NAMEvarnishd - HTTP accelerator daemon
SYNOPSISvarnishd [-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] [-u user] [-V] [-w min[,max[,timeout]]]
DESCRIPTIONThe 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.
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 type[,options] Use the specified storage backend. See Storage Types for a list of supported storage types. This option can be used multiple times to specify multiple storage files. -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. -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. -w min[,max[,timeout]] Start at least min but no more than max worker threads with the specified idle timeout. This is a shortcut for specifying the thread_pool_min, thread_pool_max and thread_pool_timeout run-time parameters. If only one number is specified, thread_pool_min and thread_pool_max are both set to this number, and thread_pool_timeout has no effect. 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[,size] Storage for each object is allocated with malloc(3). The size parameter specifies the maximum amount of memory varnishd will allocate. The size is assumed to be in bytes, unless followed by one of the following suffixes: K, k The size is expressed in kibibytes. M, m The size is expressed in mebibytes. G, g The size is expressed in gibibytes. T, t The size is expressed in tebibytes. The default size is unlimited. file[,path[,size[,granularity]]] Storage for each object is allocated from an arena backed by a file. This is the default. The path parameter specifies either the path to the backing file or the path to a directory in which varnishd will create the backing file. The default is /tmp. The size parameter specifies the size of the backing file. The size is assumed to be in bytes, unless fol- lowed by one of the following suffixes: K, k The size is expressed in kibibytes. M, m The size is expressed in mebibytes. G, g The size is expressed in gibibytes. T, t The size is expressed in tebibytes. % The size is expressed as a percentage of the free space on the file system where it resides. The default size is 50%. If the backing file already exists, it will be truncated or expanded to the specified size. Note that if varnishd has to create or expand the file, it will not pre-allocate the added space, leading to fragmentation, which may adversely impact performance. Pre-creating the storage file using dd(1) will reduce fragmentation to a minimum. The granularity parameter specifies the granularity of allocation. All allocations are rounded up to this size. The size is assumed to be in bytes, unless followed by one of the suffixes described for size except for %. The default size is the VM page size. The size should be reduced if you have many small objects. persistence[XXX] New, shiny, better. 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 sess_workspace (=16k) and thread_pool_stack (=64k) are reduced relative to the values listed here, in order to conserve VM space. acceptor_sleep_decay o Default: 0.900 o Flags: experimental If we run out of resources, such as file descriptors or worker threads, the acceptor will sleep between accepts. This parameter (multiplicatively) reduce the sleep duration for each succesfull accept. (ie: 0.9 = reduce by 10%) acceptor_sleep_incr o Units: s o Default: 0.001 o Flags: experimental If we run out of resources, such as file descriptors or worker threads, the acceptor will sleep between accepts. This parameter control how much longer we sleep, each time we fail to accept a new connection. acceptor_sleep_max o Units: s o Default: 0.050 o Flags: experimental If we run out of resources, such as file descriptors or worker threads, the acceptor will sleep between accepts. This parameter limits how long it can sleep between attempts to accept new connections. auto_restart o Units: bool o Default: on Restart child process automatically if it dies. ban_dups o Units: bool o Default: on Detect and eliminate duplicate bans. ban_lurker_sleep o Units: s o Default: 0.1 How long time does the ban lurker thread sleeps between successful attempts to push the last item up the ban list. It always sleeps a second when nothing can be done. A value of zero disables the ban lurker. between_bytes_timeout o Units: s o Default: 60 Default timeout between bytes when receiving data from backend. We only wait for this many seconds between bytes before giving up. A value of 0 means it will never time out. VCL can override this default value for each backend request and backend request. This parameter does not apply to pipe. cache_vbcs o Units: bool o Default: off o Flags: experimental Cache vbc's or rely on malloc, that's the question. cc_command o Default: exec gcc -std=gnu99 -DDIAGNOSTICS -pthread -fpic -shared -Wl,-x -o %o %s o Flags: must_reload Command used for compiling the C source code to a dlopen(3) loadable object. Any occurrence of %s in the string will be replaced with the source file name, and %o will be replaced with the output file name. cli_buffer o Units: bytes o Default: 8192 Size of buffer for CLI input. You may need to increase this if you have big VCL files and use the vcl.inline CLI command. NB: Must be specified with -p to have effect. cli_timeout o Units: seconds o Default: 10 Timeout for the childs replies to CLI requests from the master. clock_skew o Units: s o Default: 10 How much clockskew we are willing to accept between the backend and our own clock. connect_timeout o Units: s o Default: 0.4 Default connection timeout for backend connections. We only try to connect to the backend for this many seconds before giving up. VCL can override this default value for each backend and backend request. critbit_cooloff o Units: s o Default: 180.0 o Flags: experimental How long time the critbit hasher keeps deleted objheads on the cooloff list. default_grace o Units: seconds o Default: 10 o Flags: delayed Default grace period. We will deliver an object this long after it has expired, provided another thread is attempting to get a new copy. Objects already cached will not be affected by changes made until they are fetched from the backend again. default_ttl o Units: seconds o Default: 120 The TTL assigned to objects if neither the backend nor the VCL code assigns one. Objects already cached will not be affected by changes made until they are fetched from the backend again. To force an immediate effect at the expense of a total flush of the cache use "ban.url ." diag_bitmap o Units: bitmap o Default: 0 Bitmap controlling diagnostics code: 0x00000001 - CNT_Session states. 0x00000002 - workspace debugging. 0x00000004 - kqueue debugging. 0x00000008 - mutex logging. 0x00000010 - mutex contests. 0x00000020 - waiting list. 0x00000040 - object workspace. 0x00001000 - do not core-dump child process. 0x00002000 - only short panic message. 0x00004000 - panic to stderr. 0x00010000 - synchronize shmlog. 0x00020000 - synchronous start of persistence. 0x00040000 - release VCL early. 0x80000000 - do edge-detection on digest. System Message: WARNING/2 (../../doc/sphinx/reference/varnishd.rst:, line 376) Literal block ends without a blank line; unexpected unindent. Use 0x notation and do the bitor in your head :-) err_ttl o Units: seconds o Default: 0 The TTL assigned to the synthesized error pages esi_syntax o Units: bitmap o Default: 0 Bitmap controlling ESI parsing code: 0x00000001 - Don't check if it looks like XML 0x00000002 - Ignore non-esi elements 0x00000004 - Emit parsing debug records 0x00000008 - Force-split parser input (debugging) System Message: WARNING/2 (../../doc/sphinx/reference/varnishd.rst:, line 394) Literal block ends without a blank line; unexpected unindent. Use 0x notation and do the bitor in your head :-) expiry_sleep o Units: seconds o Default: 1 How long the expiry thread sleeps when there is nothing for it to do. Reduce if your expiry thread gets behind. fetch_chunksize o Units: kilobytes o Default: 128 o Flags: experimental The default chunksize used by fetcher. This should be bigger than the majority of objects with short TTLs. Internal limits in the storage_file module makes increases above 128kb a dubious idea. first_byte_timeout o Units: s o Default: 60 Default timeout for receiving first byte from backend. We only wait for this many seconds for the first byte before giving up. A value of 0 means it will never time out. VCL can override this default value for each backend and backend request. This parameter does not apply to pipe. group o Default: magic o Flags: must_restart The unprivileged group to run as. gzip_level o Default: 6 Gzip compression level: 0=debug, 1=fast, 9=best gzip_stack_buffer o Units: Bytes o Default: 32768 o Flags: experimental Size of stack buffer used for gzip processing. The stack buffers are used for in-transit data, for instance gunzip'ed data being sent to a client.Making this space to small results in more overhead, writes to sockets etc, making it too big is probably just a waste of memory. gzip_tmp_space o Default: 0 o Flags: experimental Where temporary space for gzip/gunzip is allocated: 0 - malloc 1 - session workspace 2 - thread workspace System Message: WARNING/2 (../../doc/sphinx/reference/varnishd.rst:, line 444) Literal block ends without a blank line; unexpected unindent. If you have much gzip/gunzip activity, it may be an advantage to use workspace for these allocations to reduce malloc activity. Be aware that gzip needs 256+KB and gunzip needs 32+KB of workspace (64+KB if ESI processing). http_gzip_support o Units: bool o Default: on o Flags: experimental