Traffic Router Administration
Requirements
CentOS 7 or later
4 CPUs
8GB of RAM
Successful install of Traffic Ops (usually on another machine)
Successful install of Traffic Monitor (usually on another machine)
Administrative access to Traffic Ops
Note
Hardware requirements are generally doubled if DNSSEC is enabled
Installing Traffic Router
If no suitable Profile exists, create a new Profile for Traffic Router via the + button on the Profiles page in Traffic Portal
Enter the Traffic Router server into Traffic Portal on the Servers page (or via the Traffic Ops API), assign to it a Traffic Router Profile, and ensure that its status is set to
ONLINE
.Ensure the FQDN of the Traffic Router is resolvable in DNS. This FQDN must be resolvable by the clients expected to use this CDN.
Install a Traffic Router server package, either from source or using a
traffic_router-version string.rpm
package generated using the instructions in Building Traffic Control.Changed in version 3.0: As of version 3.0, Traffic Router depends upon a package called
tomcat
. This package should have been created when Traffic Router was built. If installing thetraffic_router
produces a depenedency error, make sure that thetomcat
package is available in an accessible yum(8) repository.Edit
/opt/traffic_router/conf/traffic_monitor.properties
and specify the correct online Traffic Monitor(s) for your CDN.traffic_monitor.properties
URL that should normally point to this file, e.g.
traffic_monitor.properties=file:/opt/traffic_router/conf/traffic_monitor.properties
traffic_monitor.properties.reload.period
Period to wait (in milliseconds) between reloading this file, e.g.
traffic_monitor.properties.reload.period=60000
Start Traffic Router. This is normally done by starting its systemd(1) service.
systemctl start traffic_router
, and test DNS lookups against that server to be sure it’s resolving properly. with e.g.dig
orcurl
. Also, because previously taken CDN Snapshots will be cached, they need to be removed manually to actually be reloaded. This file should be located at/opt/traffic_router/db/cr-config.json
. This should be done before starting or restarting Traffic Router.[root@trafficrouter /]# systemctl start traffic_router [root@trafficrouter /]# dig @localhost mycdn.ciab.test ; <<>> DiG 9.9.4-RedHat-9.9.4-72.el7 <<>> @localhost mycdn.ciab.test ; (2 servers found) ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 27109 ;; flags: qr aa rd; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0 ;; WARNING: recursion requested but not available ;; QUESTION SECTION: ;mycdn.ciab.test. IN A ;; AUTHORITY SECTION: mycdn.ciab.test. 30 IN SOA trafficrouter.infra.ciab.test. twelve_monkeys.mycdn.ciab.test. 2019010918 28800 7200 604800 30 ;; Query time: 28 msec ;; SERVER: ::1#53(::1) ;; WHEN: Wed Jan 09 21:27:57 UTC 2019 ;; MSG SIZE rcvd: 104
Perform a CDN Snapshot.
Note
Once the Snapshot is taken, live traffic will be sent to the new Traffic Routers provided that their status has been set to
ONLINE
.Ensure that the parent domain (e.g.:
cdn.local
) for the CDN’s top level domain (e.g.:ciab.cdn.local
) contains a delegation (Name Server records) for the new Traffic Router, and that the value specified matches the FQDN of the Traffic Router.
Configuring Traffic Router
Changed in version 1.5: Many of the configuration files under /opt/traffic_router/conf
are now only needed to override the default configuration values for Traffic Router. Most of the given default values will work well for any CDN. Critical values that must be changed are hostnames and credentials for communicating with other Traffic Control components such as Traffic Ops and Traffic Monitor. Pre-existing installations that store configuration files under /opt/traffic_router/conf
will still be used and honored for Traffic Router 1.5 onward.
Changed in version 3.0: Traffic Router 3.0 has been converted to a formal Tomcat instance, meaning that is now installed separately from the Tomcat servlet engine. The Traffic Router installation package contains all of the Traffic Router-specific software, configuration and startup scripts including some additional configuration files needed for Tomcat. These new configuration files can all be found in the /opt/traffic_router/conf
directory and generally serve to override Tomcat’s default settings.
For the most part, the configuration files and Parameters used by Traffic Router are used to bring it online and start communicating with various Traffic Control components. Once Traffic Router is successfully communicating with Traffic Control, configuration should mostly be performed in Traffic Portal, and will be distributed throughout Traffic Control via CDN Snapshot process.
Configuration File |
Parameter Name |
Description |
Default Value |
---|---|---|---|
traffic_monitor.properties |
traffic_monitor.bootstrap.hosts |
Semicolon-delimited Traffic Monitor FQDNs with port numbers as necessary |
N/A |
traffic_monitor.bootstrap.local |
Use only the Traffic Monitors specified in local configuration files |
|
|
traffic_monitor.properties |
Path to file:traffic_monitor.properties; used internally to monitor the file for changes |
|
|
traffic_monitor.properties.reload.period |
The interval in milliseconds for Traffic Router to wait between reloading this configuration file |
|
|
dns.properties |
dns.tcp.port |
TCP port that Traffic Router will use for incoming DNS requests |
|
dns.tcp.backlog |
Maximum length of the queue for incoming TCP connection requests |
|
|
dns.tcp.host |
IP Address Traffic Router will listen on for incoming TCP DNS requests |
|
|
dns.udp.host |
IP Address Traffic Router will listen on for incoming UDP DNS requests |
|
|
dns.udp.port |
UDP port that Traffic Router will use for incoming DNS requests |
|
|
dns.max-threads |
Maximum number of threads used to process incoming DNS requests |
|
|
dns.queue-depth |
Maximum number of threads allowed to queue when all workers threads are busy. To disable the queue, set to 0, or to allow an unlimited sized queue, set to -1. |
|
|
dns.zones.dir |
Path to automatically generated zone files for reference |
|
|
dns.negative.caching.ttl |
Value (in seconds) to set as the |
|
|
traffic_ops.properties |
traffic_ops.username |
Username with which to access the Traffic Ops API
(must have the |
|
traffic_ops.password |
Password for the user specified in |
N/A |
|
cache.properties |
cache.geolocation.database |
Full path to the local copy of a geographic IP mapping database (usually MaxMind’s GeoIP2) |
|
cache.geolocation.database.refresh.period |
The interval in milliseconds for Traffic Router to wait between polling for changes to the GeoIP2 database |
|
|
cache.czmap.database |
Full path to the local copy of the coverage zone file |
|
|
cache.czmap.database.refresh.period |
The interval in milliseconds for Traffic Router to wait between polling for a new coverage zone file |
|
|
cache.dczmap.database |
Full path to the local copy of the deep coverage zone file |
|
|
cache.dczmap.database.refresh.period |
The interval in milliseconds for Traffic Router to wait between polling for a new deep coverage zone file |
|
|
cache.health.json |
Full path to the local copy of the health state |
|
|
cache.health.json.refresh.period |
The interval in milliseconds which Traffic Router will poll for a new health state file |
|
|
cache.config.json |
Full path to the locally cached copy of the CDN Snapshot |
|
|
cache.config.json.refresh.period |
The interval in milliseconds which Traffic Router will poll for a new Snapshot |
|
|
startup.properties |
various parameters |
This configuration is used by systemd(1) to set environment variables
when the |
N/A |
log4j2.xml |
various parameters |
Configuration of |
N/A |
server.xml |
various parameters |
Traffic Router specific configuration for Apache Tomcat. See the Apache Tomcat documentation |
N/A |
web.xml |
various parameters |
Default settings for all Web Applications running in the Traffic Router instance of Tomcat |
N/A |
The Traffic Router Profile
Much of a Traffic Router’s configuration can be obtained through the Parameters on its Profile. The Parameters of a Traffic Router’s Profile that have meaning (others are just ignored) are detailed in the The Parameters of a Traffic Router Profile.
