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HAProxy how-to

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version 1.9

willy tarreau

2018/09/12

1) How to build it

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This is a development version, so it is expected to break from time to time,

to add and remove features without prior notification and it should not be used

in production. If you are not used to build from sources or if you are not used

to follow updates then it is recommended that instead you use the packages provided

by your software vendor or Linux distribution. Most of them are taking this task

seriously and are doing a good job at backporting important fixes. If for any

reason you'd prefer a different version than the one packaged for your system,

you want to be certain to have all the fixes or to get some commercial support,

other choices are available at :

http://www.haproxy.com/

To build haproxy, you will need :

- GNU make. Neither Solaris nor OpenBSD's make work with the GNU Makefile.

If you get many syntax errors when running "make", you may want to retry

with "gmake" which is the name commonly used for GNU make on BSD systems.

- GCC between 2.95 and 4.8. Others may work, but not tested.

- GNU ld

Also, you might want to build with libpcre support, which will provide a very

efficient regex implementation and will also fix some badness on Solaris' one.

To build haproxy, you have to choose your target OS amongst the following ones

and assign it to the TARGET variable :

- linux22 for Linux 2.2

- linux24 for Linux 2.4 and above (default)

- linux24e for Linux 2.4 with support for a working epoll (> 0.21)

- linux26 for Linux 2.6 and above

- linux2628 for Linux 2.6.28, 3.x, and above (enables splice and tproxy)

- solaris for Solaris 8 or 10 (others untested)

- freebsd for FreeBSD 5 to 10 (others untested)

- netbsd for NetBSD

- osx for Mac OS/X

- openbsd for OpenBSD 5.7 and above

- aix51 for AIX 5.1

- aix52 for AIX 5.2

- cygwin for Cygwin

- haiku for Haiku

- generic for any other OS or version.

- custom to manually adjust every setting

You may also choose your CPU to benefit from some optimizations. This is

particularly important on UltraSparc machines. For this, you can assign

one of the following choices to the CPU variable :

- i686 for intel PentiumPro, Pentium 2 and above, AMD Athlon

- i586 for intel Pentium, AMD K6, VIA C3.

- ultrasparc : Sun UltraSparc I/II/III/IV processor

- native : use the build machine's specific processor optimizations. Use with

extreme care, and never in virtualized environments (known to break).

- generic : any other processor or no CPU-specific optimization. (default)

Alternatively, you may just set the CPU_CFLAGS value to the optimal GCC options

for your platform.

You may want to build specific target binaries which do not match your native

compiler's target. This is particularly true on 64-bit systems when you want

to build a 32-bit binary. Use the ARCH variable for this purpose. Right now

it only knows about a few x86 variants (i386,i486,i586,i686,x86_64), two

generic ones (32,64) and sets -m32/-m64 as well as -march=<arch> accordingly.

If your system supports PCRE (Perl Compatible Regular Expressions), then you

really should build with libpcre which is between 2 and 10 times faster than

other libc implementations. Regex are used for header processing (deletion,

rewriting, allow, deny). The only inconvenient of libpcre is that it is not

yet widely spread, so if you build for other systems, you might get into

trouble if they don't have the dynamic library. In this situation, you should

statically link libpcre into haproxy so that it will not be necessary to

install it on target systems. Available build options for PCRE are :

- USE_PCRE=1 to use libpcre, in whatever form is available on your system

(shared or static)

- USE_STATIC_PCRE=1 to use a static version of libpcre even if the dynamic

one is available. This will enhance portability.

- with no option, use your OS libc's standard regex implementation (default).

Warning! group references on Solaris seem broken. Use static-pcre whenever

possible.

If your system doesn't provide PCRE, you are encouraged to download it from

http://www.pcre.org/ and build it yourself, it's fast and easy.

Recent systems can resolve IPv6 host names using getaddrinfo(). This primitive

is not present in all libcs and does not work in all of them either. Support in

glibc was broken before 2.3. Some embedded libs may not properly work either,

thus, support is disabled by default, meaning that some host names which only

resolve as IPv6 addresses will not resolve and configs might emit an error

during parsing. If you know that your OS libc has reliable support for

getaddrinfo(), you can add USE_GETADDRINFO=1 on the make command line to enable

it. This is the recommended option for most Linux distro packagers since it's

working fine on all recent mainstream distros. It is automatically enabled on

Solaris 8 and above, as it's known to work.

