varnish offers the following functionality.
The Varnish Cache internal value of beresp.ttl, beresp.grace, and beresp.uncacheable will be synchronized with the Akamai CDN on each request. These values will supersede the Cache-Control header.
In your Luna Property Configuration for Akamai, set your caching behavior to honor origin cache control and expires.
When a purge request is handled by Varnish Cache, the Connector will synchronize the invalidation request against the Akamai CDN. The Connector will use the value of req.url and req.http.Host for invalidation.
The akamai-connector.conf needs to have all of the purge_* fields filled in, otherwise purge synchronization is skipped on this host.
If purge synchronization is configured, Varnish Cache will relay the Akamai CCU API response as its purge response.
CCU API credentials need to be generated via the Luna Control Center.
The Varnish Cache value of req.http.True-Client-IP will always contain the True Client IP of the requestor.
This is implemented by the shipped akamai_recv_true_client_ip
subroutine: if the incoming request has no True-Client-IP header, the
value is derived from the first element of X-Forwarded-For, or from
client.ip if that header is also absent.
Note that an incoming True-Client-IP header is trusted as-is; it is
neither stripped nor validated. This is fine when Varnish is only reachable
via Akamai, but if the listener can be reached directly, strip the header
at the edge to prevent clients from spoofing it.
In Luna, make sure the header used is True-Client-IP.
The shipped VCL identifies requests coming from Akamai by matching the
Via request header against akamai.net(ghost) (AkamaiGHost). The
Connector does not perform any inbound shared-secret validation, and since
the Via header can be spoofed, this check does not prove a request came
through Akamai if the listener is reachable directly.
If stronger identification is required, implement your own secret header check in VCL, for example by having Akamai send a custom header with a shared secret and rejecting requests that lack it.
The Connector will respond to SureRoute test object requests with a native
SureRoute response. The shipped akamai_recv_sureroute subroutine matches
both /akamai/testobject.html and /akamai/sureroute-test-object.html
and routes them to a synthetic backend, which fabricates a 200 response
without fetching from the origin.
The response size is configured via sureroute_resp_bytes in akamai-connector.conf.
In Luna, make sure the SureRoute test object path is /akamai/testobject.html
or /akamai/sureroute-test-object.html.
These test object paths are hardcoded in the shipped VCL. To use a custom
path, do not call akamai_recv_sureroute; instead create a sureroute
backend and route your own URL to it in vcl_recv:
sub vcl_init {
# Instantiate the backend yourself instead of calling
# akamai_init_sureroute
new sureroute = akamai.sureroute();
}
sub vcl_recv {
if (req.url == "/custom/testobject.html") {
set req.backend_hint = sureroute.backend();
# The built-in VCL turns a request carrying either of these into a
# pass, which would regenerate the test object on every request
unset req.http.cookie;
unset req.http.authorization;
return (hash);
}
}
This mirrors what akamai_recv_sureroute does. The two unset
statements and return (hash) matter: SureRoute measures the network
path rather than the origin, so the synthetic object should be served from
cache. Returning pass instead would work, but would rebuild the object
on every test request.
ESI processing in Varnish Cache is deferred to Akamai when requests originate from the Akamai CDN.
In Luna, make sure the ESI processor is enabled.
Each characteristic in the X-Akamai-Device-Characteristics field will be put into its own header. The header name is X-ADC-[characteristic] where [characteristic] is the characteristic name. For example, the value of is_mobile will be put into the X-ADC-is_mobile header.
Connections between Akamai CDN and Varnish Cache will be held open for 301 seconds.
The connector supports Akamai calls to purge by cache tag and CP Code.
These functions require the akamai-connector.conf to be configured with the
appropriate Akamai CCU API values for purge_host, purge_client_token,
purge_client_secret, and purge_access_token. The connector will automatically
sign the request using the configured Akamai credentials in akamai-connector.conf.
If akamai-connector.conf is not configured, these calls do nothing.
BOOL is_esi()
Returns true if the object to be delivered was scanned during fetch for ESI instructions (beresp.do_esi was set).
This is useful in situations where you have layered caches, and for some set of the incoming requests Varnish is not the edge layer where the ESI processing should be executed. To help the next layer know whether the data should be scanned for ESI instructions or not, this vmod can be used to set a response header.
This is deprecated by the equivalent obj.can_esi variable.