Value Description |
||
---|---|---|
ecsEnable |
CRConfig.json |
Boolean value to enable or disable EDNS0 client subnet extensions. This is a universal value for the CDN but can be set on the Delivery Service level through the EDNS0 Client Subnet Enabled field. |
geolocation.polling.url |
CRConfig.json |
The location (URL) where a geographic IP mapping database may be found. |
geolocation.polling.interval |
CRConfig.json |
How often - in milliseconds - Traffic Router should check for an updated geographic IP mapping database. |
certificates.polling.interval |
CRConfig.json |
How often - in milliseconds - Traffic Router should check for Delivery Service certificates. |
certificate.api.url |
CRConfig.json |
The location (URL) where Traffic Router can request Delivery Service certificates from. |
regional_geoblock.polling.interval |
CRConfig.json |
How often - in milliseconds - Traffic Router should check for Regional Geo-blocking rules. |
regional_geoblock.polling.url |
CRConfig.json |
The location (URL) where Traffic Router can request Regional Geo-blocking rules from. |
anonymousip.policy.configuration |
CRConfig.json |
The location (URL) where Traffic Router can request the Anonymous IP Blocking configuration file from. |
anonymousip.polling.url |
CRConfig.json |
The location (URL) where Traffic Router can request the Anonymous IP Database from. |
anonymousip.polling.interval |
CRConfig.json |
How often - in milliseconds - Traffic Router should check for the Anonymous IP Blocking configuration and database |
coveragezone.polling.interval |
CRConfig.json |
How often - in milliseconds - Traffic Router should check for an updated Coverage Zone Map. |
coveragezone.polling.url |
CRConfig.json |
The location (URL) where a Coverage Zone Map may be found. |
deepcoveragezone.polling.interval |
CRConfig.json |
How often - in milliseconds - Traffic Router should check for an updated Deep Coverage Zone Map |
deepcoveragezone.polling.url |
CRConfig.json |
The location (URL) where a Deep Coverage Zone Map may be found. |
strip.special.query.params |
CRConfig.json |
If “true”, Traffic Router will strip its special query parameters (namely “trred” and “fakeClientIpAddress”) from its responses. Note: the special query parameter “format” is not stripped due to its generality. |
tld.soa.expire |
CRConfig.json |
The value for the “expire” field the Traffic Router DNS Server will respond with on SOA records. |
tld.soa.minimum |
CRConfig.json |
The value for the minimum field the Traffic Router DNS Server will respond with on SOA records. |
tld.soa.admin |
CRConfig.json |
The DNS Start of Authority administration email address, which clients will be directed to contact for support if DNS is not working correctly. |
tld.soa.retry |
CRConfig.json |
The value for the “retry” field the Traffic Router DNS Server will respond with on SOA records. |
tld.soa.refresh |
CRConfig.json |
The value for the “refresh” field the Traffic Router DNS Server will respond with on SOA records. |
tld.ttls.NS |
CRConfig.json |
The TTL the Traffic Router DNS Server will respond with on NS records. |
tld.ttls.SOA |
CRConfig.json |
The TTL the Traffic Router DNS Server will respond with on SOA records. |
tld.ttls.AAAA |
CRConfig.json |
The TTL the Traffic Router DNS Server will respond with on AAAA records. |
tld.ttls.A |
CRConfig.json |
The TTL the Traffic Router DNS Server will respond with on A records. |
tld.ttls.DNSKEY |
CRConfig.json |
The TTL the Traffic Router DNS Server will respond with on DNSKEY records. |
tld.ttls.DS |
CRConfig.json |
The TTL the Traffic Router DNS Server will respond with on DS records. |
api.port |
server.xml |
The TCP port on which Traffic Router servers the Traffic Router API. |
api.cache-control.max-age |
CRConfig.json |
The value of the |
api.auth.url |
CRConfig.json |
The URL of the authentication endpoint of the Traffic Ops API (user/login). The actual
FQDN can be subsituted with |
consistent.dns.routing |
CRConfig.json |
Control whether DNS-routed Delivery Services use Consistent Hashing. May improve performance if set to “true”; defaults to “false”. |
dnssec.enabled |
CRConfig.json |
Whether DNSSEC is enabled; this parameter is updated via the DNSSEC administration user interface in Traffic Portal. |
dnssec.allow.expired.keys |
CRConfig.json |
Allow Traffic Router to use expired DNSSEC keys to sign zones; default is “true”. This helps prevent DNSSEC related outages due to failed Traffic Control components or connectivity issues. |
dynamic.cache.primer.enabled |
CRConfig.json |
Allow Traffic Router to attempt to prime the dynamic zone cache; defaults to “true”. |
dynamic.cache.primer.limit |
CRConfig.json |
Limit the number of permutations to prime when dynamic zone cache priming is enabled; defaults to “500”. |
edge.dns.limit |
CRConfig.json |
Integer that controls the default number of records returned when edge.dns.routing is set to true |
edge.dns.routing |
CRConfig.json |
Boolean flag to control whether edge routing is enabled; this controls localization of NS records |
edge.http.limit |
CRConfig.json |
Integer that controls the default number of records returned when edge.http.routing is set to true; this can be overridden by the maxDnsAnswers delivery service setting |
edge.http.routing |
CRConfig.json |
Boolean flag to control whether edge routing is enabled; this controls localization of traffic router routing names for HTTP delivery service records |
keystore.maintenance.interval |
CRConfig.json |
The interval in seconds which Traffic Router will check the Traffic Ops API for new DNSSEC keys. |
keystore.api.url |
CRConfig.json |
The URL of the DNSSEC key management endpoint of the Traffic Ops API (cdns/name/{{name}}/dnsseckeys). The actual
FQDN may be substituted with |
keystore.fetch.timeout |
CRConfig.json |
The timeout in milliseconds for requests to the DNSSEC Key management endpoint of the Traffic Ops API (cdns/name/{{name}}/dnsseckeys). |
keystore.fetch.retries |
CRConfig.json |
The number of times Traffic Router will attempt to load DNSSEC keys before giving up; defaults to “5”. |
keystore.fetch.wait |
CRConfig.json |
The number of milliseconds Traffic Router will wait in between attempts to load DNSSEC keys |
signaturemanager.expiration.multiplier |
CRConfig.json |
