Troubleshooting and monitoring
This page offers detailed guidance for troubleshooting and monitoring your Zulip installation. If you suspect that you have encountered a bug, or are otherwise unable to resolve an issue with your Zulip installation, best-effort community support is available in the Zulip development community . We provide free, interactive support for the vast majority of questions about running a Zulip server.
To report a problem or ask a question, please start a new topic in the #production help channel in the Zulip development community :
Describe what you are trying to do and any problems you’ve encountered.
Provide the relevant logs, such as the full traceback from the bottom of
/var/log/zulip/errors.log
, or the installation script logs at/var/log/zulip/install.log
. Please post logging output using code blocks, not screenshots.Be sure to include what version of Zulip Server you are running, or between which versions you are upgrading.
Contact sales@zulip.com if you’d like to learn about paid support options, including phone support from Zulip’s core engineering team.
Overview and resources
If you encounter issues while self-hosting Zulip, the first thing to
do is look at Zulip’s logs, which are located in /var/log/zulip/
.
That directory contains one log file for each service, plus
errors.log
(has all errors and the first place you should check),
server.log
(has logs from the Django and Tornado servers), and
workers.log
(has combined logs from the queue workers). Zulip also
provides a tool to search through server.log
.
Zulip uses Supervisor to monitor and control its many Python services. Read the next section, Using supervisorctl, to learn how to use the Supervisor client to monitor and manage services.
If you haven’t already, now might be a good time to read Zulip’s architectural overview, particularly the Components section. This will help you understand the many services Zulip uses.
The section troubleshooting services on this page includes details about how to fix common issues with Zulip services.
Using supervisorctl
To see what Zulip-related services are configured to
use Supervisor, look at /etc/supervisor/conf.d/zulip.conf
and
/etc/supervisor/conf.d/zulip-db.conf
.
Use the supervisor client supervisorctl
to list the status of, stop, start,
and restart various services.
Checking status with supervisorctl status
You can check if the Zulip application is running using:
supervisorctl status
When everything is running as expected, you will see something like this:
process-fts-updates RUNNING pid 11392, uptime 19:40:06
smokescreen RUNNING pid 3113, uptime 29 days, 21:58:32
zulip-django RUNNING pid 11441, uptime 19:39:57
zulip-tornado RUNNING pid 11397, uptime 19:40:03
zulip_deliver_scheduled_emails RUNNING pid 10289, uptime 19:41:04
zulip_deliver_scheduled_messages RUNNING pid 10294, uptime 19:41:02
zulip-workers:zulip_events_deferred_work RUNNING pid 10314, uptime 19:41:00
zulip-workers:zulip_events_digest_emails RUNNING pid 10339, uptime 19:40:57
zulip-workers:zulip_events_email_mirror RUNNING pid 10751, uptime 19:40:52
zulip-workers:zulip_events_email_senders RUNNING pid 10769, uptime 19:40:49
zulip-workers:zulip_events_embed_links RUNNING pid 11035, uptime 19:40:46
zulip-workers:zulip_events_embedded_bots RUNNING pid 11139, uptime 19:40:43
zulip-workers:zulip_events_invites RUNNING pid 11261, uptime 19:40:36
zulip-workers:zulip_events_missedmessage_emails RUNNING pid 11346, uptime 19:40:21
zulip-workers:zulip_events_missedmessage_mobile_notifications RUNNING pid 11351, uptime 19:40:19
zulip-workers:zulip_events_outgoing_webhooks RUNNING pid 11358, uptime 19:40:17
zulip-workers:zulip_events_user_activity RUNNING pid 11365, uptime 19:40:14
zulip-workers:zulip_events_user_activity_interval RUNNING pid 11376, uptime 19:40:11
zulip-workers:zulip_events_user_presence RUNNING pid 11384, uptime 19:40:08
If you see any services showing a status other than RUNNING
, or you
see an uptime under 5 seconds (which indicates it’s crashing
immediately after startup and repeatedly restarting), that service
isn’t running. If you don’t see relevant logs in
/var/log/zulip/errors.log
, check the log file declared via
stdout_logfile
for that service’s entry in
/etc/supervisor/conf.d/zulip.conf
for details. Logs only make it to
/var/log/zulip/errors.log
once a service has started fully.
