Traffic Ops - Configuring¶
Follow the steps below to configure the newly installed Traffic Ops Instance.
Installing the SSL Certificate¶
By default, Traffic Ops runs as an SSL web server (that is, over HTTPS), and a certificate needs to be installed.
Self-signed Certificate (Development)¶
$ openssl genrsa -des3 -passout pass:x -out localhost.pass.key 2048 Generating RSA private key, 2048 bit long modulus ... $ openssl rsa -passin pass:x -in localhost.pass.key -out localhost.key writing RSA key $ rm localhost.pass.key $ openssl req -new -key localhost.key -out localhost.csr You are about to be asked to enter information that will be incorporated into your certificate request. What you are about to enter is what is called a Distinguished Name or a DN. There are quite a few fields but you can leave some blank For some fields there will be a default value, If you enter '.', the field will be left blank. ----- Country Name (2 letter code) [XX]:US<enter> State or Province Name (full name) :CO<enter> Locality Name (eg, city) [Default City]:Denver<enter> Organization Name (eg, company) [Default Company Ltd]: <enter> Organizational Unit Name (eg, section) : <enter> Common Name (eg, your name or your server's hostname) : <enter> Email Address : <enter> Please enter the following 'extra' attributes to be sent with your certificate request A challenge password : pass<enter> An optional company name : <enter> $ openssl x509 -req -sha256 -days 365 -in localhost.csr -signkey localhost.key -out localhost.crt Signature ok subject=/C=US/ST=CO/L=Denver/O=Default Company Ltd Getting Private key $ sudo cp localhost.crt /etc/pki/tls/certs $ sudo cp localhost.key /etc/pki/tls/private $ sudo chown trafops:trafops /etc/pki/tls/certs/localhost.crt $ sudo chown trafops:trafops /etc/pki/tls/private/localhost.key
Content Delivery Networks¶
Many of the settings for the different servers in a Traffic Control CDN are controlled by parameters in the Configure -> Parameters view of Traffic Portal. Parameters are grouped in profiles and profiles are assigned to a server or a Delivery Service. For a typical cache there are hundreds of configuration settings to apply. The Traffic Portal ‘Parameters’ view contains the defined settings. To make life easier, Traffic Portal allows for duplication, comparison, import and export of profiles. Traffic Ops also has a “Global profile” - the parameters in this profile are going to be applied to all servers in the Traffic Ops instance, or apply to Traffic Ops themselves. These parameters are:
|tm.url||global||The URL where this Traffic Ops instance is being served from.|
|tm.rev_proxy.url||global||Not required. The URL where the Traffic Ops Configuration file cache instance is being served from. Requires Traffic Ops ORT 2.1 and above. When configured, ORT will request configuration files via this FQDN, which should be setup as a reverse proxy to the Traffic Ops host or hosts. Suggested cache lifetime for these files is ~3 minutes or less. This setting allows for greater scalability of a CDN maintained by Traffic Ops by caching configuration files of profile and CDN scope.|
|tm.toolname||global||The name of the Traffic Ops tool. Usually “Traffic Ops”. Used in the About screen and in the comments headers of the files generated.|
|tm.infourl||global||This is the “for more information go here” URL, which is visible in the About page.|
|tm.logourl||global||This is the URL of the logo for Traffic Ops and can be relative if the logo is under
|tm.instance_name||global||The name of the Traffic Ops instance. Can be used when multiple instances are active. Visible in the About page.|
|tm.traffic_mon_fwd_proxy||global||When collecting stats from Traffic Monitor, Traffic Ops uses this forward proxy to pull the stats through. This can be any of the MID tier caches, or a forward cache specifically deployed for this purpose. Setting this variable can significantly lighten the load on the Traffic Monitor system and it is recommended to set this parameter on a production system.|
|geolocation.polling.url||CRConfig.json||The location of a GeoIP2 database for Traffic Router to use.|
|geolocation6.polling.url||CRConfig.json||The location of an IPv6 GeoIP2 database for Traffic Router to use when routing IPv6 traffic.|
|maxmind.default.override||CRConfig.json||The destination geographic coordinates to use for client location when the GeoIP2 database returns a default location that matches
the country code. This parameter can be specified multiple times with different values to support default overrides for multiple
countries. The reason for the name ‘MaxMind’ is because that is the default GeoIP2 implementation used by Comcast production servers.