It is possible to add native support for SSL using the GNU makefile, by passing

"USE_OPENSSL=1" on the make command line. The libssl and libcrypto will

automatically be linked with haproxy. Some systems also require libz, so if the

build fails due to missing symbols such as deflateInit(), then try again with

"ADDLIB=-lz".

Your are strongly encouraged to always use an up-to-date version of OpenSSL, as

found on https://www.openssl.org/ as vulnerabilities are occasionally found and

you don't want them on your systems. HAProxy is known to build correctly on all

currently supported branches (0.9.8, 1.0.0, 1.0.1, 1.0.2 and 1.1.0 at the time

of writing). Branch 1.0.2 is currently recommended for the best combination of

features and stability. Asynchronous engines require OpenSSL 1.1.0 though. It's

worth mentionning that some OpenSSL derivatives are also reported to work but

may occasionally break. Patches to fix them are welcome but please read the

CONTRIBUTING file first.

To link OpenSSL statically against haproxy, build OpenSSL with the no-shared

keyword and install it to a local directory, so your system is not affected :

$ export STATICLIBSSL=/tmp/staticlibssl

$ ./config --prefix=$STATICLIBSSL no-shared

$ make && make install_sw

When building haproxy, pass that path via SSL_INC and SSL_LIB to make and

include additional libs with ADDLIB if needed (in this case for example libdl):

$ make TARGET=linux26 USE_OPENSSL=1 SSL_INC=$STATICLIBSSL/include SSL_LIB=$STATICLIBSSL/lib ADDLIB=-ldl

It is also possible to include native support for zlib to benefit from HTTP

compression. For this, pass "USE_ZLIB=1" on the "make" command line and ensure

that zlib is present on the system. Alternatively it is possible to use libslz

for a faster, memory less, but slightly less efficient compression, by passing

"USE_SLZ=1".

Zlib is commonly found on most systems, otherwise updates can be retrieved from

http://www.zlib.net/. It is easy and fast to build. Libslz can be downloaded

from http://1wt.eu/projects/libslz/ and is even easier to build.

By default, the DEBUG variable is set to '-g' to enable debug symbols. It is

not wise to disable it on uncommon systems, because it's often the only way to

get a complete core when you need one. Otherwise, you can set DEBUG to '-s' to

strip the binary.

For example, I use this to build for Solaris 8 :

$ make TARGET=solaris CPU=ultrasparc USE_STATIC_PCRE=1

And I build it this way on OpenBSD or FreeBSD :

$ gmake TARGET=freebsd USE_PCRE=1 USE_OPENSSL=1 USE_ZLIB=1

And on a classic Linux with SSL and ZLIB support (eg: Red Hat 5.x) :

$ make TARGET=linux26 USE_PCRE=1 USE_OPENSSL=1 USE_ZLIB=1

And on a recent Linux >= 2.6.28 with SSL and ZLIB support :

$ make TARGET=linux2628 USE_PCRE=1 USE_OPENSSL=1 USE_ZLIB=1

In order to build a 32-bit binary on an x86_64 Linux system with SSL support

without support for compression but when OpenSSL requires ZLIB anyway :

$ make TARGET=linux26 ARCH=i386 USE_OPENSSL=1 ADDLIB=-lz

The SSL stack supports session cache synchronization between all running

processes. This involves some atomic operations and synchronization operations

which come in multiple flavors depending on the system and architecture :

Atomic operations :

- internal assembler versions for x86/x86_64 architectures

- gcc builtins for other architectures. Some architectures might not

be fully supported or might require a more recent version of gcc.

If your architecture is not supported, you willy have to either use

pthread if supported, or to disable the shared cache.

- pthread (posix threads). Pthreads are very common but inter-process

support is not that common, and some older operating systems did not

report an error when enabling multi-process mode, so they used to

silently fail, possibly causing crashes. Linux's implementation is

fine. OpenBSD doesn't support them and doesn't build. FreeBSD 9 builds

and reports an error at runtime, while certain older versions might

silently fail. Pthreads are enabled using USE_PTHREAD_PSHARED=1.

Synchronization operations :

- internal spinlock : this mode is OS-independant, light but will not

scale well to many processes. However, accesses to the session cache

are rare enough that this mode could certainly always be used. This

is the default mode.

- Futexes, which are Linux-specific highly scalable light weight mutexes

implemented in user-space with some limited assistance from the kernel.