Multiplier used in conjunction with a zone’s maximum TTL to calculate DNSSEC signature durations; defaults to “5”. |
zonemanager.threadpool.scale |
CRConfig.json |
Multiplier used to determine the number of CPU cores to use for zone signing operations; defaults to “0.75”. |
zonemanager.cache.maintenance.interval |
CRConfig.json |
The interval in seconds on which Traffic Router will check for zones that need to be re-signed or if dynamic zones need to be expired from its cache. |
zonemanager.dynamic.response.expiration |
CRConfig.json |
A duration (e.g.: “300s”) that defines how long a dynamic zone will remain valid before expiring. |
zonemanager.dynamic.concurrencylevel |
CRConfig.json |
An integer that defines the size of the concurrency level (threads) of the Guava cache used by ZoneManager to store zone material. |
zonemanager.dynamic.initialcapacity |
CRConfig.json |
An integer that defines the initial size of the Guava cache, default is 10000. Too low of a value can lead to expensive resizing. |
zonemanager.init.timeout |
CRConfig.json |
An integer that defines the number of minutes to allow for zone generation; this bounds the zone priming activity. |
DNSKEY.generation.multiplier |
CRConfig.json |
Used to determine when new DNSSEC keys need to be generated. Keys are re-generated if expiration is less than the generation multiplier multiplied by the TTL. If this Parameter does not exist, the default is “10”. |
DNSKEY.effective.multiplier |
CRConfig.json |
Used when creating an effective date for a new key set. New keys are generated with an effective date of that is the effective multiplier multiplied by the TTL less than the old key’s expiration date. Default is “2”. |
Deprecated since version ATCv4.0: The use of “CRConfig.xml” as a Parameter “Config File” value has no known meaning, and its use for configuring Traffic Router is deprecated. All configuration (?) that previously used that value should instead use the equivalent Parameter with the Config File value “CRConfig.json”.
Consistent Hashing
Traffic Router does special optimization for some requests to ensure that requests for specific content are consistently fetched from a small number (often exactly one, but dependent on Initial Dispersion) of cache servers - thus ensuring it stays “fresh” in the cache. This is done by performing “consistent hashing” on request paths (when HTTP routing) or names requested for resolution (when DNS routing). To an extent, this behavior is configurable by modifying fields on Delivery Services. Consistent hashing acts differently on a Delivery Service based on how Delivery Services of its Type route content.
- HTTP, HTTP_NO_CACHE, HTTP_LIVE, HTTP_LIVE_NATNL, DNS, DNS_LIVE, and DNS_NATNL
These Delivery Service Types route directly to cache servers, so consistent hashing is used to choose a cache server to which the client will be redirected.
- STEERING and CLIENT_STEERING
These Delivery Service Types route to “target” Delivery Services, so consistent hashing is used to choose a “target” which will service the client request.
See also
Consistent Hashing Patterns
New in version 4.0.
Regular expressions (“patterns”) can be provided in the Consistent Hashing Regular Expression field of an HTTP-routed Delivery Service to influence what parts of an HTTP request path are considered when performing consistent hashing. These patterns propagate to Traffic Router through Snapshots.
Important
Consistent Hashing Patterns on STEERING-Type Delivery Services will be used for Consistent Hashing - the Consistent Hashing Pattern(s) of said Delivery Service’s target(s) will not be considered. If Consistent Hashing Patterns are important to the routing of content on a STEERING-Type or CLIENT_STEERING-Type Delivery Service, they must be defined on that Delivery Service itself, and not on its target(s).
How it Works
The supplied Consistent Hashing Regular Expression is applied to the request path to extract matching elements to build a new string before consistent hashing is done. For example, using the pattern /.*?(/.*?/).*?(m3u8)
and given the request paths /test/path/asset.m3u8
and /other/path/asset.m3u8
the resulting string used for consistent hashing will be /path/m3u8
See also
See Oracle’s documentation for the java.util.regex.Pattern implementation in Java.
Testing Pattern-Based Consistent Hashing
In order to test this feature without affecting the delivery of traffic through a CDN, there are several test tools in place.
- Traffic Router API
Several Traffic Router endpoints exist to test regular expression application against a request path, cache server selection, and Delivery Service selection.
- Traffic Ops API
The consistenthash endpoint will proxy request data through to one of the Traffic Router endpoints in order to test regular expression application against a request path, in the event that direct access to the Traffic Router API is not possible and/or desired.
- Traffic Portal
On the Delivery Service creation/modification form in Traffic Portal (under Delivery Services), there is a Test Regex section that the user can use to validate a regular expression before saving it to a Delivery Service.
Consistent Hash Query Parameters
Normally, when performing consistent hashing for an HTTP-routed Delivery Service, any query parameters present in the request are ignored. That is, if a client requests /some/path?key=value
consistent hashing is only performed on the string ‘/some/path
’. However, query parameters that are part of uniquely identifying content can be specified by adding them to the set of Consistent Hashing Query Parameters of a Delivery Service. For example, suppose that the file /video.mp4
is available on the origin server in different resolutions, which are specified by the resolution
query parameter. This means that /video.mp4?resolution=480p
and /video.mp4?resolution=720p
share a request path, but represent different content. In that case, adding resolution
to the Delivery Service’s Consistent Hashing Query Parameters will cause consistent hashing to be done on e.g. /video.mp4?resolution=480p
instead of just /video.mp4
- however if the client requests e.g. /video.mp4?resolution=480p&bitrate=120kbps
consistent hashing will only consider /video.mp4?resolution=480p
.