These parameters should be set to reflect the local environment.
After running the
postinstall script, Traffic Ops has the following profiles pre-loaded:
|EDGE1||The profile to be applied to the latest supported version of ATS, when running as an EDGE cache|
|TR1||The profile to be applied to the latest version of Traffic Router|
|TM1||The profile to be applied to the latest version of Traffic Monitor|
|MID1||The profile to be applied to the latest supported version of ATS, when running as an MID cache|
|RIAK_ALL||Riak profile for all CDNs to be applied to the Traffic Vault servers|
The Traffic Server profiles contain some information that is specific to the hardware being used (most notably the disk configuration), so some parameters will have to be changed to reflect your configuration. Future releases of Traffic Control will separate the hardware and software profiles so it is easier to “mix-and-match” different hardware configurations.
Below is a list of cache parameters that are likely to need changes from the default profiles shipped with Traffic Ops:
|allow_ip||astats.config||This is a comma separated list of IPv4 Classless Inter-Domain Routing (CIDR) blocks that will have access to the ‘astats’ statistics on the caches. The Traffic Monitor IP addresses have to be included in this, if they are using IPv4 to monitor the caches.|
|allow_ip6||astats.config||This is a comma-separated list of IPv6 CIDR blocks that will have access to the ‘astats’ statistics on the caches. The Traffic Monitor IP addresses have to be included in this, if they are using IPv6 to monitor the caches.|
|Drive_Prefix||storage.config||The device path start of the disks. For example, if you have
|Drive_Letters||storage.config||The letter part of the disks, in the same example as above set this to
|purge_allow_ip||ip_allow.config||The IP address range that is allowed to execute the PURGE method on the caches (not related to Invalidate Content)|
|coalesce_masklen_v4||ip_allow.config||The mask length to use when coalescing IPv4 networks into one line using the NetAddr::IP Perl library.|
|coalesce_number_v4||ip_allow.config||The number to use when coalescing IPv4 networks into one line using the NetAddr::IP Perl library.|
|coalesce_masklen_v6||ip_allow.config||The mask length to use when coalescing IPv6 networks into one line using the NetAddr::IP Perl library.|
|health.threshold.loadavg||rascal.properties||The Unix ‘load average’ (see
|health.threshold.\ availableBandwidthInKbps||rascal.properties||The amount of bandwidth (in kilobits per second) that Traffic Router will try to keep available on the cache. For example: “”>1500000” means stop sending new traffic to this cache when traffic is at 8.5Gbps on a 10Gbps interface.|
Below is a list of Traffic Server plug-ins that need to be configured in the parameter table:
|astats_over_http||package||The package version for the
|trafficserver||package||The package version for the
|regex_revalidate||plugin.config||The configuration to be used for
|remap_stats||plugin.config||The configuration to be used for
Below is a list of cache parameters for special configuration, which are unlikely to need changes, but may be useful in particular circumstances:
|not_a_parent||parent.config||This is a boolean flag and is considered ‘true’ if it exists and has any value except ‘false’.
This prevents servers with this parameter in their profile from being inserted into the
Regions, Locations and Cache Groups¶
All servers have to have a ‘location’, which is their physical location. Each location is part of a ‘region’, and each region is part of a ‘division’. For Example,
Denver could be a location in the
Mile High region and that region could be part of the
West division. The hierarchy between these terms is illustrated graphically below.
To create these structures in Traffic Portal, first in enter your divisions under Topology->Divisions, then enter the regions in Topology->Regions, referencing the divisions entered and, finally, enter the physical locations in Topology->Phys Locations, referencing the regions entered.
All servers also have to be part of a Cache Group. A Cache Group is a logical grouping of caches, that don’t have to be in the same physical location (in fact, usually a cache group is spread across minimally 2 physical Locations for redundancy purposes), but share geographical coordinates for content routing purposes.
