Ein kurzer Blick auf effizientes Web-Caching. Nils Goroll (BILD GmbH & Co. KG / UPLEX)

1. Varnish kann Alles
8. Juli 2015
Nils Goroll

2. Varnish kann Alles
in 25 Minuten
8. Juli 2015
Nils Goroll

3. Varnish kann Alles
in 25 Minuten
8. Juli 2015
Nils Goroll
ein kurzer Blick aufein kurzer Blick auf
effizientes Web-Cachingeffizientes Web-Caching

4. Setup Reverse Proxy
● + Caching
● Keine Generierung von Inhalten

5. Effizienz!
● Bild home von Varnish – System Call Trace
1436329479.806468 getsockname(17, {sa_family=AF_INET6, sin6_port=htons(8080), inet_pton(AF_INET6, "::1",
&sin6_addr), sin6_flowinfo=0, sin6_scope_id=0}, [28]) = 0
1436329479.806645 setsockopt(17, SOL_SOCKET, SO_LINGER, {onoff=0, linger=0}, 8) = 0
1436329479.806718 setsockopt(17, SOL_SOCKET, SO_KEEPALIVE, [1], 4) = 0
1436329479.806762 setsockopt(17, SOL_TCP, TCP_NODELAY, [1], 4) = 0
1436329479.806804 ioctl(17, FIONBIO, [0]) = 0
1436329479.806854 ioctl(17, FIONBIO, [0]) = 0
1436329479.806888 poll([{fd=17, events=POLLIN}], 1, 50) = 1 ([{fd=17, revents=POLLIN}])
1436329479.806938 read(17, "GET / HTTP/1.1rnUser-Agent: curl"..., 32767) = 75
1436329479.807612 writev(17, [{"HTTP/1.1", 8}, {" ", 1}, {"200", 3}, {" ", 1}, {"OK", 2}, {"rn", 2}, {"Content-
Type: text/html;charset="..., 37}, {"rn", 2}, {"Content-Language: de-DE", 23}, {"rn", 2}, {"Last-Modified:
Wed, 08 Jul 2015 "..., 44}, {"rn", 2}, {"X-UA-Compatible: IE=Edge,chrome="..., 33}, {"rn", 2}, {"X-Refresh:
h=23|g=103975.000|c=G"..., 98}, {"rn", 2}, {"Server: Apache", 14}, {"rn", 2}, {"Cache-Control: public, max-
age=3"..., 33}, {"rn", 2}, {"Expires: Wed, 08 Jul 2015 04:25:"..., 38}, {"rn", 2}, {"Date: Wed, 08 Jul 2015
04:24:38 "..., 35}, {"rn", 2}, {"Vary: Accept-Encoding", 21}, {"rn", 2}, {"X-Cache: MISS from non_disclosed",
32}, {"rn", 2}, {"X-Cache-Lookup: MISS from non_di"..., 44}, {"rn", 2}, {"Via: 1.0 non_disclosed:3128
(squ"..., 35}, {"rn", 2}, ...], 46) = 33415
1436329479.808307 writev(17, [{" href="/reise/startseite/reise/r"..., 32768}], 1) = 32768
1436329479.808803 writev(17, [{"n>Ruland 342200236Manta, Manta 2342200234?</"..., 32768}], 1) = 32768
1436329479.809250 writev(17, [{" "..., 32768}], 1) = 32768
1436329479.809745 writev(17, [{"ss="kicker">Land Rover</span>n "..., 32768}], 1) = 32768
1436329479.810218 writev(17, [{"d.gif" data-img-src="http://bild"..., 32768}], 1) = 32768
1436329479.810640 writev(17, [{"echenland-gabriel_46440882-14362"..., 32768}], 1) = 32768
1436329479.811115 writev(17, [{".de/fotos/ondemand-23661532/Bild"..., 32768}], 1) = 32768
1436329479.811643 writev(17, [{"e2=' + window.location.pathname"..., 32768}], 1) = 32768
1436329479.811873 writev(17, [{"/faq-artikel-web/bildplus/faq-we"..., 6500}], 1) = 6500
1436329479.811979 poll([{fd=17, events=POLLIN}], 1, 50) = 1 ([{fd=17, revents=POLLIN}])
1436329479.839042 read(17, "", 32767) = 0
1436329479.839113 close(17) = 0
● 21 syscalls, ~12 minimum, 32ms von Anfang
bis Ende (cache hit)

6. Laptop als bild.de
Server
ab -H 'Accept-Encoding: gzip' -H 'Host:
www.bild.de' -c 1000 -n 100000 localhost:8080/
...
Requests per second: 18175.82 [#/sec] (mean)
Time per request: 55.018 [ms] (mean)
Time per request: 0.055 [ms] (mean,
across all concurrent requests)
Transfer rate: 969279.78 [Kbytes/sec]
received

