The previous model for these Nagios checks was kinda crazy -- every
minute, we'd run a full `rabbitmctl list_consumers` for each of the
dozen+ consumers that we have, and then do the exact same parsing
logic for each to determine whether the target queue has a running
consumer to write out a state file.
Because `rabbitmctl list_consumers` takes a small amount of resources,
on systems where CPU is very limited (e.g. t2 style AWS instances),
this minor CPU wastage could be problematic.
Now we just do that `rabbitmqctl list_consumers` once per minute, and
output all the state files from a single command.
Further TODO items on this front include removing the hardcoded list
of queues.
Because rabbitmq doesn't support changing the nodename of a running
rabbitmq node, Zulip installations suffered a plague of issues where
e.g. a Zulip server would reboot, the hostname would change, and
suddenly the local rabbitmq instance being used by Zulip would stop
working.
We address this problem by using, by default, a fixed rabbitmq
nodename, but providing server administrators the option to set the
rabbitmq nodename used by Zulip however they choose.
To upgrade an existing server to use this new configuration, one will
need to add something like the following to /etc/zulip/zulip.conf:
[rabbitmq]
nodename = zulip@localhost
However, I don't believe we have the puppet code in place to make this
work correctly at initial installation without rabbitmq-server being
already installed (but off), as we can easily setup in Travis CI but I
haven't been willing to do for the installer. So for now, this just
fixes our Travis CI problems.
Fixes: #1579.
Previously, we used a fixed memcached memory allocation of 512MB,
regardless of the size of the server. While that is a good allocation
for a server with 4GB of RAM, for servers with less, we should
decrease the allocation, and for a large server with much more RAM, we
should increase it. We still support the user overriding the
configuration setting, but this produces more sensible defaults.
Zulip had only patches the redis configuration in one small way, which
resulted in unnecessary portability issues for using Redis on
different versions of Linux. We replace this with just a adding an
include mechanism to the redis config.
While we're at it, we configure this to take advantage of the
new REDIS_PASSWORD secret to automatically configure redis passwords.
* Fixes passing a string argument rather than an actual Python
argument.
* Switches to hardcoding the database to connect to rather than the
user, so this check can be run as an arbitrary user.
All other zulip management command names have underscores, so
rename email-mirror to email_mirror.
This will also make it possible to import this module, which will
help in writing tests for it.
Tim Abbott
Tim Abbott
Eklavya Sharma