I have 2 backends in my Varnish configuration: one dynamic server and one static server.
The configuration for the backends is as follows:
backend default {
.host = "127.0.0.1";
.port = "8484";
.probe = {
.interval = 5s;
.timeout = 1s;
.window = 5;
.threshold = 3;
}
}
backend default_1 {
.host = "127.0.0.1";
.port = "8181";
.probe = {
.interval = 5s;
.timeout = 1s;
.window = 5;
.threshold = 3;
}
}
When i am trying to restart the Varnish server it fails to restart.
What could be the issue?
If you declare a backend, you need to use it : it is how Varnish does.
Anyway, you have several solutions to your issue. The prefered one is maybe to still declare unused backend in your VCL, run Varnish, while you will convert error into warnings by adding the parameter -p vcc_err_unref=off
Related
I am using thumbor and s3.
I want to use varnish infront of them.
I know how to do place varnish in each of them but I can't combine the two
varnish setup for thumbor
vcl 4.0;
import directors;
backend thumbor1 { .host ="127.0.0.1"; .port="8888"; .max_connections = 200; .connect_timeout = 5s; .between_bytes_timeout = 5s; }
# backend thumbor2 { .host ="127.0.0.1"; .port="9002"; .max_connections = 200; .connect_timeout = 5s; .between_bytes_timeout = 5s; }
acl internal {
"localhost";
"127.0.0.1";
}
sub vcl_init {
new vdir = directors.round_robin();
vdir.add_backend(thumbor1);
# vdir.add_backend(thumbor2);
}
sub vcl_recv {
set req.backend_hint = vdir.backend();
if (req.method == "PURGE") {
if (!client.ip ~ internal) {
return (synth(405, "This IP is not allowed to send PURGE requests."));
}
return (purge);
}
if (req.url ~ "\?$") {
set req.url = regsub(req.url, "\?$", "");
}
return (hash);
}
varnish setup for s3
vcl 4.0;
backend default
{
.host = "my.bucket.s3.amazonaws.com";
.port = "80";
}
sub vcl_backend_fetch
{
set bereq.http.Host = "my.bucket.s3.amazonaws.com";
set bereq.http.Date = now;
}
I'd like the final result would be something like
client => varnish => thumbor => s3 (thumbnail image)
client => varnish => s3 (normal image)
You should put 2 backend blocks in the one file. Then in the vcl_recv you should set which backend do you want by some header, url path etc.
To set which backend to use, you could use:
set req.backend_hint = thumbor1;
# Or
set req.backend_hint = default;
There you could find how I've applied it to use 2 backends - localhost:3000 & localhost:8080: https://github.com/new-fantastic/vsf-cache-varnish/blob/master/docker/varnish/shared.vcl
Is it possible to use varnish-counters in VCL in conditions?
I would like to write a condition based on current value of MAIN.backend_conn but I cannot figure out, whether can I use statistics in VCL even in inline C.
Current Solution
Now I am using configuration like this:
backend default {
.host = "192.168.122.11";
.probe = {
.url = "/check-connections.php";
.interval = 1s;
.threshold = 4;
}
}
backend sessionWorker {
.host = "192.168.122.11";
.probe = {
.url = "/other-probe";
.interval = 5s;
.threshold = 2;
}
}
sub vcl_recv {
if (req.http.cookie ~ "(^|;\s*)(SESS=)" || std.healthy(req.backend_hint)) {
set req.backend_hint = sessionWorker;
} else {
return (synth(503, "Server overloaded"));
}
}
check-connections.php reads nginx status - active connections and triggers an error, if there are more active connections:
if ($active > 10) {
http_response_code(502);
} else {
http_response_code(200);
}
I would like to find a solution how to replace std.healty(req.backend_hint) with current connections (VBE.conn) to the backend directly in the VCL.
There are some counters implemented already. Like bereq.retries:
sub vcl_backend_response {
if (beresp.status == 503 && bereq.retries < 5 ) {
return(retry);
}
}
sub vcl_backend_error {
if (beresp.status == 503 && bereq.retries == 5) {
synthetic(std.fileread("/path/to/my/file/varnish503.html"));
return(deliver);
}
}
Maybe this is already what you need. Otherwise here is a list of other build in counters.
I want to use the Varnish 4.0.3.
And I want to divide the caching process whether cookie has specific key and value.
When user comes to mypage, if their browser has "loged_in=true" cookie, I do NOT want to cache the page.
Also if it doesn't have the cookie, I want to cache the mypage.
But both settings are not working.
It doesn't cache at all.
Additionaly, when user comes to the "category" page, the varnish caches the page correctly.
Here is my default.vcl.
Does anyone tell me what's wrong with me ?
