ApacheCon 2017: What's new in httpd 2.4

Jim Jagielski
@jimjag
Apache httpd v2.4:
What’s New,
Pussycat?
This should
be pretty good!

About Me
➡ Apache Software Foundation
➡ Co-founder, Director, Member and Developer
➡ Director
➡ Outercurve, MARSEC-XL, OSSI, OSI (ex)…
➡ Developer
➡ Mega FOSS projects
➡ O’Reilly Open Source Award: 2013
➡ European Commission: Luminary Award
➡ Sr. Director: Tech Fellows: Capital One
@jimjag
This work is licensed under a Creative Commons Attribution 3.0 Unported License. - Jim Jagielski - @jimjag

Hold on a tic
➡ How do you define “new”??
@jimjag

httpd is sooo old school (aka
fud)
➡ Apache doesn’t scale (its SLOW)
➡ http://www.youtube.com/watch?v=bzkRVzciAZg 
 
➡ Apache is too generalized 
 
 
➡ Apache is too complex (config file)
➡ really?
➡ Apache is too old 
(yeah, just like Linux)
@jimjag
vs
It’s Squagels!

Apache httpd 2.4 - design drivers
➡ New features and improve old ones
➡ Support for async I/O w/o dropping support for older
systems
➡ Larger selection of usable MPMs: added Event, Motorz,
etc...
➡ Leverage higher-performant versions of APR
➡ Increase performance
➡ Reduce memory utilization
➡ The Cloud
@jimjag
Currently at version 2.4.25 (2.4.1 went GA Feb 21, 2012)

What’s New: Apache httpd 2.4
➡ Configuration / Runtime Improvements
➡ New Modules / Capabilities
➡ Cloud / Proxy Enhancements
➡ Performance Increases
➡ HTTP/2
@jimjag

Conﬁguration - Runtime
➡ mod_macro
@jimjag
<Macro VHost $name $domain>
<VirtualHost *:80>
ServerName $domain
ServerAlias www.$domain
DocumentRoot /var/www/vhosts/$name
ErrorLog /var/log/httpd/$name.error_log
CustomLog /var/log/httpd/$name.access_log combined
</VirtualHost>
</Macro>
Use VHost example example.com
Use VHost myhost hostname.org
Use VHost apache apache.org
UndefMacro VHost
From my
ApacheCon 2000
Preso

➡ <If> supports per-request conditions
@jimjag
# Compare the host name to example.com and
# redirect to www.example.com if it matches
<If "%{HTTP_HOST} == 'example.com'">
Redirect permanent / http://www.example.com/
<ElseIf "%{HTTP_HOST} == ‘foobarfoo.com'">
Redirect permanent / http://www2.example.com/
</If>

➡ Simple config-file variables: <Define>
@jimjag
<IfDefine TEST>
Define servername test.example.com
</IfDefine>
<IfDefine !TEST>
Define servername www.example.com
Define SSL
</IfDefine>
DocumentRoot /var/www/${servername}/htdocs

➡ Finer control of timeouts, esp. during requests
➡ mod_reqtimeout
➡ KeepAliveTimout down to the millisecond
➡ Finer control over logging
➡ per module/per directory
➡ new logging levels (TRACE[1-8])
@jimjag
LogLevel info ssl:warn
<Directory "/usr/local/apache/htdocs/foo">
LogLevel debug
</Directory>

➡ Other stuff:
➡ No more NameVirtualHost
➡ General purpose expression parser (BNF compatible)
➡ AllowOverrideList 
 
 
➡ Loadable MPM modules
➡ Recall that different MPMs have different config directives!
@jimjag
AllowOverride None
AllowOverrideList Redirect RedirectMatch Header
./configure —enable-mpms-shared=all
LoadModule mpm_event_module modules/mod_mpm_event.so

