Sadly we didn't have the cumulated number of connections established to
servers till now, so let's now update it per backend and per-server and
report it in the stats. On the stats page it appears in the tooltip
when hovering over the total sessions count field.
In some situations, especially when dealing with low latency on processors
supporting a variable frequency or when running inside virtual machines,
each time the process waits for an I/O using the poller, the processor
goes back to sleep or is offered to another VM for a long time, and it
causes excessively high latencies.
A solution to this provided by this patch is to enable busy polling using
a global option. When busy polling is enabled, the pollers never sleep and
loop over themselves waiting for an I/O event to happen or for a timeout
to occur. On multi-processor machines it can significantly overheat the
processor but it usually results in much lower latencies.
A typical test consisting in injecting traffic over a single connection at
a time over the loopback shows a bump from 4640 to 8540 connections per
second on forwarded connections, indicating a latency reduction of 98
microseconds for each connection, and a bump from 12500 to 21250 for
locally terminated connections (redirects), indicating a reduction of
33 microseconds.
It is only usable with epoll and kqueue because select() and poll()'s
API is not convenient for such usages, and the level of performance they
are used in doesn't benefit from this anyway.
The option, which obviously remains disabled by default, can be turned
on using "busy-polling" in the global section, and turned off later
using "no busy-polling". Its status is reported in "show info" to help
troubleshooting suspicious CPU spikes.
This patch allows a process to properly quit when some jobs are still
active, this feature is handled by the unstoppable_jobs variable, which
must be atomically incremented.
During each new iteration of run_poll_loop() the break condition of the
loop is now (jobs - unstoppable_jobs) == 0.
The unique usage of this at the moment is to handle the socketpair CLI
of a the worker during the stopping of the process. During the soft
stop, we could mark the CLI listener as an unstoppable job and still
handle new connections till every other jobs are stopped.
It's easy to detect when logs on some paths are lost as sendmsg() will
return EAGAIN. This is particularly true when sending to /dev/log, which
often doesn't support a big logging capacity. Let's keep track of these
and report the total number of dropped messages in "show info".
The active peers output indicates both the number of established peers
connections and the number of peers connection attempts. The new counter
"ConnectedPeers" also indicates the number of currently connected peers.
This helps detect that some peers cannot be reached for example. It's
worth mentioning that this value changes over time because unused peers
are often disconnected and reconnected. Most of the time it should be
equal to ActivePeers.
Peers are the last type of activity which can maintain a job present, so
it's important to report that such an entity is still active to explain
why the job count may be higher than zero. Here by "ActivePeers" we report
peers sessions, which include both established connections and outgoing
connection attempts.
When an haproxy process doesn't stop after a reload, it's because it
still has some active "jobs", which mainly are active sessions, listeners,
peers or other specific activities. Sometimes it's difficult to troubleshoot
the cause of these issues (which generally are the result of a bug) only
because some indicators are missing.
This patch add the number of listeners, the number of jobs, and the stopping
status to the output of "show info". This way it becomes a bit easier to try
to narrow down the cause of such an issue should it happen. A typical use
case is to connect to the CLI before reloading, then issuing the "show info"
command to see what happens. In the normal situation, stopping should equal
1, jobs should equal 1 (meaning only the CLI is still active) and listeners
should equal zero.
The patch is so trivial that it could make sense to backport it to 1.8 in
order to help with troubleshooting.
This patch adds a warning if an http-(request|reponse) (add|set)-header
rewrite fails to change the respective header in a request or response.
This usually happens when tune.maxrewrite is not sufficient to hold all
the headers that should be added.
This may be used to output the JSON schema which describes the output of
show info json and show stats json.
The JSON output is without any extra whitespace in order to reduce the
volume of output. For human consumption passing the output through a
pretty printer may be helpful.
e.g.:
$ echo "show schema json" | socat /var/run/haproxy.stat stdio | \
python -m json.tool
The implementation does not generate the schema. Some consideration could
be given to integrating the output of the schema with the output of
typed and json info and stats. In particular the types (u32, s64, etc...)
and tags.
A sample verification of show info json and show stats json using
the schema is as follows. It uses the jsonschema python module:
cat > jschema.py << __EOF__
import json
from jsonschema import validate
from jsonschema.validators import Draft3Validator
with open('schema.txt', 'r') as f:
schema = json.load(f)
Draft3Validator.check_schema(schema)
with open('instance.txt', 'r') as f:
instance = json.load(f)
validate(instance, schema, Draft3Validator)
__EOF__
$ echo "show schema json" | socat /var/run/haproxy.stat stdio > schema.txt
$ echo "show info json" | socat /var/run/haproxy.stat stdio > instance.txt
python ./jschema.py
$ echo "show stats json" | socat /var/run/haproxy.stat stdio > instance.txt
python ./jschema.py
Signed-off-by: Simon Horman <horms@verge.net.au>
Add a json parameter to show (info|stat) which will output information
in JSON format. A follow-up patch will add a JSON schema which describes
the format of the JSON output of these commands.
The JSON output is without any extra whitespace in order to reduce the
volume of output. For human consumption passing the output through a
pretty printer may be helpful.
e.g.:
$ echo "show info json" | socat /var/run/haproxy.stat stdio | \
python -m json.tool
STAT_STARTED has bee added in order to track if show output has begun or
not. This is used in order to allow the JSON output routines to only insert
a "," between elements when needed. I would value any feedback on how this
might be done better.
Signed-off-by: Simon Horman <horms@verge.net.au>
Move the "show info" command to stats.c using the CLI keyword API
to register it on the CLI. The stats_dump_info_to_buffer() function
is now static again. Note, we don't need proto_ssl anymore in cli.c.
proto/dumpstats.h has been split in 4 files:
* proto/cli.h contains protypes for the CLI
* proto/stats.h contains prototypes for the stats
* types/cli.h contains definition for the CLI
* types/stats.h contains definition for the stats