Note
Consistent Hashing Patterns are applied before query parameters are considered - i.e. a pattern cannot match against query parameters, and need not worry about query parameters contaminating matches.
Important
Consistent Hash Query Parameters on the targets of STEERING-Type Delivery Services will be used for Consistent Hashing - the Consistent Hash Query Parameters of said Delivery Services themselves will not be considered. If Consistent Hash Query Parameters are important to the routing of content on a STEERING-Type or CLIENT_STEERING-Type Delivery Service, they must be defined on that Delivery Service’s’ target(s), and not on the Delivery Service itself.
Caution
Certain query parameters are reserved by Traffic Router for its own use, and thus cannot be present in any Consistent Hash Query Parameters. These reserved parameters are:
trred
format
fakeClientIPAddress
DNSSEC
Overview
DNSSEC is a set of extensions to DNS that provides a cryptographic mechanism for resolvers to verify the authenticity of responses served by an authoritative DNS server. Several RFCs (RFC 4033, RFC 4044, RFC 4045) describe the low level details and define the extensions, RFC 7129 provides clarification around authenticated denial of existence of records, and finally RFC 6781 describes operational best practices for administering an authoritative DNSSEC-enabled DNS server. The authenticated denial of existence RFC 7129 describes how an authoritative DNS server responds in NXDOMAIN and NODATA scenarios when DNSSEC is enabled. Traffic Router currently supports DNSSEC with NSEC, however, NSEC3 and more configurable options are planned for the future.
Operation
Upon startup or a configuration change, Traffic Router obtains keys from the ‘keystore’ API in Traffic Ops which returns KSKs and ZSKs for each Delivery Service that is a sub-domain of the CDN’s TLD in addition to the keys for the CDN TLD itself. Each key has timing information that allows Traffic Router to determine key validity (expiration, inception, and effective dates) in addition to the appropriate TTL to use for the DNSKEY record(s). All TTLs are configurable Parameters in The Traffic Router Profile.
Once Traffic Router obtains the key data from the API, it converts each public key into the appropriate record types (DNSKEY, DS) to place in zones and uses the private key to sign zones. DNSKEY records are added to each Delivery Service’s zone (e.g.: demo1.mycdn.ciab.test
) for every valid key that exists, in addition to the CDN TLD’s zone. A DS record is generated from each zone’s KSK and is placed in the CDN TLD’s zone (e.g.: mycdn.ciab.test
); the DS record for the CDN TLD must be placed in its parent zone, which is not managed by Traffic Control.
The DNSKEY to DS record relationship allows resolvers to validate signatures across zone delegation points. With Traffic Control, we control all delegation points below the CDN’s TLD, however, the DS record for the CDN TLD must be placed in the parent zone (e.g.: ciab.test
), which is not managed by Traffic Control. As such, the DS record must be placed in the parent zone prior to enabling DNSSEC, and prior to generating a new CDN KSK. Based on your deployment’s DNS configuration, this might be a manual process or it might be automated. Either way, extreme care and diligence must be taken and knowledge of the management of the upstream zone is imperative for a successful DNSSEC deployment.
To enable DNSSEC for a CDN in Traffic Portal, Go to CDNs from the sidebar and click on the desired CDN, then toggle the ‘DNSSEC Enabled’ field to ‘true’, and click on the green Update button to save the changes.
Rolling Zone Signing Keys
Traffic Router currently follows the ZSK pre-publishing operational best practice described in RFC 6781#section-4.1.1.1. Once DNSSEC is enabled for a CDN in Traffic Portal, key rolls are triggered by Traffic Ops via the automated key generation process, and Traffic Router selects the active ZSKs based on the expiration information returned from the ‘keystore’ API of Traffic Ops.
Edge Traffic Routing
Overview
Edge Traffic Routing is a feature that enables localization for more DNS record types than just the routing name for DNS delivery services. This feature has two main components: localization of HTTP delivery service routing names and localization for CDN-managed NS records. This allows Traffic Router to scale horizontally more easily, as there is a practical limit to how many records can be in an RRset for NS
, A
, or AAAA
record types. The practical limit is typically an answer size exceeding 512 bytes; we have observed issues where some clients and/or resolvers do not honor larger answer responses, while in some cases, resolvers are unable to use TCP for larger responses. Additionally, this feature allows Traffic Router to serve an RRset containing only Traffic Routers that are near the client (resolver), placing more control over which Traffic Routers a given resolver or client will interact with.
Localizing NS
records reduces latency for the resolver, which, due to caching in DNS is of little utility for NS
records, but it will force resolvers to use the closest Traffic Routers for all queries. This is important for look-ups of CDN routing name records that have very short TTLs, meaning DNS traffic for routing name records is frequent. Like localization for routing names of DNS delivery services, localizing the routing name for HTTP delivery services provides the client (end user) with a list of Traffic Routers that are physically close, reducing latency when the client moves from DNS resolution to the HTTP connection to Traffic Router for the 302 redirect to the edge cache. This feature reduces latency between a resolver and Traffic Router, reduces latency for the client’s HTTP request to Traffic Router, and allows Traffic Control to dictate which Traffic Routers are used in any given location when a client can be localized.
Edge DNS Routing
Edge DNS routing refers to the localization of NS
records in Traffic Router. This can be turned on and off via the edge.dns.routing
parameter; the number of records returned is controlled via edge.dns.limit
and there is a hard-coded default limit of 4 when this feature is enabled. See The Traffic Router Profile documentation for parameter details.
Edge HTTP Routing
Edge HTTP routing refers to the localization of A
and AAAA
records that represent routing names for HTTP delivery services. This can be turned on and off via the edge.http.routing
parameter; the number of records returned is controlled via edge.http.limit
and there is a hard-coded default limit of 4 when this feature is enabled. The default or global limit can be overridden by modifying the maxDnsAnswers
setting on the delivery service. See The Traffic Router Profile documentation for parameter details.
Edge Traffic Router Selection
Traffic Router performs localization on client requests in order to determine which Traffic Routers should service a given request. After localization, Traffic Router will perform a consistent hash on the incoming name and will use the value to refine Traffic Router selection. There are two main cases for Traffic Router selection: a localization hit, and a localization miss.
