.. _ref-varnishd:

=========
 varnishd
=========

-----------------------
HTTP accelerator daemon
-----------------------

:Author: Dag-Erling Smørgrav
:Author: Stig Sandbeck Mathisen
:Author: Per Buer
:Date:   2010-05-31
:Version: 1.0
:Manual section: 1


SYNOPSIS
========

varnishd [-a address[:port]] [-b host[:port]] [-d] [-F] [-f config] 
	 [-g group] [-h type[,options]] [-i identity]
	 [-l shmlogsize] [-n name] [-P file] [-p param=value] 
	 [-s type[,options]] [-T address[:port]] [-t ttl]
	 [-r param[,param...]] [-u user] [-V] 

DESCRIPTION
===========

The varnishd daemon accepts HTTP requests from clients, passes them on to a backend server and caches the
returned documents to better satisfy future requests for the same document.

.. _ref-varnishd-options:

OPTIONS
=======

-a address[:port][,address[:port][...]
	    Listen for client requests on the specified address and port.  The address can be a host
            name (“localhost”), an IPv4 dotted-quad (“127.0.0.1”), or an IPv6 address enclosed in
            square brackets (“[::1]”).  If address is not specified, varnishd will listen on all
            available IPv4 and IPv6 interfaces.  If port is not specified, the default HTTP port as
            listed in /etc/services is used.  Multiple listening addresses and ports can be speci‐
            fied as a whitespace- or comma-separated list.

-b host[:port]
            Use the specified host as backend server.  If port is not specified, 
	    the default is 8080.

-C	    Print VCL code compiled to C language and exit. Specify the VCL file 
	    to compile with the -f option.

-d          Enables debugging mode: The parent process runs in the foreground with a CLI connection
            on stdin/stdout, and the child process must be started explicitly with a CLI command.
            Terminating the parent process will also terminate the child.

-F          Run in the foreground.

-f config   Use the specified VCL configuration file instead of the
            builtin default.  See vcl(7) for details on VCL
            syntax. When no configuration is supplied varnishd will
            not start the cache process.

-g group    Specifies the name of an unprivileged group to which the child process should switch
            before it starts accepting connections.  This is a shortcut for specifying the group
            run-time parameter.

-h type[,options]
            Specifies the hash algorithm.  See Hash Algorithms for a list of supported algorithms.

-i identity
            Specify the identity of the varnish server.  This can be accessed using server.identity
            from VCL

-l shmlogsize
            Specify size of shmlog file.  Scaling suffixes like 'k', 'm' can be used up to
            (e)tabytes.  Default is 80 Megabytes.  Specifying less than 8 Megabytes is unwise.

-n name     Specify a name for this instance.  Amonst other things, this name is used to construct
            the name of the directory in which varnishd keeps temporary files and persistent state.
            If the specified name begins with a forward slash, it is interpreted as the absolute
            path to the directory which should be used for this purpose.

-P file     Write the process's PID to the specified file.

-p param=value
            Set the parameter specified by param to the specified value.  See Run-Time 
	    Parameters for a list of parameters. This option can be used multiple 
	    times to specify multiple parameters.

-S file     Path to a file containing a secret used for authorizing access to the management port.

-s [name=]type[,options]
            Use the specified storage backend. The storage backends can be one of the following:
               * malloc[,size]
               * file[,path[,size[,granularity]]]
               * persistent,path,size

            See Storage Types in the Users Guide for more information
            on the various storage backends.  This option can be used
            multiple times to specify multiple storage files. Names
            are referenced in logs, vcl, statistics, etc.

-T address[:port]
            Offer a management interface on the specified address and port.  See Management
            Interface for a list of management commands.

-M address:port
            Connect to this port and offer the command line
            interface. Think of it as a reverse shell. When running with 
	    -M and there is no backend defined the child process (the cache)
            will not start initially.

-t ttl      
	    Specifies a hard minimum time to live for cached
            documents.  This is a shortcut for specifying the
            default_ttl run-time parameter.

-r param[,param...]
            Make the listed parameters read only. This gives the
            system administrator a way to limit what the Varnish CLI can do.
            Consider making parameters such as *user*, *group*, *cc_command*,
            *vcc_allow_inline_c* read only as these can potentially be used
            to escalate privileges from the CLI.
            Protecting *listen_address* may also be a good idea.

-u user     Specifies the name of an unprivileged user to which the child
            process should switch before it starts accepting
            connections.  This is a shortcut for specifying the user
            run- time parameter.
	    
            If specifying both a user and a group, the user should be
            specified first.

-V          Display the version number and exit.


Hash Algorithms
---------------

The following hash algorithms are available:

simple_list
  A simple doubly-linked list.  Not recommended for production use.

classic[,buckets]
  A standard hash table.  This is the default.  The hash key is the
  CRC32 of the object's URL modulo the size of the hash table.  Each
  table entry points to a list of elements which share the same hash
  key. The buckets parameter specifies the number of entries in the
  hash table.  The default is 16383.

critbit
  A self-scaling tree structure. The default hash algorithm in 2.1. In
  comparison to a more traditional B tree the critbit tree is almost
  completely lockless.

Storage Types
-------------

The following storage types are available:

malloc
~~~~~~

syntax: malloc[,size]

malloc is a memory based backend.

file
~~~~

syntax: file[,path[,size[,granularity]]]

The file backend stores data in a file on disk. The file will be accessed using mmap.

persistent (experimental)
~~~~~~~~~~~~~~~~~~~~~~~~~

syntax: persistent,path,size

Persistent storage. Varnish will store objects in a file in a manner
that will secure the survival of *most* of the objects in the event of
a planned or unplanned shutdown of Varnish.


Management Interface
--------------------

If the -T option was specified, varnishd will offer a command-line
management interface on the specified address and port.  The
recommended way of connecting to the command-line management interface
is through varnishadm(1).

The commands available are documented in varnish(7).

Run-Time Parameters
-------------------

Runtime parameters are marked with shorthand flags to avoid repeating
the same text over and over in the table below.  The meaning of the
flags are:

experimental
      We have no solid information about good/bad/optimal values for
      this parameter.  Feedback with experience and observations are
      most welcome.

delayed
      This parameter can be changed on the fly, but will not take
      effect immediately.

restart
      The worker process must be stopped and restarted, before this
      parameter takes effect.

reload
      The VCL programs must be reloaded for this parameter to take effect.

Here is a list of all parameters, current as of last time we
remembered to update the manual page.  This text is produced from the
same text you will find in the CLI if you use the param.show command,
so should there be a new parameter which is not listed here, you can
find the description using the CLI commands.

Be aware that on 32 bit systems, certain default values, such as
workspace_client (=16k), thread_pool_workspace (=16k), http_resp_size
(=8k), http_req_size (=12k), gzip_stack_buffer (=4k) and
thread_pool_stack (=64k) are reduced relative to the values listed
here, in order to conserve VM space.

.. include:: params.rst

SEE ALSO
========

* varnish-cli(7)
* varnishlog(1)
* varnishhist(1)
* varnishncsa(1)
* varnishstat(1)
* varnishtop(1)
* vcl(7)

HISTORY
=======

The varnishd daemon was developed by Poul-Henning Kamp in cooperation
with Verdens Gang AS, Varnish Software AS and Varnish Software.

This manual page was written by Dag-Erling Smørgrav with updates by
Stig Sandbeck Mathisen ⟨ssm@debian.org⟩


COPYRIGHT
=========

This document is licensed under the same licence as Varnish
itself. See LICENCE for details.

* Copyright (c) 2007-2011 Varnish Software AS