➡ Require
➡ Removes order deny/allow insanity!
➡ mod_access_compat for backwards combat
@jimjag
AuthType Basic
AuthName "Restricted Resource"
AuthBasicProvider file
AuthUserFile /web/users
AuthGroupFile /web/groups
Require group admin
<Directory /www/docs>
<RequireAll>
Require group alpha beta
Require not group reject
</RequireAll>
</Directory>
<Directory /www/docs2>
Require all granted
</Directory>

New Modules
➡ mod_lua
@jimjag
<Files *.lua>
SetHandler lua-script
</Files>
…
example.lua
require "string"
function handle(r)
r.content_type = "text/plain"
if r.method == 'GET' then
r:puts("Hello Lua World!n")
for k, v in pairs( r:parseargs() ) do
r:puts( string.format("%s: %sn", k, v) )
end
elseif r.method == 'POST' then
r:puts("Hello Lua World!n")
for k, v in pairs( r:parsebody() ) do
r:puts( string.format("%s: %sn", k, v) )
end
elseif r.method == 'PUT' then
r:puts("Unsupported HTTP method " .. r.method)
r.status = 405
return apache2.ok
else
return 501
end
return apache2.OK
end

New Modules
➡ mod_buffer
➡ buffer the i/o stacks w/i httpd
➡ mod_sed
➡ True sed functionality, alternate to mod_substitute 
 
 
 
 
➡ mod_remoteip
➡ allow access to the real client IP address
@jimjag
<Directory "/var/www/docs/status">
AddOutputFilter Sed html
OutputSed "s/complete/DONE/g"
OutputSed “s/in-progress/TODO/g"
</Directory>
RemoteIPHeader X-Client-IP

New Modules
➡ mod_session
➡ easily maintain application server state
➡ mod_auth_form
➡ Form-based auth can now be handled internally
@jimjag
<Location /dologin.html>
SetHandler form-login-handler
AuthFormLoginRequiredLocation http://example.com/login.html
AuthFormLoginSuccessLocation http://example.com/success.html
AuthFormProvider file
AuthUserFile conf/passwd
AuthType form
AuthName realm
Session On
SessionCookieName session path=/
SessionCryptoPassphrase secret
</Location>

New Modules
➡ mod_log_debug
➡ Add debug logging at any hook 
 
 
 
➡ mod_ratelimit
➡ (basic) bandwidth limiting for clients
@jimjag
<Location /foo>
LogMessage “subreq to foo” hook=type_checker expr=%{IS_SUBREQ}
</Location>
<Location /downloads>
SetOutputFilter RATE_LIMIT
SetEnv rate-limit 400
</Location>

Even more!
➡ mod_cache
➡ Can serve stale data if required
➡ X-Cache-Header now supports HIT/MISS/
REVALIDATE
➡ Can cache HEAD
➡ htcacheclean improvements
➡ Redis and memcached (And Apache Geode)
➡ mod_socache / mod_slotmem
➡ Data object/blog storage mechanisms
@jimjag

New Modules
➡ mod_proxy submodules:
➡ mod_proxy_fcgi
➡ mod_proxy_scgi
➡ mod_proxy_wstunnel
➡ mod_proxy_html
➡ mod_proxy_express
@jimjag

Cloud and Performance
➡ The Cloud is a game changer for web servers
➡ Horizontal scalability is no longer as painful
➡ Concurrency is no longer the sole consideration
➡ ... or maybe even the primary one
➡ What’s important now? Transaction Time! (because it CAN be)
➡ Low latency
➡ Fast req/resp turnover
➡ Does density still matter? Of course!
➡ micro-services
➡ Are there environs where super-mega concurrency is the
bugaboo? You betcha! (but the cloud makes these more and more rare,
and you’re likely using a bad architecture anyway)
@jimjag

Cloud and Dynamics
➡ The Cloud is a game changer for web servers
➡ The cloud is a dynamic place
➡ automated reconfiguration
➡ horizontal, not vertical scaling
➡ self-aware environments
@jimjag
OK, maybe not THAT self-aware