Localization Hit: Consistent Hash (CH)
When a client is localized, Traffic Router selects the nearest Traffic Router Location (Cache Group) based on proximity. Proximity is determined by using the latitude and longitude of the client, regardless of whether it is a coverage zone or geolocation hit, and the latitude and longitude specified on Traffic Router Locations. Once the location is identified, a consistent hash is performed on the incoming name and the list of Traffic Routers is ordered based upon the consistent hash. Once ordered, the list is limited to the appropriate number based on the limit parameter specified by the hard-coded default (4), edge.dns.limit
, edge.http.limit
, or maxDnsAnswers
, depending on the configuration and request being localized. This approach can be thought of as the CH selection process.
Localization Miss: Consistent Hash + Round Robin (CH + RR)
When a client cannot be localized, Traffic Router still needs to produce a list of Traffic Routers to service the request. Because the number of Traffic Routers in the CDN could far exceed the practical limits of what constitutes a “normal” sized answer, a selection algorithm is applied to select Traffic Routers. Much like the localization hit scenario, the incoming request name is consistent hashed and results size is limited by the same parameters. Because no client location is known, Traffic Router must distribute the load across all Traffic Router Locations. To distribute the load, Traffic Router will order all Traffic Routers at each location based on the consistent hash, selecting a Traffic Router at the nth position, incrementing the index, n, after iterating over all locations.
For example, with four Traffic Router Locations each containing 10 Traffic Routers and a limit of 6, the algorithm would:
Consistent hash the incoming name
Order the Traffic Routers at each location by the consistent hash
Select the Traffic Router at at the first position of each location
Select the Traffic Router at the second position of each location, stopping after selecting the 6th Traffic Router
Because the algorithm employs consistent hashing, the answers should be consistent as long as the topology remains the same. This approach can be thought of as the consistent hash round robin (CH + RR) selection process.
Example Request Flow
The following is an example of the request flow when a client requests the routing name for an example delivery service, tr.service.cdn.example.com
. The request flow assumes that the resolver is cold and has yet to build a local cache of look-ups, meaning it has to walk the domain hierarchy asking for NS
records until it reaches service.cdn.example.com
. This example starts after the resolver has determined which name servers are authoritative for cdn.example.com
. Note that the same logic is applied for each of the three queries made by the resolver.

Fig. 21 Example Request Flow for Edge Traffic Routing. Note this picks up when the resolver hits the CDN managed domain.
Troubleshooting and log files
Traffic Router log files can be found under /opt/traffic_router/var/log
and /opt/tomcat/logs
. Initialization and shutdown logs are in /opt/tomcat/logs/catalinadate.out
. Application related logging is in /opt/traffic_router/var/log/traffic_router.log
, while access logs are written to /opt/traffic_router/var/log/access.log
.
Event Log File Format
Summary
All access events to Traffic Router are logged to the file /opt/traffic_router/var/log/access.log
. This file grows up to 200MB and gets rolled into older log files, ten log files total are kept (total of up to 2GB of logged events per Traffic Router instance)
Traffic Router logs access events in a format that largely follows ATS event logging format.
Message Format
Except for the first item, each event that is logged is a series of space-separated key/value pairs.
The first item is always the Unix epoch in seconds with a decimal field precision of up to milliseconds.
Each key/value pair is in the form of
unquoted_string="optionally quoted string"
Values that are quoted strings may contain whitespace characters.
Values that are not quoted should not contains any whitespace characters.
Note
Any value that is a single dash character or a dash character enclosed in quotes represents an empty value
Name |
Description |
Data |
---|---|---|
qtype |
Whether the request was for DNS or HTTP |
Always “DNS” or “HTTP” |
chi |
The IP address of the requester |
Depends on whether this was a DNS or HTTP request, see other sections |
rhi |
The IP address of the request source address |
Depends on whether this was a DNS or HTTP request, see other sections |
ttms |
The amount of time in milliseconds it took Traffic Router to process the request |
A number greater than or equal to zero |
rtype |
Routing result type |
One of ERROR, CZ, DEEP_CZ, GEO, MISS, STATIC_ROUTE, DS_REDIRECT, DS_MISS, INIT, FED |
rloc |
GeoLocation of result |
Latitude and longitude in degrees as floating point numbers |
rdtl |
Result details Associated with unusual conditions |
One of DS_NOT_FOUND, DS_NO_BYPASS, DS_BYPASS, DS_CZ_ONLY, DS_CZ_BACKUP_CG |
rerr |
Message about an internal Traffic Router error |
String |
See also
If Regional Geo-Blocking is enabled on the Delivery Service, an additional field (rgb
) will appear.
Sample Message
Items within brackets are detailed under the HTTP and DNS sections
144140678.000 qtype=DNS chi=192.168.10.11 rhi=- ttms=789 [Fields Specific to the DNS request] rtype=CZ rloc="40.252611,58.439389" rdtl=- rerr="-" [Fields Specific to the DNS result]
144140678.000 qtype=HTTP chi=192.168.10.11 rhi=- ttms=789 [Fields Specific to the HTTP request] rtype=GEO rloc="40.252611,58.439389" rdtl=- rerr="-" [Fields Specific to the HTTP result]
Note
These samples contain fields that are always present for every single access event to Traffic Router
rtype
Meanings
-
The request was not redirected. This is usually a result of a DNS request to the Traffic Router or an explicit denial for that request
- ANON_BLOCK
The client’s IP matched an Anonymous Blocking rule and was blocked
- CZ
The result was derived from Coverage Zone data based on the address in the
chi
field- DEEP_CZ
The result was derived from Deep Coverage Zone data based on the address in the
chi
field- DS_MISS
_*HTTP Only*_ No HTTP Delivery Service supports either this request’s URL path or headers
- DS_REDIRECT
The result is using the Bypass Destination configured for the matched Delivery Service when that Delivery Service is unavailable or does not have the requested resource
- ERROR
An internal error occurred within Traffic Router, more details may be found in the
rerr
field- FED
_*DNS Only*_ The result was obtained through federated coverage zone data outside of any Delivery Services
- GEO
The result was derived from geolocation service based on the address in the
chi
field- GEO_REDIRECT
The request was redirected based on the National Geo blocking (Geo Limit Redirect URL) configured on the Delivery Service
- GEO_DS
