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Frequently Asked Questions

Welcome to the Apache Traffic Server FAQ.
Below is a list of frequently asked questions pertaining to Apache Traffic Server.

  1. What Platforms does Traffic Server support
  2. 'sudo make install' fails with '/usr/bin/install: invalid group nobody'
  3. How do I enable forward proxy mode?
  4. How do I access POST data in a Traffic Server plugin
  5. How do I enable DNS lookups?
  6. How do I enable SSL between Client/ATS/Origin end points?
  7. What happens if Traffic Server crashes?
  8. Do you have any sample configuration files?
  9. How do I profile Traffic Server's performance?
  10. How do get detailed logs for particular requests served by Traffic Server?
  11. How to enable cache inspector and others in http_ui?
  12. How do I setup a RAW disk cache?
  13. How do I know what debug tags are available?
  14. More questions?

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platforms
platforms

What Platforms does Traffic Server support
  • Linux is the primary platform supported.
  • For other distributions such as FreeBSD, Mac OSX and OpenSolaris see README

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nobody
nobody

'sudo make install' fails with '/usr/bin/install: invalid group nobody'
  • The default installed user is 'nobody' and the default group is 'nobody'.
  • You can specify the installed group via:
Code Block
titleshell
borderStylesolid
# It is very important to do a clean uninstall and distclean before
# re-configuring, re-building, and re-installing after the failed
# first install.
sudo make uninstall
sudo make distclean
configure i.e './configure --with-group=nogroup'

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forwardproxy
forwardproxy

How do I enable forward proxy mode?
  • Forward proxy mode is not enabled out of the box for security reasons. When enabling any proxy on the internet, you want to make sure you observe pertinent security restrictions. Having an open proxy available to internet users is a bad thing. If you understand this and are sure you know what you are doing, go ahead and enable:
    Code Block
    titletrafficserver/records.config
    borderStylesolid
        # Set this variable to 1 if you want Traffic Server to serve 
        # requests only from origin servers listed in the mapping rules
        # of the remap.config file. If a request does not match, then 
        # the browser will receive an error.
        CONFIG proxy.config.reverse_proxy.enabled INT 0
        CONFIG proxy.config.url_remap.remap_required INT 0
    

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postplugin
postplugin

How do I access POST data in a Traffic Server plugin

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dns
dns

How do I enable DNS lookups?
  • Edit records.config and enable round_robin along with specifying your nameservers. For example:
    Code Block
    titletrafficserver/records.config
    borderStylesolid
        # Enables (1) or disables (0) DNS server round-robin.
        CONFIG proxy.config.dns.round_robin_nameservers INT 1
    
        #The DNS servers.
        CONFIG proxy.config.dns.nameservers STRING 10.0.0.1 192.172.0.4
    

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ssl
ssl

How do I enable SSL between Client/ATS/Origin end points?

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crash
crash

What happens if Traffic Server crashes?
  • it is automatically restarted by the Traffic Manager
  • if you turn off cores (limit coredumpsize 0) you can prevent disk full errors on crash loops

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sample-configs
sample-configs

Do you have any sample configuration files?

Yes we do, see the sample configuration page.

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oprofile
oprofile

How do i profile Traffic Server's performance

Visit the Profiling page for more information.

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slowlog
slowlog

How do get detailed logs for particular requests served by Traffic Server?

You can set
CONFIG proxy.config.http.slow.log.threshold INT
in records.config to see various time milestones for HTTP requests in the error log. The value is in milliseconds, requests that take longer than that value will generate a slow log entry.

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http_ui
http_ui

How to enable cache inspector and others in http_ui?

http_ui is a cache inspector for TS internal system, a Swiss knife tool for TS, you can setup http_ui by:

  1. add these remap rules to remap.config, you may need to replace localhost to your own hostname if you don't access from localhost, you may need to modify the default port 8080 if you have changed it
    Code Block
    titleremap.config
    borderStylesolid
        map http://localhost:8080/cache-internal/ http://{cache-internal}
        map http://localhost:8080/cache/ http://{cache}
        map http://localhost:8080/stat/ http://{stat}
        map http://localhost:8080/test/ http://{test}
        map http://localhost:8080/hostdb/ http://{hostdb}
        map http://localhost:8080/net/ http://{net}
        map http://localhost:8080/http/ http://{http}
    
  2. enable http_ui from records.config, we use command line tool here:
    Code Block
    titlecommand
    borderStylesolid
        traffic_line -s proxy.config.http_ui_enabled -v 3
        traffic_line -s proxy.config.http.enable_http_info -v 1
    
  3. get traffic_server aware of the change:
    Code Block
    titlecommand
    borderStylesolid
        traffic_line -x
    
  4. testing with nc:
    Code Block
    titlecommand
    borderStylesolid
        echo -ne "GET http://localhost/stat/ HTTP/1.0\r\n\r\n" | nc -i 1 localhost 8080
    

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raw-disk
raw-disk

How do I setup a RAW disk cache?

RAW disk cache is specified in storage.config using the physical /dev device with no additional parameters provided you run a recent kernel.

Code Block
titlestorage.config
borderStylesolid
    /dev/dm-2

You must also ensure the trafficserver user owns the device and has block-level access. To do this we utilize udev rules. This must be a physical device and not an LVM mapping:

Code Block
title50-ats.rules
borderStylesolid
    # /etc/udev/rules.d/50-ats.rules
    # Apache Traffic Server owns disk for RAW access
    KERNEL=="dm-2", OWNER="trafficserver"

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debugtags
debugtags

How do I know what debug tags are available?

When enabling debug logging, you specify tags to filter the debug output with the proxy.config.diags.debug.tags option. The following command will show you all debug tags used in the trafficserver source code when outputting debug messages. Run it from inside the trafficserver source tree:

Code Block
# This assumes gnu grep
grep -orh 'Debug("[^"]*' * | sort | uniq | sed 's/Debug("//'

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more
more

More Frequently Asked Questions?