Varnish is a reverse proxy or http accelerator that uses serverside caching to increase the speed of servicing HTTP requests for use in things such as websites. 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.
Varnish uses Varnish Configuration Language (VCL). The VCL language is a small domain-specific language designed to be used to define request handling and document caching policies for the Varnish HTTP accelerator. When a new configuration is loaded, the varnishd management process translates the VCL code to C and compiles it to a shared object which is then dynamically linked into the server process.
Varnish uses two configuration file one is VCL and another one contains the values which will be passed as parametes to the varnishd.
/etc/default/varnish
# Configuration file for varnish # Main configuration file. You probably want to change itVARNISH_VCL_CONF=/etc/varnish/vcl.conf # Default address and port to bind to VARNISH_LISTEN_ADDRESS=0.0.0.0 VARNISH_LISTEN_PORT=80 # Telnet admin interface listen address and port VARNISH_ADMIN_LISTEN_ADDRESS=127.0.0.1 VARNISH_ADMIN_LISTEN_PORT=6082 # The minimum number of threads to start VARNISH_MIN_WORKER_THREADS=1 # Maximum number of worker threads or INF for unlimited VARNISH_MAX_WORKER_THREADS=2048 # Timeout value in seconds for threads to return VARNISH_WORKER_THREAD_TIMEOUT=5 # Hash algorithm to be used VARNISH_HASHOPTION=classic # Maximum size of the backend storagefile in bytes VARNISH_BACKEND_STORAGE_SIZE=10240000 VARNISH_BACKEND_STORAGE_FILE=/var/lib/varnish/varnish_storage.bin # Backend storage specification VARNISH_BACKEND_STORAGE="file,${VARNISH_BACKEND_STORAGE_FILE},${VARNISH_BACKEND_STORAGE_SIZE}" # Set default ttl in secounds VARNISH_TTL=120
/etc/varnish/vcl.conf
backend default {
# Our default backend, i.e. the web server
# You can use more than 1. See docs.
set backend.host = "0.0.0.0";
set backend.port = "8080"; # Web Server Port
}
sub vcl_recv {
if ((req.http.host ~ "^backend1..varnish.com") || (req.http.host ~ "^backend2.varnish.com")) {
pass;
} else {
if (req.request != "GET" && req.request != "HEAD") {
pipe;
}
if (req.request == "POST") {
pass;
}
if (req.request == "GET" && req.url ~ "\.(jpg|jpeg|gif|ico)$") {
lookup;
}
if (req.request == "GET" && req.url ~ "\.(css|js)$") {
lookup;
}
if (req.request == "GET" && req.url ~ "\.(php|html)$") {
lookup;
}
if (req.request == "GET") {
lookup;
}
lookup;
}
}
sub vcl_pipe {
pipe;
}
sub vcl_pass {
pass;
}
sub vcl_hit {
if (!obj.cacheable) {
pass;
}
if (req.http.Cookie) {
pass;
}
deliver;
}
sub vcl_miss {
fetch;
}
sub vcl_fetch {
if (!obj.valid) {
error;
}
if (!obj.cacheable) {
pass;
}
insert;
}
sub vcl_deliver {
deliver;
}
sub vcl_timeout {
discard;
}
sub vcl_discard {
discard;
}
You can use varnishstat to see the status of varnish
$ varnishstat client_conn 0 0.00 Client connections accepted client_req 0 0.00 Client requests received cache_hit 0 0.00 Cache hits cache_hitpass 0 0.00 Cache hits for pass cache_miss 0 0.00 Cache misses backend_conn 0 0.00 Backend connections success backend_fail 0 0.00 Backend connections failures backend_reuse 0 0.00 Backend connections reuses backend_recycle 0 0.00 Backend connections recycles backend_unused 0 0.00 Backend connections unused n_srcaddr 0 . N struct srcaddr n_srcaddr_act 0 . N active struct srcaddr n_sess_mem 1 . N struct sess_mem n_sess 1 . N struct sess n_object 0 . N struct object n_objecthead 0 . N struct objecthead n_smf 1 . N struct smf n_smf_frag 0 . N small free smf n_smf_large 1 . N large free smf n_vbe_conn 0 . N struct vbe_conn n_wrk 0 . N worker threads n_wrk_create 0 0.00 N worker threads created n_wrk_failed 0 0.00 N worker threads not created n_wrk_max 0 0.00 N worker threads limited n_wrk_queue 0 0.00 N queued work requests n_wrk_overflow 0 0.00 N overflowed work requests n_wrk_drop 0 0.00 N dropped work requests n_expired 0 . N expired objects n_deathrow 0 . N objects on deathrow losthdr 0 0.00 HTTP header overflows n_objsendfile 0 0.00 Objects sent with sendfile n_objwrite 0 0.00 Objects sent with write s_sess 0 0.00 Total Sessions s_req 0 0.00 Total Requests s_pipe 0 0.00 Total pipe s_pass 0 0.00 Total pass s_fetch 0 0.00 Total fetch s_hdrbytes 0 0.00 Total header bytes s_bodybytes 0 0.00 Total body bytes sess_closed 0 0.00 Session Closed sess_pipeline 0 0.00 Session Pipeline sess_readahead 0 0.00 Session Read Ahead sess_herd 0 0.00 Session herd shm_records 3480 0.67 SHM records shm_writes 3480 0.67 SHM writes shm_cont 0 0.00 SHM MTX contention sm_nreq 0 0.00 allocator requests sm_nobj 0 . outstanding allocations sm_balloc 0 . bytes allocated sm_bfree 10240000 . bytes free backend_req 0 0.00 Backend requests made
No Comment Received
Leave A Reply