Why Dynamic Proxy Matters
➡ Apache httpd still the most frequently used front-end
➡ Proxy capabilities must be cloud friendly
➡ Front-end must be dynamic friendly
@jimjag

Apache httpd 2.4 proxy
➡ Reverse Proxy Improvements
➡ Supports FastCGI, SCGI, Websockets in balancer
➡ Additional load balancing mechanisms
➡ Runtime changing of clusters w/o restarts
➡ Support for dynamic configuration
➡ mod_proxy_express
➡ mod_fcgid and fcgistarter
➡ Support for Unix Domain Sockets
@jimjag

Backend Status
➡ Dynamic Health Checks !
➡ TCP/IP Ping
➡ OPTIONS
➡ HEAD
➡ GET
@jimjag
ProxyHCExpr ok234 {%{REQUEST_STATUS} =~ /^[234]/}
ProxyHCExpr gdown {%{REQUEST_STATUS} =~ /^[5]/}
ProxyHCExpr in_maint {hc('body') !~ /Under maintenance/}
<Proxy balancer://foo/>
BalancerMember http://www.example.com/ hcmethod=GET hcexpr=in_maint hcuri=/status.php
BalancerMember http://www2.example.com/ hcmethod=HEAD hcexpr=ok234 hcinterval=10
BalancerMember http://www3.example.com/ hcmethod=TCP hcinterval=5 hcpasses=2 hcfails=3
BalancerMember http://www4.example.com/
</Proxy>
ProxyPass "/" “balancer://foo/"
ProxyPassReverse "/" “balancer://foo/"

Mass Reverse Proxy
➡ Use the new mod_proxy_express module
➡ ProxyPass mapping obtained via db file
➡ Fast and efficient
➡ Still dynamic, with no config changes required
➡ micro-services? You betcha!
@jimjag
ProxyExpress map file
## 
##express-map.db: 
## 
 
www1.example.com http://192.168.002.2:8080 
www2.example.com http://192.168.002.12:8088 
www3.example.com http://192.168.002.10
...
www6341.example.com http://192.168.211.26
httpd.conf file
ProxyExpressEnable On
ProxyExpressDBMFile express-map.db

Embedded Admin
➡ Allows for real-time
➡ Addition of new workers/nodes
➡ Change of LB methods
➡ Can be persistent!
➡ More RESTful
➡ Can be CLI-driven
@jimjag

Easy setup
<Location /balancer-manager>
SetHandler balancer-manager
Require 192.168.2.22
</Location>
@jimjag

server-status aware

Performance
➡ From Nic Rosenthal Battle of the stacks 
(http://www.slideshare.net/AllThingsOpen/battle-of-the-stacks)
@jimjag
HHVM + NGINX!
!
vs!
!
HHVM + Apache 2.4!
!
http://ldr.io/1ogvD7X
http://ldr.io/1ogD7b3
Response time: 76ms
Response time: 60ms
HHVM + NGINX
HHVM + Apache 2.4
Image by Articularnos.com https://www.ﬂickr.com/photos/articularnos/
Champion of the !
Battle Of The Stacks
ATO Edition
HHVM + Apache 2.4

Performance
➡ From Bryan Call’s 2014 ApacheCon preso 
(http://www.slideshare.net/bryan_call/choosing-a-proxy-server-apachecon-2014)
@jimjag
•  Squid&used&the&most&
CPU&again&
•  NGiNX&had&latency&
issues&
•  ATS&most&throughput& 0&
500&
1000&
1500&
2000&
2500&
ATS& NGiNX& Squid& Varnish& hBpd&
RPS$/$CPU$Usage$
0&
5000&
10000&
15000&
20000&
25000&
30000&
Requests$Per$Second$
0&
5&
10&
15&
20&
25&
30&
35&
40&
Latency$
Median&
95th&