Configuring Content Purge¶
Content purge using ATS is not simple; there is no file system to delete files/directories from, and in large caches it can be hard to delete a simple regular expression from the cache. This is why Traffic Control uses the Regex Revalidate Plugin to purge content from the system. We don’t actually remove the content, we have a check that gets run before each request on each cache to see if this request matches a list of regular expressions, and if it does, we force a revalidation to the origin, making the original content inaccessible. The regex_revalidate plugin will monitor it’s config file, and will pick up changes to it without a traffic_line -x signal to ATS. Changes to this file need to be distributed to the highest tier (MID) caches in the CDN before they are distributed to the lower tiers, to prevent filling the lower tiers with the content that should be purged from the higher tiers without hitting the origin. This is why the ort script (see Configuring Traffic Server) will by default push out config changes to MID first, confirm that they have all been updated, and then push out the changes to the lower tiers. In large CDNs, this can make the distribution and time to activation of the purge too long, and because of that there is the option to not distribute the regex_revalidate.config file using the ort script, but to do this using other means. By default, Traffic Ops will use ort to distribute the regex_revalidate.config file.
Content Purge is controlled by the following parameters in the profile of the cache:
|location||regex_revalidate.config||Where in the file system file should located on the cache server.||The presence of this parameter tells ORT to distribute this file; delete this parameter from the profile if this file is distributed using other means.|
|maxRevalDurationDays||regex_revalidate.config||The maximum duration for which a purge shall be active.||To prevent a build up of many checks before each request, this is longest duration (in days) for which the system will allow content purges to remain active.|
|regex_revalidate||plugin.config||The configuration to be used for
|use_reval_pending||global||Configures Traffic Ops to use a separate
||When this flag is in use ORT will check for a new
Note that the TTL the adminstrator enters in the purge request should be longer than the TTL of the content to ensure the bad content will not be used. If the CDN is serving content of unknown, or unlimited TTL, the administrator should consider using proxy-config-http-cache-guaranteed-min-lifetime to limit the maximum time an object can be in the cache before it is considered stale, and set that to the same value as maxRevalDurationDays (Note that the former is in seconds and the latter is in days, so convert appropriately).
Creating the CentOS Kickstart File¶
The kickstart file is a text file, containing a list of items, each identified by a keyword. You can create it by using the Kickstart Configurator application, or writing it from scratch. The Red Hat Enterprise Linux installation program also creates a sample kickstart file based on the options that you selected during installation. It is written to the file
/root/anaconda-ks.cfg. This file is editable using most text editors that can save files as ASCII text.
To generate ISO, the CentOS Kickstart is necessary:
- Create a kickstart file.
- Create a boot media with the kickstart file or make the kickstart file available on the network.
- Make the installation tree available.
- Start the kickstart installation.
Create a ks.src file in the root of the selection location. See the example below:
mkdir newdir cd newdir/ cp -r ../centos65/* . vim ks.src vim isolinux/isolinux.cfg cd vim osversions.cfg vim osversions.cfg
This is a standard kickstart formatted file that the generate ISO process uses to create the kickstart (ks.cfg) file for the install. The generate ISO process uses the ks.src, overwriting any information set in the Generate ISO tab in Traffic Ops, creating ks.cfg.
Streamline your install folder for under 1GB, which assists in creating a CD.
For in-depth instructions, please see Kickstart Installation
Configuring the Go Application¶
Traffic Ops is in the process of migrating from Perl to Go, and currently runs as two applications. The Go application serves all endpoints which have been rewritten in the Go language, and transparently proxies all other requests to the old Perl application. Both applications are installed by the RPM, and both run as a single service. When the project has fully migrated to Go, the Perl application will be removed, and the RPM and service will consist solely of the Go application.
By default, the postinstall script configures the Go application to behave and transparently serve as the old Perl Traffic Ops did in previous versions. This includes reading the old
database.conf config files, and logging to the old
access.log location. However, if you wish to customize the Go Traffic Ops application, you can do so by running it with the
-oldcfg=false argument. By default, it will then look for a config file in
/opt/traffic_ops/conf/traffic_ops_golang.config. The new config file location may also be customized via the
-cfg flag. A sample config file is installed by the RPM at
/opt/traffic_ops/conf/traffic_ops_golang.config. If you wish to run the new Go Traffic Ops application as a service with a new config file, the
-cfg flags may be added to the
start function in the service file, located by default at