Enable gzip support. When enabled Varnish will compress uncompressed objects before they are stored in the cache. If a client does not support gzip encoding Varnish will uncompress compressed objects on demand. Varnish will also rewrite the Accept-Encoding header of clients indicating support for gzip to: Accept-Encoding: gzip Clients that do not support gzip will have their Accept-Encoding header removed. For more information on how gzip is implemented please see the chapter on gzip in the Varnish reference. Note: Enabling gzip on a running Varnish instance using ESI can yield content where cached, uncompressed pages have compressed ESI elements. To avoid this, either ban all ESI-related elements before enabling gzip, or restart Varnish. http_headers o Units: header lines o Default: 64 Maximum number of HTTP headers we will deal with. This space is preallocated in sessions and workthreads only objects allocate only space for the headers they store. http_range_support o Units: bool o Default: off o Flags: experimental Enable support for HTTP Range headers. listen_address o Default: :80 o Flags: must_restart Whitespace separated list of network endpoints where Varnish will accept requests. Possible formats: host, host:port, :port listen_depth o Units: connections o Default: 1024 o Flags: must_restart Listen queue depth. log_hashstring o Units: bool o Default: off Log the hash string to shared memory log. log_local_address o Units: bool o Default: off Log the local address on the TCP connection in the SessionOpen shared memory record. lru_interval o Units: seconds o Default: 2 o Flags: experimental Grace period before object moves on LRU list. Objects are only moved to the front of the LRU list if they have not been moved there already inside this timeout period. This reduces the amount of lock operations necessary for LRU list access. max_esi_includes o Units: includes o Default: 5 Maximum depth of esi:include processing. max_restarts o Units: restarts o Default: 4 Upper limit on how many times a request can restart. Be aware that restarts are likely to cause a hit against the backend, so don't increase thoughtlessly. ping_interval o Units: seconds o Default: 3 o Flags: must_restart Interval between pings from parent to child. Zero will disable pinging entirely, which makes it possible to attach a debugger to the child. pipe_timeout o Units: seconds o Default: 60 Idle timeout for PIPE sessions. If nothing have been received in either direction for this many seconds, the session is closed. prefer_ipv6 o Units: bool o Default: off Prefer IPv6 address when connecting to backends which have both IPv4 and IPv6 addresses. queue_max o Units: % o Default: 100 o Flags: experimental Percentage permitted queue length. This sets the ratio of queued requests to worker threads, above which sessions will be dropped instead of queued. rush_exponent o Units: requests per request o Default: 3 o Flags: experimental How many parked request we start for each completed request on the object. NB: Even with the implict delay of delivery, this parameter controls an exponential increase in number of worker threads. saintmode_threshold o Units: objects o Default: 10 o Flags: experimental The maximum number of objects held off by saint mode before no further will be made to the backend until one times out. A value of 0 disables saintmode. send_timeout o Units: seconds o Default: 600 o Flags: delayed Send timeout for client connections. If no data has been sent to the client in this many seconds, the session is closed. See setsockopt(2) under SO_SNDTIMEO for more information. sess_timeout o Units: seconds o Default: 5 Idle timeout for persistent sessions. If a HTTP request has not been received in this many seconds, the session is closed. sess_workspace o Units: bytes o Default: 65536 o Flags: delayed Bytes of HTTP protocol workspace allocated for sessions. This space must be big enough for the entire HTTP protocol header and any edits done to it in the VCL code. Minimum is 1024 bytes. session_linger o Units: ms o Default: 50 o Flags: experimental How long time the workerthread lingers on the session to see if a new request appears right away. If sessions are reused, as much as half of all reuses happen within the first 100 msec of the previous request completing. Setting this too high results in worker threads not doing anything for their keep, setting it too low just means that more sessions take a detour around the waiter. session_max o Units: sessions o Default: 100000 Maximum number of sessions we will allocate before just dropping connections. This is mostly an anti-DoS measure, and setting it plenty high should not hurt, as long as you have the memory for it. shm_reclen o Units: bytes o Default: 255 Maximum number of bytes in SHM