Arguments: None
Type: Function
Returns: Bool
Restricted to: vcl_deliver
VOID set_session_timeout_idle(DURATION timeout)
Set the session idle timeout. The timeout will be set for the current session only, and will silently fail if the session is not available in the current VCL sub.
Note: This function will only have effect if the target Varnish version has built in support for per session idle timeouts.
Example
sub vcl_recv {
if(...) {
akamai.set_session_timeout_idle(300s);
}
}
Arguments:
timeout accepts type DURATIONType: Function
Returns: None
REAL duration2real(DURATION, REAL)
Convert a VCL DURATION to a VCL REAL.
Arguments: None
Type: Function
Returns: Real
DURATION obj_ttl()
Return the obj.ttl. Only valid in VCL functions where obj exists. Returns 0 if called from any other VCL function.
Arguments: None
Type: Function
Returns: Duration
DURATION obj_grace()
Return the obj.grace. Only valid in VCL functions where obj exists. Returns 0 if called from any other VCL function.
Arguments: None
Type: Function
Returns: Duration
DURATION obj_keep()
Return the obj.keep. Only valid in VCL functions where obj exists. Returns 0 if called from any other VCL function.
Arguments: None
Type: Function
Returns: Duration
VOID parse_adc_params(STRING)
Parse the Akamai Device Characteristics header string. Each value gets put into its own request header with an X-ADC- prefix.
Expects the format to be param=value with semicolon separating pairs and optional spaces in between.
Example
sub vcl_recv {
akamai.akamai.parse_adc_params("brand_name=Google;is_tablet=false; device_os=Android");
if (req.http.X-ADC-brand_name == "Google") {
...
}
}
Arguments: None
Type: Function
Returns: None
VOID purge(STRING url, STRING hostname = "", BOOL delete = 0, STRING delims = "")
Send a purge request to the Akamai CCU API. This requires the akamai-connector.conf to be configured with the appropriate Akamai CCU API values for purge_host, purge_client_token, purge_client_secret, and purge_access_token. If the akamai-connector.conf is not configured, this call does nothing.
Arguments:
url accepts type STRING
hostname accepts type STRING with a default value of empty. optional
delete accepts type BOOL with a default value of 0 optional
delims accepts type STRING with a default value of empty. optional
Type: Function
Returns: None
VOID purge_cachetag(STRING tags, BOOL delete = 0, STRING delims = " ,")
Send a cache tag purge request to the Akamai CCU API. This requires the akamai-connector.conf to be configured with the appropriate Akamai CCU API values for purge_host, purge_client_token, purge_client_secret, and purge_access_token. If the akamai-connector.conf is not configured, this call does nothing.
Arguments:
tags accepts type STRING
delete accepts type BOOL with a default value of 0 optional
delims accepts type STRING with a default value of , optional
Type: Function
Returns: None
VOID purge_cpcode(STRING cpcodes, BOOL delete = 0, STRING delims = " ,")
Send a cpcode purge request to the Akamai CCU API. This requires the akamai-connector.conf to be configured with the appropriate Akamai CCU API values for purge_host, purge_client_token, purge_client_secret, and purge_access_token. If the akamai-connector.conf is not configured, this call does nothing.
Arguments:
cpcodes accepts type STRING
delete accepts type BOOL with a default value of 0 optional
delims accepts type STRING with a default value of , optional
Type: Function
Returns: None
VOID api(STRING method, STRING url, STRING json)
Send an Akamai CCU v3 API call.
Arguments:
method accepts type STRING
url accepts type STRING
json accepts type STRING
Type: Function
Returns: None
INT get_resp_code()
Get the response code for the last invocation of purge(). If purge() was
not called, 0 is returned.
Arguments: None
Type: Function
Returns: Int
STRING get_resp_body()
Get the response body for the last invocation of purge(). If purge() was
not called, an empty string is returned.
Arguments: None
Type: Function
Returns: String
STRING get_resp_reason()
Get the response reason phrase for the last invocation of purge(). If purge() was
not called, an empty string is returned.
Arguments: None
Type: Function
Returns: String
OBJECT sureroute()
Create a sureroute backend.
Arguments: None
Type: Object
Returns: Object.
BACKEND .backend()
Return the sureroute backend.
Arguments: None
Type: Method
Returns: Backend
STRING get_useragent()
Return the user agent string for this VMOD, a composition of the VMOD name and version.
Arguments: None
Type: Function
Returns: String
The akamai connector VMOD is available in Varnish Enterprise version 6.0.2r1 and later.