This is the default on Linux 2.6 and above and is enabled by passing

USE_FUTEX=1

- pthread (posix threads). See above.

If none of these mechanisms is supported by your platform, you may need to

build with USE_PRIVATE_CACHE=1 to totally disable SSL cache sharing. Then

it is better not to run SSL on multiple processes.

If you need to pass other defines, includes, libraries, etc... then please

check the Makefile to see which ones will be available in your case, and

use the USE_* variables in the Makefile.

AIX 5.3 is known to work with the generic target. However, for the binary to

also run on 5.2 or earlier, you need to build with DEFINE="-D_MSGQSUPPORT",

otherwise __fd_select() will be used while not being present in the libc, but

this is easily addressed using the "aix52" target. If you get build errors

because of strange symbols or section mismatches, simply remove -g from

DEBUG_CFLAGS.

You can easily define your own target with the GNU Makefile. Unknown targets

are processed with no default option except USE_POLL=default. So you can very

well use that property to define your own set of options. USE_POLL can even be

disabled by setting USE_POLL="". For example :

$ gmake TARGET=tiny USE_POLL="" TARGET_CFLAGS=-fomit-frame-pointer

1.1) Device Detection

---------------------

HAProxy supports several device detection modules relying on third party

products. Some of them may provide free code, others free libs, others free

evaluation licenses. Please read about their respective details in the

following files :

doc/DeviceAtlas-device-detection.txt for DeviceAtlas

doc/51Degrees-device-detection.txt for 51Degrees

doc/WURFL-device-detection.txt for Scientiamobile WURFL

2) How to install it

--------------------

To install haproxy, you can either copy the single resulting binary to the

place you want, or run :

$ sudo make install

If you're packaging it for another system, you can specify its root directory

in the usual DESTDIR variable.

3) How to set it up

-------------------

There is some documentation in the doc/ directory :

- intro.txt : this is an introduction to haproxy, it explains what it is

what it is not. Useful for beginners or to re-discover it when planning

for an upgrade.

- architecture.txt : this is the architecture manual. It is quite old and

does not tell about the nice new features, but it's still a good starting

point when you know what you want but don't know how to do it.

- configuration.txt : this is the configuration manual. It recalls a few

essential HTTP basic concepts, and details all the configuration file

syntax (keywords, units). It also describes the log and stats format. It

is normally always up to date. If you see that something is missing from

it, please report it as this is a bug. Please note that this file is

huge and that it's generally more convenient to review Cyril Bonté's

HTML translation online here :

http://cbonte.github.io/haproxy-dconv/configuration-1.6.html

- management.txt : it explains how to start haproxy, how to manage it at

runtime, how to manage it on multiple nodes, how to proceed with seamless

upgrades.

- gpl.txt / lgpl.txt : the copy of the licenses covering the software. See

the 'LICENSE' file at the top for more information.

- the rest is mainly for developers.

There are also a number of nice configuration examples in the "examples"

directory as well as on several sites and articles on the net which are linked

to from the haproxy web site.

4) How to report a bug

----------------------

It is possible that from time to time you'll find a bug. A bug is a case where

what you see is not what is documented. Otherwise it can be a misdesign. If you

find that something is stupidly design, please discuss it on the list (see the

"how to contribute" section below). If you feel like you're proceeding right

and haproxy doesn't obey, then first ask yourself if it is possible that nobody

before you has even encountered this issue. If it's unlikely, the you probably

have an issue in your setup. Just in case of doubt, please consult the mailing

list archives :

http://marc.info/?l=haproxy

Otherwise, please try to gather the maximum amount of information to help

reproduce the issue and send that to the mailing list :

haproxy@formilux.org

Please include your configuration and logs. You can mask your IP addresses and

passwords, we don't need them. But it's essential that you post your config if

you want people to guess what is happening.

Also, keep in mind that haproxy is designed to NEVER CRASH. If you see it die

without any reason, then it definitely is a critical bug that must be reported

and urgently fixed. It has happened a couple of times in the past, essentially

on development versions running on new architectures. If you think your setup

is fairly common, then it is possible that the issue is totally unrelated.

Anyway, if that happens, feel free to contact me directly, as I will give you

instructions on how to collect a usable core file, and will probably ask for

other captures that you'll not want to share with the list.

5) How to contribute

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Please carefully read the CONTRIBUTING file that comes with the sources. It is

mandatory.

-- end