Fragmented arg will do fetch at every encode time, each fetch may get
different result if SMP_F_MAY_CHANGE, for example res.payload, but
the length already encoded in first fragment of the frame, that will
cause SPOA decode failed and waste resources.
This patch must be backported to 1.9 and 1.8.
During 1.9 development (and even a bit after) we've started to face a
significant number of situations where streams were abusively spinning
due to an uncaught error flag or complex conditions that couldn't be
correctly identified. Sometimes streams wake appctx up and conversely
as well. More importantly when this happens the only fix is to restart.
This patch adds a new function to report a serious error, some relevant
info and to crash the process using abort() so that a core dump is
available. The purpose will be for this function to be called in various
situations where the process is unfixable. It will help detect these
issues much earlier during development and may even help fixing test
platforms which are able to automatically restart when such a condition
happens, though this is not the primary purpose.
This patch only provides the function and doesn't use it yet.
We have various functions like conn_get_ctrl_name() to retrieve
some information reported in "show sess" for debugging, which
assume that the connection is valid. This is really not convenient
in code aimed at debugging and is error-prone. Let's add a validity
test first.
Instead of having to manually turn task profiling on/off in the
configuration, by default it will work in "auto" mode, which
automatically turns on on any thread experiencing sustained loop
latencies over one millisecond averaged over the last 1024 samples.
This may happen with configs using lots of regex (thing map_reg for
example, which is the lazy way to convert Apache's rewrite rules but
must not be abused), and such high latencies affect all the process
and the problem is most often intermittent (e.g. hitting a map which
is only used for certain host names).
Thus now by default, with profiling set to "auto", it remains off all
the time until something bad happens. This also helps better focus on
the issues when looking at the logs as well as in "show sess" output.
It automatically turns off when the average loop latency over the last
1024 calls goes below 990 microseconds (which typically takes a while
when in idle).
This patch could be backported to stable versions after a bit more
exposure, as it definitely improves observability and the ability to
quickly spot the culprit. In this case, previous patch ("MINOR:
activity: make the profiling status per thread and not global") must
also be taken.
In order to later support automatic profiling turn on/off, we need to
have it per-thread. We're keeping the global option to know whether to
turn it or on off, but the profiling status is now set per thread. We're
updating the status in activity_count_runtime() which is called before
entering poll(). The reason is that we'll extend this with run time
measurement when deciding to automatically turn it on or off.
Very similarly to previous commit doing the same for streams, we now
measure and report an appctx's call rate. This will help catch applets
which do not consume all their data and/or which do not properly report
that they're waiting for something else. Some of them like peers might
theorically be able to exhibit some occasional peeks when teaching a
full table to a nearby peer (e.g. the new replacement process), but
nothing close to what a bogus service can do so there is no risk of
confusion.
Since the commit 1d2b586cd ("MAJOR: htx: Enable the HTX mode by default for all
proxies"), the HTX is enabled by default for all proxies, HTTP and TCP, but also
CLI and HEALTH proxies. But when the best mux is retrieved, only HTTP and TCP
modes are checked. If the TCP mode is not explicitly set, it is considered as an
HTTP proxy. It is an hidden bug introduced when the option "http-use-htx" was
added. It has no effect until the commit 1d2b586cd. But now, when a stats socket
is created for the master process, the mux h1 is installed on all incoming
connections to the CLI proxy, leading to segfaults because HTX operations are
performed on raw buffers.
So to fix the buf, when a mux is installed, all proxies are considered as TCP
proxies, except HTTP ones. This way, CLI and HEALTH proxies will be handled as
TCP proxies.
This patch must be backported to 1.9 although it has no effect. It is safer to
not keep hidden bugs.
The 'do-resolve' action is an http-request or tcp-request content action
which allows to run DNS resolution at run time in HAProxy.
The name to be resolved can be picked up in the request sent by the
client and the result of the resolution is stored in a variable.
The time the resolution is being performed, the request is on pause.
