If we want to be able to match ACLs against a lot of possible values, we
need to put those values in trees. That will only work for exact matches,
which is normally just what is needed.
Right now, only IPv4 and string matching are planned, but others might come
later.
This is used to disable persistence depending on some conditions (for
example using an ACL matching static files or a specific User-Agent).
You can see it as a complement to "force-persist".
In the configuration file, the force-persist/ignore-persist declaration
order define the rules priority.
Used with the "appsesion" keyword, it can also help reducing memory usage,
as the session won't be hashed the persistence is ignored.
Some servers do not completely conform with RFC2616 requirements for
keep-alive when they receive a request with "Connection: close". More
specifically, they don't bother using chunked encoding, so the client
never knows whether the response is complete or not. One immediately
visible effect is that haproxy cannot maintain client connections alive.
The second issue is that truncated responses may be cached on clients
in case of network error or timeout.
Óscar Frías Barranco reported this issue on Tomcat 6.0.20, and
Patrik Nilsson with Jetty 6.1.21.
Cyril Bonté proposed this smart idea of pretending we run keep-alive
with the server and closing it at the last moment as is already done
with option forceclose. The advantage is that we only change one
emitted header but not the overall behaviour.
Since some servers such as nginx are able to close the connection
very quickly and save network packets when they're aware of the
close negociation in advance, we don't enable this behaviour by
default.
"option http-pretend-keepalive" will have to be used for that, in
conjunction with "option http-server-close".
Using get_ip_from_hdr2() we can look for occurrence #X or #-X and
extract the IP it contains. This is typically designed for use with
the X-Forwarded-For header.
Using "usesrc hdr_ip(name,occ)", it becomes possible to use the IP address
found in <name>, and possibly specify occurrence number <occ>, as the
source to connect to a server. This is possible both in a server and in
a backend's source statement. This is typically used to use the source
IP previously set by a upstream proxy.
The transparent proxy address selection was set in the TCP connect function
which is not the most appropriate place since this function has limited
access to the amount of parameters which could produce a source address.
Instead, now we determine the source address in backend.c:connect_server(),
right after calling assign_server_address() and we assign this address in
the session and pass it to the TCP connect function. This cannot be performed
in assign_server_address() itself because in some cases (transparent mode,
dispatch mode or http_proxy mode), we assign the address somewhere else.
This change will open the ability to bind to addresses extracted from many
other criteria (eg: from a header).
We'll need another flag in the 'options' member close to PR_O_TPXY_*,
and all are used, so let's move this easy one to options2 (which are
already used for SQL checks).
The following patch fixed an issue but brought another one :
296897 [MEDIUM] connect to servers even when the input has already been closed
The new issue is that when a connection is inspected and aborted using
TCP inspect rules, now it is sent to the server before being closed. So
that test is not satisfying. A probably better way is not to prevent a
connection from establishing if only BF_SHUTW_NOW is set but BF_SHUTW
is not. That way, the BF_SHUTW flag is not set if the request has any
data pending, which still fixes the stats issue, but does not let any
empty connection pass through.
Also, as a safety measure, we extend buffer_abort() to automatically
disable the BF_AUTO_CONNECT flag. While it appears to always be OK,
it is by pure luck, so better safe than sorry.
We are seeing both real servers repeatedly going on- and off-line with
a period of tens of seconds. Packet tracing, stracing, and adding
debug code to HAProxy itself has revealed that the real servers are
always responding correctly, but HAProxy is sometimes receiving only
part of the response.
It appears that the real servers are sending the test page as three
separate packets. HAProxy receives the contents of one, two, or three
packets, apparently randomly. Naturally, the health check only
succeeds when all three packets' data are seen by HAProxy. If HAProxy
and the real servers are modified to use a plain HTML page for the
health check, the response is in the form of a single packet and the
checks do not fail.
(...)
I've added buffer and length variables to struct server, and allocated
space with the rest of the server initialisation.
(...)
It seems to be working fine in my tests, and handles check responses
that are bigger than the buffer.
today I've noticed that the stats page still displays v1.3 in the
"Updates" link, due to the PRODUCT_BRANCH value in version.h, then
it's maybe time to send you the result (notice that the patch updates
PRODUCT_BRANCH to "1.4").
--
Cyril Bonté
When trying to spot some complex bugs, it's often needed to access
information on stuck sessions, which is quite difficult. This new
command helps one get detailed information about a session, with
flags, timers, states, etc... The buffer data are not dumped yet.
Often we need to understand why some transfers were aborted or what
constitutes server response errors. With those two counters, it is
now possible to detect an unexpected transfer abort during a data
phase (eg: too short HTTP response), and to know what part of the
server response errors may in fact be assigned to aborted transfers.
The bounce realign function was algorithmically good but as expected
it was not cache-friendly. Using it with large requests caused so many
cache thrashing that the function itself could drain 70% of the total
CPU time for only 0.5% of the calls !
Revert back to a standard memcpy() using a specially allocated swap
buffer. We're now back to 2M req/s on pipelined requests.
It is wrong to merge FE and BE stats for a proxy because when we consult a
BE's stats, it reflects the FE's stats eventhough the BE has received no
traffic. The most common example happens with listen instances, where the
backend gets credited for all the trafic even when a use_backend rule makes
use of another backend.