The request was redirected to the Miss Location configured on the Delivery Service, because CZF couldn’t resolve the client IP, and Maxmind returned the default coordinates of the country code of the client IP
- MISS
Traffic Router was unable to resolve a DNS request or find a cache for the requested resource
- RGALT
The request was redirected to the Regional Geo-Blocking URL. Regional Geo blocking is enabled on the Delivery Service and is configured through the
regional_geoblock.polling.url
Parameter on the Traffic Router Profile- RGDENY
_*DNS Only*_ The result was obtained through federated coverage zone data outside of any Delivery Service - the request was regionally blocked because there was no rule for the request made
- STATIC_ROUTE
_*DNS Only*_ No DNS Delivery Service supports the hostname portion of the requested URL
rdtl
Meanings
-
The request was not redirected. This is usually a result of a DNS request to the Traffic Router or an explicit denial for that request
- DS_BYPASS
Used a bypass destination for redirection of the Delivery Service
- DS_CLIENT_GEO_UNSUPPORTED
Traffic Router did not find a resource supported by coverage zone data and was unable to determine the geographic location of the requesting client
- DS_CZ_BACKUP_CG
Traffic Router found a backup cache via fall-back (through the
edgeLocation
field of a Snapshot) or via coordinates (Coverage Zone File) configuration- DS_CZ_ONLY
The selected Delivery Service only supports resource lookup based on coverage zone data
- DS_NO_BYPASS
No valid bypass destination is configured for the matched Delivery Service and the Delivery Service does not have the requested resource
- DS_NOT_FOUND
Always goes with
rtypes
STATIC_ROUTE and DS_MISS- GEO_NO_CACHE_FOUND
Traffic Router could not find a resource via geographic location data based on the requesting client’s location
- NO_DETAILS
This entry is for a standard request
- REGIONAL_GEO_ALTERNATE_WITHOUT_CACHE
This goes with the
rtype
RGDENY. The URL is being regionally blocked- REGIONAL_GEO_NO_RULE
The request was blocked because there was no rule in the Delivery Service for the request
HTTP Specifics
1452197640.936 qtype=HTTP chi=69.241.53.218 rhi=- url="http://foo.test.example.com/some/asset.m3u8" cqhm=GET cqhv=HTTP/1.1 rtype=GEO rloc="40.252611,58.439389" rdtl=- rerr="-" pssc=302 ttms=0 rurl="http://cache1.test.example.com:8090/some/asset.m3u8" rh="Accept: */*" rh="myheader: asdasdasdasfasg"
Name |
Description |
Data |
|
---|---|---|---|
url |
Requested URL with query string |
A URL String |
|
cqhm |
Http Method |
e.g |
|
cqhv |
Http Protocol Version |
e.g. |
|
rh |
One or more of these key value pairs may exist in a logged event and are controlled by the configuration of the matched Delivery Service | Key/value pair of the format |
Name |
Description |
---|---|
rurl |
The resulting URL of the resource requested by the client |
DNS Specifics
144140678.000 qtype=DNS chi=192.168.10.11 rhi=- ttms=123 xn=65535 fqdn=www.example.com. type=A class=IN ttl=12345 rcode=NOERROR rtype=CZ rloc="40.252611,58.439389" rdtl=- rerr="-" ans="192.168.1.2 192.168.3.4 0:0:0:0:0:ffff:c0a8:102 0:0:0:0:0:ffff:c0a8:304"
Name |
Description |
Data |
---|---|---|
xn |
The ID from the client DNS request header |
a whole number between 0 and 65535 (inclusive) |
rhi |
The IP address of the resolver when EDNS0 client subnet extensions are enabled. |
An IPv4 or IPv6 string, or dash if request is for resolver only and no client subnet is present |
fqdn |
The qname field from the client DNS request message (i.e. the FQDN the client is requesting be |
A series of DNS labels/domains separated by ‘.’ characters and ending with a ‘.’ character |
type |
The qtype field from the client DNS request message (i.e. the typeof resolution that’s requested such as IPv4, IPv6) |
Examples are A (IpV4), AAAA (IpV6), NS, SOA, and CNAME, (see qtype) |
class |
The qclass field from the client DNS request message (i.e. the class of resource being requested) |
Either IN or ANY (Traffic Router rejects requests with any other value of class) |
Name |
Description |
Data |
---|---|---|
ttl |
The ‘time to live’ in seconds for the answer provided by Traffic Router (clients can reliably use this answer for this long without re-querying traffic router) |
A whole number between 0 and 4294967295 (inclusive) |
rcode |
The result code for the DNS answer provided by Traffic Router |
One of NOERROR (success), NOTIMP (request is not NOTIMP (request is not supported), REFUSED (request is refused to be answered), or NXDOMAIN (the domain/name requested does not exist) |
Deep Caching
Overview
Deep Caching is a feature that enables clients to be routed to the closest possible “deep” Edge-tier cache servers on a per-Delivery Service basis. The term “deep” is used in the networking sense, meaning that the Edge-tier cache servers are located deep in the network where the number of network hops to a client is as minimal. This deep caching topology is desirable because storing content closer to the client gives better bandwidth savings, and sometimes the cost of bandwidth usage in the network outweighs the cost of adding storage. While it may not be feasible to cache an entire copy of the CDN’s contents in every deep location (for the best possible bandwidth savings), storing just a relatively small amount of the CDN’s most requested content can lead to very high bandwidth savings.
What You Need
Edge cache deployed in “deep” locations and registered in Traffic Ops
A Deep Coverage Zone File mapping these deep cache hostnames to specific network prefixes
Deep caching Parameters in the Traffic Router Profile
deepcoveragezone.polling.interval
deepcoveragezone.polling.url
See also
See The Traffic Router Profile for details.
Deep Caching enabled on one or more HTTP Delivery Services (i.e. ‘Deep Caching’ field on the Delivery Service details page (under Advanced Options) set to
ALWAYS
)
How it Works
Deep Coverage Zone routing is very similar to that of regular Coverage Zone routing, except that the DCZF is preferred over the regular CZF for Delivery Services with Deep Caching enabled. If the client requests a Deep Caching-enabled Delivery Service and their IP address gets a “hit” in the DCZF, Traffic Router will attempt to route that client to one of the available “deep” cache servers in the client’s corresponding zone. If there are no “deep” cache servers available for a client’s request, Traffic Router will fall back to the regular CZF and continue regular CZF routing from there.
Steering Feature
Overview
A Steering Delivery Service is a Delivery Service that is used to route a client to another Delivery Service. The Type of a Steering Delivery Service is either STEERING or CLIENT_STEERING. A Steering Delivery Service will have target Delivery Services configured for it with weights assigned to them. Traffic Router uses the weights to make a consistent hash ring which it then uses to make sure that requests are routed to a target based on the configured weights. This consistent hash ring is separate from the consistent hash ring used in cache selection.