Raw Performance
➡ Event MPM : no longer experimental
➡ non-blocking
➡ async
➡ Faster, more efficient APR
➡ Smaller memory footprint
➡ More efficient data structures (worker and event)
@jimjag

Apache httpd vs nginx
➡ Why nginx? Everyone asks about it...
➡ Benchmark: local and reverse proxy transaction times
➡ Apache httpd 2.4.22-dev, nginx 1.8.1
➡ CentOS6, Dual Xeon 3.33GHz
➡ 4GB memory
➡ localhost loopback and external (no firewall)
➡ Double checked results: OSX 10.11.2 (8-core), Fedora 23 (4-
core)
@jimjag

Setup
loopbackSetup 1:
Setup 2:
Setup 3:
Setup 3:

Considerations
➡ Multiple benchmarking systems:
➡ flood (50/250/5/2, 50/100/5/2, 50/5/5/2)
➡ httperf (num-conns=100->20000, numcalls=3,10,100)
➡ weighttp
➡ Full URL requests (www.example.com/index.html)
➡ Static local requests
➡ Static reverse proxy requests
➡ All Apache httpd MPMs
➡ No significant “tuning” efforts (mostly out of the box
configs)
@jimjag

nginx vs Event (typical)
Apache - Event MPM
0
500
1000
1500
2000
nginx
0
500
1,000
1,500
2,000
Open Write Read Close
Increasing concurrency Increasing concurrency

Apache - Prefork MPM
0
500
1000
1500
2000
nginx vs Prefork (typical)
nginx
0
500
1,000
1,500
2,000
Open Write Read Close
Increasing concurrency Increasing concurrency

Total req/resp time
Comparison - total transaction (close)
0
500
1000
1500
2000
Prefork Worker Event nginx
Increasing concurrency

Resp to Req. Bursts - httperf
100 ---> 20000
0.00
1.75
3.50
5.25
7.00
min avg max dev min avg max dev min avg max dev min avg max dev min avg max dev min avg max dev
prefork worker event nginx
Increasing concurrency

Independent benchmarks
Source: Ryosuke Matsumoto : http://blog.matsumoto-r.jp/?p=1812
#!/bin/sh
RESULT='./result.txt'

for port in 80 8080 8888
do
#for count in 1000 2000 3000 4000 5000 6000 7000 8000
9000 10000
#for count in 11000 12000 13000 14000 15000 16000 17000
18000 19000 20000
for count in 21000 22000 23000 24000 25000 26000 27000
28000 29000 30000
do
echo -n "$port $count " >> $RESULT
httperf --rate $count --num-conns 25000 --server
ipaddr --port $port
--uri=/test.html | grep "Request rate:" >>
$RESULT.$port
sleep 60
done
done

Take-away
➡ Today, the web-server isn’t the slow link in the chain.
➡ Benchmarks get stale… fast!
➡ Real world trumps test environs
➡ Choose the right tool for the right job
@jimjag

HTTP/2
➡ Implements RFC 7540
➡ Supports both h2 (HTTP/2 over TLS) and h2c (HTTP/2 over TCP[cleartext])
➡ “Semi-experimental”
➡ Only in that API is still subject to change
➡ Enterprise-ready regarding stability, performance, etc.
➡ USE IT!
➡ Also supported in mod_proxy
@jimjag

What’s next?
➡ TCP Proxy
➡ Better async support
➡ More MPMs
➡ motorz:
➡ Streamlined event driven MPM
➡ Prelim benchmarks: 10% faster, 70% the size
➡ Strict HTTP compliance
➡ mod_brotli (expected in 2.4.26)
➡ PROXY Protocol support (HAProxy)
➡ You tell us!
@jimjag

Thanks
Twitter: @jimjag
Emails: 
jim@jaguNET.com 
jim@apache.org 
jim.jagielski@capitalone.com
http://www.slideshare.net/jimjag/

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