If the resolution can't provide a suitable result, then the variable
will be empty. It's up to the admin to take decisions based on this
statement (return 503 to prevent loops).
Read carefully the documentation concerning this feature, to ensure your
setup is secure and safe to be used in production.
This patch creates a global counter to track various errors reported by
the action 'do-resolve'.
As by default we add all keepalive connections to the idle pool, if we run
into a pathological case, where all client don't do keepalive, but the server
does, and haproxy is configured to only reuse "safe" connections, we will
soon find ourself having lots of idling, unusable for new sessions, connections,
while we won't have any file descriptors available to create new connections.
To fix this, add 2 new global settings, "pool_low_ratio" and "pool_high_ratio".
pool-low-fd-ratio is the % of fds we're allowed to use (against the maximum
number of fds available to haproxy) before we stop adding connections to the
idle pool, and destroy them instead. The default is 20. pool-high-fd-ratio is
the % of fds we're allowed to use (against the maximum number of fds available
to haproxy) before we start killing idling connection in the event we have to
create a new outgoing connection, and no reuse is possible. The default is 25.
For most of the xprt methods, provide a xprt_ctx. This will be useful later
when we'll want to be able to stack xprts.
The init() method now has to create and provide the said xprt_ctx if needed.
task_delete() was never used without calling task_free() just after, and
task_free() was only used on error pathes to destroy a just-created task,
so merge them into task_destroy(), that will remove the task from the
wait queue, and make sure the task is either destroyed immediately if it's
not in the run queue, or destroyed when it's supposed to run.
The wakeup condition in task_wakeup() is redundant as it is already
validated by the CAS. Better move the __task_wakeup() call there, it
also has the merit of being easier to audit this way. This also reduces
the code size by around 1.8 kB :
$ size haproxy-?
text data bss dec hex filename
2153806 100208 1307676 3561690 3658da haproxy-1
2152094 100208 1307676 3559978 36522a haproxy-2
Commit 0c7a4b6 ("MINOR: tasks: Don't set the TASK_RUNNING flag when
adding in the tasklet list.") revealed a hole in the way tasks may
be freed : they could be removed while in the run queue when the
TASK_QUEUED flag was present but not the TASK_RUNNING one. But it
seems the issue was emphasized by commit cde7902 ("MEDIUM: tasks:
improve fairness between the local and global queues") though the
code it replaces was already affected given how late the TASK_RUNNING
flag was set after removal from the global queue.
At the moment the task is picked from the global run queue, if it
is the last one, the global run queue lock is dropped, and then
the TASK_RUNNING flag was added. In the mean time another thread
might have performed a task_free(), and immediately after, the
TASK_RUNNING flag was re-added to the task, which was then added
to the tasklet list. The unprotected window was extremely faint
but does definitely exist and inconsistent task lists have been
observed a few times during very intensive tests over the last few
days. From this point various options are possible, the task might
have been re-allocated while running, and assigned state 0 and/or
state QUEUED while it was still running, resulting in the tast not
being put back into the tree.
This commit simply makes sure that tests on TASK_RUNNING before removing
the task also cover TASK_QUEUED.
It must be backported to 1.9 along with the previous ones touching
that area.
Now that we have the warranty that a task won't be added in the runqueue
while the TASK_QUEUED or the TASK_RUNNING flag is set, don't bother trying
to lock the task by setting leaf_p to 0x1 while inserting it in the runqueue
or having it in the tasklet_list, as nobody else will attempt to add it.
Make sure we set TASK_QUEUED in every case before adding the task to the
run queue. task_wakeup() now checks if either TASK_QUEUED or TASK_RUNNING
is set, and if neither is set, add TASK_QUEUED and effectively add the task
to the runqueue.
No longer use __task_wakeup() anywhere except in task_wakeup(), always use
task_wakeup() instead.