Special regular expressions - referred to as ‘filters’ - can also be configured for target Delivery Services to pin traffic to a specific Delivery Service. For example, if the filter .*/news/.*
for a target called target-ds-1
is created, any requests to Traffic Router with “news” in them will be routed to target-ds-1
. This will happen regardless of the configured weights.
Some other points of interest
Steering is currently only available for HTTP Delivery Services that are a part of the same CDN.
A new role called STEERING has been added to the Traffic Ops database. Only users with the Steering Role or higher can modify steering assignments for a Delivery Service.
Traffic Router uses the steering endpoints of the Traffic Ops API to poll for steering assignments, the assignments are then used when routing traffic.
A couple simple use-cases for Steering are:
Migrating traffic from one Delivery Service to another over time.
Trying out new functionality for a subset of traffic with an experimental Delivery Service.
Load balancing between Delivery Services
The Difference Between STEERING and CLIENT_STEERING
The only difference between the STEERING and CLIENT_STEERING Delivery Service Types is that CLIENT_STEERING explicitly allows a client to bypass Steering by choosing a destination Delivery Service. A client can accomplish this by providing the X-TC-Steering-Option
HTTP header with a value of the xml_id
of the target Delivery Service to which they desire to be routed. When Traffic Router receives this header it will route to the requested target Delivery Service regardless of weight configuration. This header is ignored by STEERING Delivery Services.
Configuration
The following needs to be completed for Steering to work correctly:
Two target Delivery Services are created in Traffic Ops. They must both be HTTP Delivery Services part of the same CDN.
A Delivery Service with type STEERING or CLIENT_STEERING is created in Traffic Portal.
Target Delivery Services are assigned to the Steering Delivery Service using Traffic Portal.
A user with the role of Steering is created.
The Steering user assigns weights to the target Delivery Services.
If desired, the Steering user can create filters for the target Delivery Services.
See also
For more information see Configure Delivery Service Steering.
HTTPS for HTTP Delivery Services
New in version 1.7: Traffic Router now has the ability to allow HTTPS traffic between itself and clients on a per-HTTP Delivery Service basis.
Note
As of version 3.0 Traffic Router has been integrated with native OpenSSL. This makes establishing HTTPS connections to Traffic Router much less expensive than previous versions. However establishing an HTTPS connection is more computationally demanding than an HTTP connection. Since each client will in turn get redirected to an ATS instance, Traffic Router is most always creating a new HTTPS connection for all HTTPS traffic. It is likely to mean that an existing Traffic Router may have some decrease in performance if you wish to support a lot of HTTPS traffic. As noted for DNSSEC, you may need to plan to scale Traffic Router vertically and/or horizontally to handle the new load.
The HTTPS set up process is:
Select one of ‘1 - HTTPS’, ‘2 - HTTP AND HTTPS’, or ‘3 - HTTP TO HTTPS’ for the Delivery Service
Generate private keys for the Delivery Service using a wildcard domain such as
*.my-delivery-service.my-cdn.example.com
Obtain and import signed certificate chain
Perform a CDN Snapshot
Clients may make HTTPS requests to Delivery Services only after the CDN Snapshot propagates to Traffic Router and it receives the certificate chain from Traffic Ops.
Protocol Options
- HTTP
Any secure client will get an SSL handshake error. Non-secure clients will experience the same behavior as prior to 1.7
- HTTPS
Traffic Router will only redirect (send a
302 Found
response) to clients communicating with a secure connection, all other clients will receive a503 Service Unavailable
response- HTTP AND HTTPS
Traffic Router will redirect both secure and non-secure clients
- HTTP TO HTTPS
Traffic Router will redirect non-secure clients with a
302 Found
response and a location that is secure (i.e. anhttps://
URL instead of anhttp://
URL), while secure clients will be redirected immediately to an appropriate target or cache server.
Certificate Retrieval
Warning
If you have HTTPS Delivery Services in your CDN, Traffic Router will not accept any connections until it is able to fetch certificates from Traffic Ops and load them into memory. Traffic Router does not persist certificates to the Java Keystore or anywhere else.
Traffic Router fetches certificates into memory:
At startup time
When it receives a new CDN Snapshot
Once an hour starting whenever the most recent of the last of the above occurred
Note
To adjust the frequency at which Traffic Router fetches certificates add the Parameter certificates.polling.interval
with the ConfigFile “CRConfig.json” and set it to the desired duration in milliseconds.
Note
Taking a CDN Snapshot may be used at times to avoid waiting the entire polling cycle for a new set of certificates.
Warning
If a CDN Snapshot is taken that involves a Delivery Service missing its certificates, Traffic Router will ignore ALL changes in that CDN Snapshot until one of the following occurs:
It receives certificates for that Delivery Service
Another CDN Snapshot is taken and the Delivery Service without certificates is changed such that its HTTP protocol is set to ‘http’
Certificate Chain Ordering
The ordering of certificates within the certificate bundle matters. It must be:
Primary Certificate (e.g. the one created for
*.my-delivery-service.my-cdn.example.com
)Intermediate Certificate(s)
Root Certificate from a CA (optional)
Warning
If something is wrong with the certificate chain (e.g. the order of the certificates is backwards or for the wrong domain) the client will get an SSL handshake. Inspection of /opt/tomcat/logs/catalina.log
is likely to yield information to reveal this.
To see the ordering of certificates you may have to manually split up your certificate chain and use openssl(1ssl) on each individual certificate
Automatic Certificate Management Environment
Automatic Certificate Management Environment (ACME) is a protocol for automatically generating, renewing, and revoking SSL certificates. Currently, ACME can be used through Let’s Encrypt or through External Account Binding.
External Account Binding
External account binding allows the user to use an existing account with an ACME provider to obtain, renew, and revoke SSL certificates. To use this functionality, fill in the fields in cdn.conf for the ACME provider with which the account is set up. The first time this is used for a specific ACME provider (defined by the acme_provider and user_email fields) the information will be used to get a private key and account URL from the ACME provider and register the account. These will be stored for later use. External account binding information can only be used once, so after the first time, the private key and URL will be used.
Important
The acme_provider and user_email combination must be unique. The acme_provider field must correlate to the AuthType field for each certificate to be renewed using that provider.
External account binding can be set up through cdn.conf by updating the following fields:
Name |
Type |
Required |
Description |
---|---|---|---|
acme_provider |
string |
Yes |
The certificate provider. This field needs to correlate to the AuthType field for each certificate so the renewal functionality knows which provider to use. |
user_email |
string |
Yes |
The email used to set up the account with the provider. |
acme_url |
string |
Yes |
The URL for the ACME. |
kid |
string |
No |
The key ID provided by the ACME provider for external account binding. |
hmac_encoded |
string |
No |
The HMAC key provided by the ACME provider for external account binding. This should be in Base64 URL encoded. |
Note
The kid and hmac_encoded fields are required unless the account has already been registered and the information has been stored in the Traffic Ops Database.