The trash buffer may now be smaller than a buffer because we can tune
it at run time. This causes a risk when we're trying to use it as a
temporary buffer to realign unaligned requests, because we may have to
put up to a full buffer into it.
Instead of doing a double copy, we're now relying on an open-coded
bouncing copy algorithm. The principle is that we move one byte at
a time to its final place, and if that place also holds a byte, then
we move it too, and so on. We finish when we've moved all the buffer.
It limits the number of memory accesses, but since it proceeds one
byte at a time and with random walk, it's not cache friendly and
should be slower than a double copy. However, it's only used in
extreme situations and the difference will not be noticeable.
It has been extensively tested and works reliably.
This is a first attempt to add a maintenance mode on servers, using
the stat socket (in admin level).
It can be done with the following command :
- disable server <backend>/<server>
- enable server <backend>/<server>
In this mode, no more checks will be performed on the server and it
will be marked as a special DOWN state (MAINT).
If some servers were tracking it, they'll go DOWN until the server
leaves the maintenance mode. The stats page and the CSV export also
display this special state.
This can be used to disable the server in haproxy before doing some
operations on this server itself. This is a good complement to the
"http-check disable-on-404" keyword and works in TCP mode.
Support the new syntax (http-request allow/deny/auth) in
http stats.
Now it is possible to use the same syntax is the same like in
the frontend/backend http-request access control:
acl src_nagios src 192.168.66.66
acl stats_auth_ok http_auth(L1)
stats http-request allow if src_nagios
stats http-request allow if stats_auth_ok
stats http-request auth realm LB
The old syntax is still supported, but now it is emulated
via private acls and an aditional userlist.
Add generic authentication & authorization support.
Groups are implemented as bitmaps so the count is limited to
sizeof(int)*8 == 32.
Encrypted passwords are supported with libcrypt and crypt(3), so it is
possible to use any method supported by your system. For example modern
Linux/glibc instalations support MD5/SHA-256/SHA-512 and of course classic,
DES-based encryption.
Implement Base64 decoding with a reverse table.
The function accepts and decodes classic base64 strings, which
can be composed from many streams as long each one is properly
padded, for example: SGVsbG8=IEhBUHJveHk=IQ==
Just as for the req* rules, we can now condition rsp* rules with ACLs.
ACLs match on response, so volatile request information cannot be used.
A warning is emitted if a configuration contains such an anomaly.
From now on, if request filters have ACLs defined, these ACLs will be
evaluated to condition the filter. This will be used to conditionally
remove/rewrite headers based on ACLs.
This function automatically builds a rule, considering the if/unless
statements, and automatically updates the proxy's acl_requires, the
condition's file and line.
Now a server can check the contents of the header X-Haproxy-Server-State
to know how haproxy sees it. The same values as those reported in the stats
are provided :
- up/down status + check counts
- throttle
- weight vs backend weight
- active sessions vs backend sessions
- queue length
- haproxy node name
Currently we cannot easily add headers nor anything to HTTP checks
because the requests are pre-formatted with the last CRLF. Make the
check code add the CRLF itself so that we can later add useful info.
Some converters will need one or several arguments. It's not possible
to write a simple generic parser for that, so let's add the ability
for each converter to support its own argument parser, and call it
to get the arguments when it's specified. If unspecified, the arguments
are passed unmodified as string+len.
The pattern type converters currently support a string arg and a length.
Sometimes we'll prefer to pass them a list or a structure. So let's convert
the string and length into a generic void* and int that each converter may
use as it likes.
Despite what is explicitly stated in HTTP specifications,
browsers still use the undocumented Proxy-Connection header
instead of the Connection header when they connect through
a proxy. As such, proxies generally implement support for
this stupid header name, breaking the standards and making
it harder to support keep-alive between clients and proxies.
Thus, we add a new "option http-use-proxy-header" to tell
haproxy that if it sees requests which look like proxy
requests, it should use the Proxy-Connection header instead
of the Connection header.
This is used to force access to down servers for some requests. This
is useful when validating that a change on a server correctly works
before enabling the server again.
Sometimes we need to be able to change the default kernel socket
buffer size (recv and send). Four new global settings have been
added for this :
- tune.rcvbuf.client
- tune.rcvbuf.server
- tune.sndbuf.client
- tune.sndbuf.server
Those can be used to reduce kernel memory footprint with large numbers
of concurrent connections, and to reduce risks of write timeouts with
very slow clients due to excessive kernel buffering.
We need to improve Connection header handling in the request for it
to support the upcoming keep-alive mode. Now we have two flags which
keep in the session the information about the presence of a
Connection: close and a Connection: keep-alive headers in the initial
request, as well as two others which keep the current state of those
headers so that we don't have to parse them again. Knowing the initial
value is essential to know when the client asked for keep-alive while
we're forcing a close (eg in server-close mode). Also the Connection
request parser is now able to automatically remove single header values
at the same time they are parsed. This provides greater flexibility and
reliability.
All combinations of listen/front/back in all modes and with both
1.0 and 1.1 have been tested.
Some header values might be delimited with spaces, so it's not enough to
compare "close" or "keep-alive" with strncasecmp(). Use word_match() for
that.
Calling this function after http_find_header2() automatically deletes
the current value of the header, and removes the header itself if the
value is the only one. The context is automatically adjusted for a
next call to http_find_header2() to return the next header. No other
change nor test should be made on the transient context though.