With the old code, process_runnable_task() may re-add a task in the runqueue
without setting the TASK_QUEUED flag, and there were race conditions that could
lead to a task having the TASK_QUEUED flag but not in the runqueue, thus
being unschedulable.
This should be backported to 1.9.
As for smp_prefetch_http(), there is now a way to successfully perform a
prefetch in HTX, even if the message forwarding already begun. It is used for
the sample fetches "req.proto_http" and "method".
This patch must be backported to 1.9.
All HTTP samples are buggy because the channel tested in the prefetch functions
(HTX and legacy HTTP) is chosen depending on the sample direction and not the
keyword really used. It means the request channel is used if the sample is
called during the request analysis and the response channel is used if it is
called during the response analysis, regardless the sample really called. For
instance, if you use the sample "req.ver" in an http-response rule, the response
channel will be prefeched because it is called during the response analysis,
while the request channel should have been used instead. So some assumptions on
the validity of the sample may be made on the wrong channel. It is the first
bug.
Then the same error is done in some samples themselves. So fetches are performed
on the wrong channel. For instance, the header extraction (req.fhdr, res.fhdr,
req.hdr, res.hdr...). If the sample "req.hdr" is used in an http-response rule,
then the matching is done on the response headers and not the request ones. It
is the second bug.
Finally, the last one but not the least, in some samples, the right channel is
used. But because the prefetch was done on the wrong one, this channel may be in
a undefined state. For instance, using the sample "req.ver" in an http-response
rule leads to a matching on a posibility released buffer.
To fix all these bugs, the right channel is now chosen in sample fetches, before
the prefetch. If the same function is used to fetch requests and responses
elements, then the keyword is used to choose the right one. This channel is then
used by the functions smp_prefetch_htx() and smp_prefetch_http(). Of course, it
is also used by the samples themselves to extract information.
This patch must be backported to all supported versions. For version 1.8 and
priors, it must be totally refactored. First because there is no HTX into these
versions. Then the buffers API has changed in HAProxy 1.9. The files
http_fetch.{ch} doesn't exist on old versions.
Maksim Kupriianov reported very strange crashes in fwrr_update_position()
which didn't make sense because of an apparent divide overflow except that
the value was not null in the core.
It happens that while the locking is correct in all the functions' call
graph, the uppermost one (fwrr_get_next_server()) incorrectly expected
that its target server was already locked when called. This stupid
assumption causd the server lock not to be held when calling the other
ones, explaining how it was possible to change the server's eweight by
calling srv_lb_commit_status() under the server lock yet collide with
its unprotected usage.
This commit makes sure that fwrr_get_server_from_group() retrieves a
locked server and that fwrr_get_next_server() is responsible for
unlocking the server before returning it. There is one subtlety in
this function which is that it builds a list of avoided servers that
were full while scanning the tree, and all of them are queued in a
full state so they must be unlocked upon return.
Many thanks to Maksim for providing detailed info allowing to narrow
down this bug.
This fix must be backported to 1.9. In 1.8 the lock seems much wider
and changes to the server's state are performed under the rendez-vous
point so this it doesn't seem possible that it happens there.
Older compilers don't like to see "inline" placed after the type in a
function declaration, it must be "static inline <type>" only. This
patch touches various areas. The warnings were seen with gcc-3.4.
This one hasn't been used anymore since the scheduler changes after 1.8
but it kept being exported and maintained up to date while it's always
reset when scanning the trees. Let's stop exporting it and updating it.
This function will handle mux upgrades, for frontend connections only. It will
retrieve the best mux in the same way than conn_install_mux_fe except that the
mode and optionnally the proto are forced.
The new multiplexer is initialized using a new context and a specific input
buffer. Then, the old one is destroyed. If an error occurred, everything is
rolled back.
It is mandatory to handle mux upgrades, because during a mux upgrade, the
connection will be reassigned to another multiplexer. So when the old one is
destroyed, it does not own the connection anymore. Or in other words, conn->ctx
does not point to the old mux's context when its destroy() callback is
called. So we now rely on the multiplexer context do destroy it instead of the
connection.