vcl 4.0;
import directors;
backend ap1 {
.host = "192.168.0.1";
.port = "80";
.first_byte_timeout = 200s;
.probe = {
.url = "/";
.interval = 5s;
.timeout = 1 s;
.window = 5;
.threshold = 3;
.initial = 1;
}
}
backend ap2 {
.host = "192.168.0.2";
.port = "80";
.first_byte_timeout = 200s;
.probe = {
.url = "/";
.interval = 5s;
.timeout = 1 s;
.window = 5;
.threshold = 3;
.initial = 1;
}
}
sub vcl_init{
new ws_hash = directors.hash();
ws_hash.add_backend(ap1, 1.0);
ws_hash.add_backend(ap2, 1.0);
new ws_rand = directors.random();
ws_rand.add_backend(ap1, 1.0);
ws_rand.add_backend(ap2, 1.0);
}
sub vcl_recv{
if( (req.url ~ "(category)") ) {
// Cache
set req.backend_hint = ws_hash.backend(req.url + ":" + req.http.host);
return(hash);
}
if( (req.url ~ "(mypage)") ) {
if (req.http.Cookie ~ "(loged_in=true)" ) {
// NO Cache
set req.backend_hint = ws_rand.backend();
return(pass);
}
// Cache
set req.backend_hint = ws_hash.backend(req.url + ":" + req.http.host);
return(hash);
}
// NO Cache
set req.backend_hint = ws_rand.backend();
return(pass);
}
sub vcl_deliver {
if (obj.hits > 0) {
set resp.http.V-Cache = "HIT";
} else {
set resp.http.V-Cache = "MISS";
}
}
So I'm running a website, on the front it's a simple Apache home page nothing important. But I want to run a sync client on a sub domain
backend apache {
.host = "127.0.0.1";
.port = "8051";
.connect_timeout = 1s;
}
backend node {
.host = "127.0.0.1";
.port = "8081";
.connect_timeout = 1s;
}
backend bot {
.host = "127.0.0.1";
.port = "8080";
.connect_timeout = 1s;
}
sub vcl_recv {
if(req.http.host == "Base-domain.com") {
set req.backend = apache;
}
if(req.http.host == "bot.base-domain.com") {
set req.backend = bot;
}
if(req.http.host == "sync.base-domain.com") {
set req.backend = node;
}
if (req.http.Upgrade ~ "(?i)websocket") {
set req.backend = node;
return (pipe);
}
if (req.http.host == "sync.based-domain.moe") {
if (req.url ~ "^/socket.io/") {
set req.backend = node;
return (pipe);
}
return (pass);
}
}
sub vcl_pipe {
if (req.http.upgrade) {
set bereq.http.upgrade = req.http.upgrade;
}
}
Searching all over for information on how to run the node JS as the one with a socket is turning up no help. Due to a connection issue the websocket is on 1338 rather than 1337. Pretty new to this so not sure what to do.
Should I be changing my varnish or modification the node's config further? Thanks in advance.
We have a set of 6 backends that serve our website. Because we use multiple datacenters we have found the best performance occurs for us when we have varnish send the request to the localhost httpd server (running on port 81). This of course is a very basic configuration well supported by varnish and can be accomplished using the fallback director:
director default fallback {
{ .backend = localbackend; }
{ .backend = web1; }
{ .backend = web2; }
{ .backend = web3; }
etc...
}
However the fallback director tries the other backends in order till it finds a healthy one. The BIG problem is that in the above config web1 will take all the traffic if localbackend fails !!! This will overload web1 and it will become sick. Then all requests go to web3... and now it will get 3x the normal traffic... cause a cascading failure.
Thus we need instead a config that will allow all requests to sent to the localhost httpd server if it is health, but if not, send the requests to the other healthy servers in a round robin type fashion.
Thank you in advance for any suggestions and solutions you might think of... Your help is GREATLY appreciated.
It can be accomplished in several ways, one of the simplest is:
Set localhost as default backend
Create a round robind director for the rest of backends
Check on top of your vcl_recv if default backend is healthy and if it isn't switch to round robind director.
With this approach you can even switch backends if current request has failed.
Something like:
probe my_probe {
.url = "/";
.interval = 1s;
.timeout = 0.2 s;
.window = 3;
.threshold = 2;
.initial = 1;
}
backend default {
.host = 127.0.0.1;
.probe = my_probe;
}
backend server1 {
.host = 192.168.8.21;
.probe = my_probe;
}
backend server2 {
.host = 192.168.8.22;
.probe = my_probe;
}
backend server3 {
.host = 192.168.8.23;
.probe = my_probe;
}
director server_pool round-robin {
{ .backend = server1; }
{ .backend = server2; }
{ .backend = server3; }
}
sub vcl_recv {
if ( req.backend == default
&& ! req.backend.healthy
) {
set req.backend = server_pool;
}
/* Uncomment if you want to divert restarted requests to the server pool
* if (req.restarts > 0) {
* set req.backend = server_pool;
* }
*/
}
This is completely untested, but should theoretically work.
probe healthcheck {
.url = "/status.php";
.interval = 60s;
.timeout = 0.3 s;
.window = 8;
.threshold = 3;
.initial = 3;
.expected_response = 200;
}
backend server1 {
.host = "server1.example.com";
.probe = healthcheck;
}
backend server2 {
.host = "server2.example.com";
.probe = healthcheck;
}
backend server3 {
.host = "server3.example.com";
.probe = healthcheck;
}
director fallback round-robin {
{ .backend = server1; }
{ .backend = server2; }
{ .backend = server3; }
}
sub vcl_recv {
# Set backend to fallback director until we find the proper localhost backend.
# If we can't figure out which is localhost, at least we still work.
set req.backend = fallback;
# Set the default backend to localhost by hostname
if (server.hostname == "server1") {
set req.backend = server1;
set obj.http.X-LocalCache = "YES";
}
else if (server.hostname == "server2") {
set req.backend = server2;
set obj.http.X-LocalCache = "YES";
}
else if (server.hostname == "server3") {
set req.backend = server3;
set obj.http.X-LocalCache = "YES";
}
# If the localhost fails, go to fallback director.
if (obj.http.X-LocalCache ~ "YES") {
if (!req.backend.healthy) {
set req.backend = fallback;
unset obj.http.X-LocalCache
}
}
}
It will automatically figure out which backend is localhost by using the hostname. You just have to make sure the backend names match your hostnames.
You can do some basic load balancing with Varnish. Check this out:
https://www.varnish-cache.org/trac/wiki/LoadBalancing