log record. Maximum is 65535 bytes. shm_workspace o Units: bytes o Default: 8192 o Flags: delayed Bytes of shmlog workspace allocated for worker threads. If too big, it wastes some ram, if too small it causes needless flushes of the SHM workspace. These flushes show up in stats as "SHM flushes due to overflow". Minimum is 4096 bytes. shortlived o Units: s o Default: 10.0 Objects created with TTL shorter than this are always put in transient storage. syslog_cli_traffic o Units: bool o Default: on Log all CLI traffic to syslog(LOG_INFO). thread_pool_add_delay o Units: milliseconds o Default: 20 o Flags: experimental Wait at least this long between creating threads. Setting this too long results in insuffient worker threads. Setting this too short increases the risk of worker thread pile-up. thread_pool_add_threshold o Units: requests o Default: 2 o Flags: experimental Overflow threshold for worker thread creation. Setting this too low, will result in excess worker threads, which is generally a bad idea. Setting it too high results in insuffient worker threads. thread_pool_fail_delay o Units: milliseconds o Default: 200 o Flags: experimental Wait at least this long after a failed thread creation before trying to create another thread. Failure to create a worker thread is often a sign that the end is near, because the process is running out of RAM resources for thread stacks. This delay tries to not rush it on needlessly. If thread creation failures are a problem, check that thread_pool_max is not too high. It may also help to increase thread_pool_timeout and thread_pool_min, to reduce the rate at which treads are destroyed and later recreated. thread_pool_max o Units: threads o Default: 500 o Flags: delayed, experimental The maximum number of worker threads in all pools combined. Do not set this higher than you have to, since excess worker threads soak up RAM and CPU and generally just get in the way of getting work done. thread_pool_min o Units: threads o Default: 5 o Flags: delayed, experimental The minimum number of threads in each worker pool. Increasing this may help ramp up faster from low load situations where threads have expired. Minimum is 2 threads. thread_pool_purge_delay o Units: milliseconds o Default: 1000 o Flags: delayed, experimental Wait this long between purging threads. This controls the decay of thread pools when idle(-ish). Minimum is 100 milliseconds. thread_pool_stack o Units: bytes o Default: -1 o Flags: experimental Worker thread stack size. On 32bit systems you may need to tweak this down to fit many threads into the limited address space. thread_pool_timeout o Units: seconds o Default: 300 o Flags: delayed, experimental Thread idle threshold. Threads in excess of thread_pool_min, which have been idle for at least this long are candidates for purging. Minimum is 1 second. thread_pools o Units: pools o Default: 2 o Flags: delayed, experimental Number of worker thread pools. Increasing number of worker pools decreases lock contention. Too many pools waste CPU and RAM resources, and more than one pool for each CPU is probably detrimal to performance. Can be increased on the fly, but decreases require a restart to take effect. thread_stats_rate o Units: requests o Default: 10 o Flags: experimental Worker threads accumulate statistics, and dump these into the global stats counters if the lock is free when they finish a request. This parameters defines the maximum number of requests a worker thread may handle, before it is forced to dump its accumulated stats into the global counters. user o Default: magic o Flags: must_restart The unprivileged user to run as. Setting this will also set "group" to the specified user's primary group. vcc_err_unref o Units: bool o Default: on Unreferenced VCL objects result in error. vcl_dir o Default: /usr/local/etc/varnish Directory from which relative VCL filenames (vcl.load and include) are opened. vcl_trace o Units: bool o Default: off Trace VCL execution in the shmlog. Enabling this will allow you to see the path each request has taken through the VCL program. This generates a lot of logrecords so it is off by default. vmod_dir o Default: /usr/local/lib/varnish/vmods Directory where VCL modules are to be found. waiter o Default: default o Flags: must_restart, experimental Select the waiter kernel interface.
SEE ALSOo varnishlog(1) o varnishhist(1) o varnishncsa(1) o varnishstat(1) o varnishtop(1) o vcl(7)
HISTORYThe 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 Smorgrav with updates by Stig Sandbeck Mathisen <email@example.com>
COPYRIGHTThis document is licensed under the same licence as Varnish itself. See LICENCE for details. o Copyright (c) 2007-2011 Varnish Software AS
AUTHORDag-Erling Smorgrav, Stig Sandbeck Mathisen, Per Buer VARNISHD(1)