7. Varnish Performance
● Massiv multihreaded
● Moderne kernel-Interfaces
● mmap()
● event-interfaces Linux kqueues / Solaris ports
● 64bit
● Lock-freie Datenstrukturen
● Gzip-offload (seit 3.x)

8. Früher war alles
besser

9. Konfiguration
● Einige globale Parameter
● Kein klassisches Config-File
● Konfiguration ist CODE
● Kompilierung: VCL → C → Maschinencode
● Shared object („library“) → zur Laufzeit
ersetzen
● VCL subs = Hooks

10. VCL
sub recv_pool_www_special {
# redirect all .bto content to .bild
if (req.url ~ "^(.*).bto.([^.][^.]*)$") {
# redirect to .bild.suffix
set req.http.Location = "http://" req.http.Host
pmatch.1 ".bild." pmatch.2;
error 701 "Moved Permanently (bto)";
}
call recv_pool_www_xmli;
if (req.url ~ "^/no_url|^/gadget/version.xml") {
error 410;
}
}

11. In-line C
C{
time_t tnow, tcheck;
const time_t max_diff = 30;
time(&tnow);
tcheck = atol(VRT_r_pmatch(sp, &local_pmatch, 3));
if (labs(tnow - tcheck) > max_diff) {
VRT_error(sp, 400, "G2O time delta exceeded");
VRT_done(sp, VCL_RET_ERROR);
}
}C

12. VMODs
● VCL:
set req.http.X-DeviceClass =
dcs.type_class(dcs.classify());
● VMOD:
VCL_STRING vmod_type_class(dcs_ctx *ctx, VCL_INT e)
{
const VCL_INT t = dcs_match_type_id(e);
(void) ctx;
return dcs_type_class(t > 0 ? t : 0);
}
// ~
VCL_INT vmod_classify(dcs_ctx *ctx) {
return dcs_varnish_classify(ctx);
}

13. Custom-Entwicklung für bild.de
● BildPlus: Paywall / Vauth
● Video Token Service
● Addefend Integration
● Bilder URL-Normalisierung / Parameter Check
● Akamai G2O
● URL-Kanonifizierung

14. Custom-Entwicklung für bild.de
● VSLP Director
● Clustering
● Backend Conditional Requests

15. VSLP Director
● Varnish Stateless Persistence Director
● Sharding über Backends
● Bei 404 Objekt vom „frischen“ Backend
holen
cobildweb212
cobildweb218
cobildweb221
cobildcache101
Server-ids beispielhaft

16. Clustering
cobildcache101
cobildcache102
cobildcache103
cobildcache104
cobildcache105
cobildcache106
cobildcache107
cobildcache108
cobildweb212
cobildweb218
cobildweb221
Server-ids beispielhaft

17. Backend Conditional
Requests
●
If­Modified­Since und/oder If­None­Match
→ Backend
● Abgelaufene Objekte für eine begrenzte Zeit
im Cache behalten (keep).
● Konditionaler Request ans Backend, falls
Last­Modified und/oder Etag vorhanden
● UPLEX Entwicklung war experimenteller
Branch
● Default seit 4.0

18. Varnish bei bild.de
● Konfig-Generierung

19. Konfig-Generierung
● Warum?
● 11 verschiedene Server
– 8 prod
– X dev (war: 7, jetzt 1, In Zukunft ?)
– 1 stage
● Features an- und abschalten
● Varnish4 Migration aus einer Basis

20. Konfig-Generierung
● VCL
if (($ROLE == ROLE_STAGE) &&
$FEATURE[FEAT_STAGE_PROTECT]) {
VCL <<EOF;
sub vcl_recv {
unset req.http.X-Auth-Saved;
if (! (client.ip ~ relaunch_ip )) {
...

21. Konfig-Generierung
● Perl generiert VCL
● my %vservernames_bypool = (
"sport" => [
"www.ein-herz-fuer-kinder.de",
"sportbild.bild.de",
"tv.device.bild.de",
],
"ssl_channelizer" => [
"ssl-channelizer.bild.de",
]);
● VCL gen_pseudonyms_code(%vservernames_bypool,
sub { ("set req.http.X-V-Pool = "". $_[0]."";n".
"tcall vcl_recv_pool_". $_[0].";");
});

22. Konfig-Generierung
...
else if ((req.http.host == "www.ein-herz-fuer-kinder.de") ||
(req.http.host == "sportbild.bild.de") ||
(req.http.host == "tv.device.bild.de")) {
set req.http.X-V-Pool = "sport";
call vcl_recv_pool_sport;
}
else if ((req.http.host == "ssl-channelizer.bild.de")) {
set req.http.X-V-Pool = "ssl_channelizer";
call vcl_recv_pool_ssl_channelizer;
}
...

23. ABER
Bild.de läuft noch auf unserem Varnish 2.0.3
fork
:-(
● Migration auf 4.1 / master RSN

24. Danke!
Fragen?
● nils.goroll@uplex.de, +49-170-2723133