Let’s Encrypt
Let’s Encrypt is a free, automated CA using ACME protocol. Let’s Encrypt performs a domain validation before issuing or renewing a certificate. There are several options for domain validation but for this application the DNS challenge is used in order to receive wildcard certificates. Let’s Encrypt sends a token to be used as a TXT record at _acme-challenge.domain.example.com
and after verifying that the token is accessible there, will return the newly generated and signed certificate and key. The basic workflow implemented is:
POST
to Let’s Encrypt and receive the DNS challenge token.Traffic Ops stores the DNS challenge.
Traffic Router has a watcher which checks with Traffic Ops for any new challenges or deleted challenges.
When a new record appears, Traffic Router temporarily adds a static route for the specified Delivery Service with the token from Let’s Encrypt at
_acme-challenge.domain.example.com
.Let’s Encrypt continuously attempts to resolve it as a TXT record to verify ownership of the domain.
Note
DNSSec should be turned on for any CDN using Let’s Encrypt to guard against a ‘Man in the Middle’ interference with this transaction.
Let’s Encrypt returns the signed certificate and key to Traffic Ops.
Traffic Ops stores the certificate and key in Traffic Vault and removes the DNS challenge record.
The Traffic Router watcher removes the TXT record.
Let’s Encrypt can be set up through cdn.conf by updating the following fields:
Name |
Type |
Required |
Description |
---|---|---|---|
user_email |
string |
Yes |
Email to create account with Let’s Encrypt or to receive expiration updates. If this is not included then rate limits may apply for the number of certificates. |
send_expiration_email |
boolean |
No |
Option to send email summarizing certificate expiration status |
convert_self_signed |
boolean |
No |
Option to convert self signed to Let’s Encrypt certificates as they expire. Only works for certificates labeled as Self Signed in the Certificate Source field. |
renew_days_before_expiration |
int |
No |
Number of days before expiration date to renew certificates |
environment |
string |
No |
Let’s Encrypt environment to use. Options are ‘staging’ or ‘production’. Defaults to ‘production’. |
Automatic Certificate Renewal
If desired, an automated certificate renewal script is located at /traffic_ops/etc/cron.d/autorenew_certs
. This job is setup to be run, but the file must be updated with the username and password for Traffic Ops in order to be run. In cdn.conf the following fields can be defined in order to alter the number of days in advance to renew and send a summary email after renewal.
Note
In order for this to work, the AuthType field for the certificate must match the ACME provider in the cdn.conf.
Important
After the automatic renewal script has run, a queue and snapshot must be run manually in order for the certificates to be used.
Name |
Type |
Required |
Description |
---|---|---|---|
summary_email |
boolean |
No |
The email address to use for summarizing certificate expiration and renewal status. If it is blank, no email will be sent. |
renew_days_before_expiration |
int |
No |
Number of days before expiration date to renew certificates. Default is 30 days. |
Name |
Type |
Description |
---|---|---|
enabled |
boolean |
Enable sending emails through Simple Mail Transfer Protocol (SMTP) |
user |
string |
User for SMTP server access |
password |
string |
Password for SMTP server access |
address |
string |
SMTP server address including port |
Suggested Way of Setting up an HTTPS Delivery Service With Let’s Encrypt Automation
Assuming you have already created a Delivery Service which you plan to modify to use HTTPS, do the following in Traffic Portal:
Select one of ‘1 - HTTPS’, ‘2 - HTTP AND HTTPS’, or ‘3 - HTTP TO HTTPS’ for the protocol field of a Delivery Service and click the Update button
Go to
Click on
Click on the Use Let’s Encrypt slider, click on the green Generate Keys button, then confirm that you want to make these changes
Take a new CDN Snapshot
Once this is done you should be able to verify that you are being correctly redirected by Traffic Router using e.g. curl(1) commands to HTTPS destinations on your Delivery Service.
Router Load Testing
The Traffic Router load testing tool is located in the Traffic Control repository under test/router. It can be used to simulate a mix of HTTP and HTTPS traffic for a CDN by choosing the number of HTTP Delivery Services and the number HTTPS Delivery Service the test will exercise.
There are 2 parts to the load test:
A web server that makes the actual requests and takes commands to fetch data from the CDN, start the test, and return current results.
A web page that’s used to run the test and see the results.
Running the Load Tests
First, clone the Traffic Control repository.
You will need to make sure you have a CA file on your machine
The web server is a Go program, set your
GOPATH
environment variable appropriately (we suggest$HOME/go
or$HOME/src
)Open a terminal emulator and navigate to the
test/router/server
directory inside of the cloned repositoryExecute the server binary by running
go run server.go
Using your web browser of choice, open the file
test/router/index.html
Authenticate against a Traffic Ops host - this should be a nearly instantaneous operation - you can watch the output from
server.go
for feedbackEnter the Traffic Ops host in the second form and click the button to get a list of CDN’s
Wait for the web page to show a list of CDN’s under the above form, this may take several seconds
The List of CDN’s will display the number of HTTP- and HTTPS-capable Delivery Services that may be exercised
Choose the CDN you want to exercise from the drop-down menu
Fill out the rest of the form, enter appropriate numbers for each HTTP and HTTPS Delivery Services
Click Run Test
As the test runs the web page will occasionally report results including running time, latency, and throughput
Tuning Recommendations
The following is an example of the command line parameters set in /opt/traffic_router/conf/startup.properties
that has been tested on a multi-core server running under HTTPS load test requests. This is following the general recommendation to use the G1 garbage collector for JVM applications running on multi-core machines. In addition to using the G1 garbage collector the InitiatingHeapOccupancyPercent
was lowered to run garbage collection more frequently which improved overall throughput for Traffic Router and reduced ‘Stop the World’ garbage collection. Note that any environment variable settings in this file will override those set in /lib/systemd/system/traffic_router.service
.
CATALINA_OPTS="\
-server -Xms2g -Xmx8g \
-Dlog4j.configurationFile=$CATALINA_BASE/conf/log4j2.xml \
-Djava.library.path=/usr/lib64 \
-XX:+UseG1GC \
-XX:+UnlockExperimentalVMOptions \
-XX:InitiatingHeapOccupancyPercent=30"