In addition, h1_release() and h2_release() have also been updated in the same
way.
The mux's callback init() now take a pointer to a buffer as extra argument. It
must be used by the multiplexer as its input buffer. This buffer is always NULL
when a multiplexer is initialized with a fresh connection. But if a mux upgrade
is performed, it may be filled with existing data. Note that, for now, mux
upgrades are not supported. But this commit is mandatory to do so.
Because the option http-tunnel is now ignored in HTX, there is no longer any
need to adjust the transaction mode in HTX analyzers. A channel can still be
switch to the tunnel mode for legitimate cases (HTTP CONNECT or switching
protocols). So the function htx_adjust_conn_mode() is now useless.
This patch must be backported to 1.9. It is not strictly speaking required but
it will ease futur backports.
This patch implements the external binary support in the master worker.
To configure an external process, you need to use the program section,
for example:
program dataplane-api
command ./dataplane_api
Those processes are launched at the same time as the workers.
During a reload of HAProxy, those processes are dealing with the same
sequence as a worker:
- the master is re-executed
- the master sends a USR1 signal to the program
- the master launches a new instance of the program
During a stop, or restart, a SIGTERM is sent to the program.
The children variable is still used in haproxy, it is not required
anymore since we have the information about the current workers in the
mworker_proc linked list.
The oldpids array is also replaced by this linked list when we
generated the arguments for the master reexec.
I found on an (old) AIX 5.1 machine that stdint.h didn't exist while
inttypes.h which is expected to include it does exist and provides the
desired functionalities.
As explained here, stdint being just a subset of inttypes for use in
freestanding environments, it's probably always OK to switch to inttypes
instead:
https://pubs.opengroup.org/onlinepubs/009696799/basedefs/stdint.h.html
Also it's even clearer here in the autoconf doc :
https://www.gnu.org/software/autoconf/manual/autoconf-2.61/html_node/Header-Portability.html
"The C99 standard says that inttypes.h includes stdint.h, so there's
no need to include stdint.h separately in a standard environment.
Some implementations have inttypes.h but not stdint.h (e.g., Solaris
7), but we don't know of any implementation that has stdint.h but not
inttypes.h"
Previous commit 3ea351368 ("BUG/MEDIUM: h2: Remove the tasklet from the
task list if unsubscribing.") uncovered an issue which needs to be
addressed in the scheduler's API. The function task_remove_from_task_list()
was initially designed to remove a task from the running tasklet list from
within the scheduler, and had to be used in h2 to abort pending I/O events.
However this function was not designed to be idempotent, occasionally
causing a double removal from the tasklet list, with the second doing
nothing but affecting the apparent tasks count and making haproxy use
100% CPU on some tests consisting in stopping the client during some
transfers. The h2_unsubscribe() function can sometimes be called upon
stream exit after an error where the tasklet was possibly already
removed, so it.
This patch does 2 things :
- it renames task_remove_from_task_list() to
__task_remove_from_tasklet_list() to discourage users from calling
it. Also note the fix in the naming since it's a tasklet list and
not a task list. This function is still uesd from the scheduler.
- it adds a new, idempotent, task_remove_from_tasklet_list() function
which does nothing if the task is already not in the tasklet list.
This patch will need to be backported where the commit above is backported.
It's never easy to guess what services are built in. We currently have
the prometheus exporter in contrib/ which is the only extension for now.
Let's enumerate all available ones just like we do for filterr and pollers.
The status codes definition (STAT_STATUS_*) and their string representation
stat_status_codes) have been moved in stats files. There is no reason to keep
them in proto_http files.
In task_unlink_rq, to decide if we should logk the global runqueue lock,
use the TASK_GLOBAL flag instead of relying on t->thread_mask being tid_bit,
as it could be so while still being in the global runqueue if another thread
woke that task for us.
This should be backported to 1.9.