Restarting services with supervisorctl restart
After you change configuration in /etc/zulip/settings.py
or fix a
misconfiguration, you will often want to restart the Zulip
application. In order to restart all of Zulip’s services, you can use:
/home/zulip/deployments/current/scripts/restart-server
If you want to restart just one of them, you can use
supervisorctl
:
# You can use this for any service found in `supervisorctl list`
supervisorctl restart zulip-django
Warning
A configuration file might be used by multiple services, so generally
scripts/restart-server
is the correct tool to use for reloading
purposes. Only use supervisorctl restart
for an individual service
if you’re confident that this specific service requires restarting.
In particular, it is not the right tool for applying settings changes
in /etc/zulip/settings.py
and may cause inconsistent behavior.
Stopping services with supervisorctl stop
Similarly, while stopping all of Zulip is best done by running
scripts/stop-server
, you can stop individual Zulip services using:
# You can use this for any service found in `supervisorctl list`
supervisorctl stop zulip-django
Troubleshooting services
The Zulip application uses several major open source services to store and cache data, queue messages, and otherwise support the Zulip application:
PostgreSQL
RabbitMQ
nginx
Redis
memcached
If one of these services is not installed or functioning correctly, Zulip will not work. Below we detail some common configuration problems and how to resolve them:
If your browser reports no webserver is running, that is likely because nginx is not configured properly and thus failed to start. nginx will fail to start if you configured SSL incorrectly or did not provide SSL certificates. To fix this, configure them properly and then run:
service nginx restart
If your host is being port scanned by unauthorized users, you may see messages in
/var/log/zulip/server.log
like2017-02-22 14:11:33,537 ERROR Invalid HTTP_HOST header: '10.2.3.4'. You may need to add u'10.2.3.4' to ALLOWED_HOSTS.
Django uses the hostnames configured in
ALLOWED_HOSTS
to identify legitimate requests and block others. When an incoming request does not have the correct HTTP Host header, Django rejects it and logs the attempt. For more on this issue, see the Django release notes on Host header poisoningAn AMQPConnectionError traceback or error running rabbitmqctl usually means that RabbitMQ is not running; to fix this, try:
service rabbitmq-server restart
If RabbitMQ fails to start, the problem is often that you are using a virtual machine with broken DNS configuration; you can often correct this by configuring
/etc/hosts
properly.
Restrict unattended upgrades
Important
We recommend that you disable or limit Ubuntu’s unattended-upgrades to skip some server packages. With unattended upgrades enabled but not limited, the moment a new PostgreSQL release is published, your Zulip server will have its PostgreSQL server upgraded (and thus restarted). If you do disable unattended-upgrades, do not forget to regularly install apt upgrades manually!
Restarting one of the system services that Zulip uses (PostgreSQL, memcached, Redis, or RabbitMQ) will drop the connections that Zulip processes have to the service, resulting in future operations on those connections throwing errors.
Zulip is designed to recover from system service downtime by creating new connections once the system service is back up, so the Zulip outage will end once the system service finishes restarting. But you’ll get a bunch of error emails during the system service outage whenever one of the Zulip server’s ~20 workers attempts to access the system service.
An unplanned outage will also result in an annoying (and potentially confusing) trickle of error emails over the following hours or days. These emails happen because a worker only learns its connection was dropped when it next tries to access the connection (at which point it’ll send an error email and make a new connection), and several workers are commonly idle for periods of hours or days at a time.
You can prevent this trickle when doing a planned upgrade by
restarting the Zulip server with
/home/zulip/deployments/current/scripts/restart-server
after
installing system package updates to PostgreSQL, memcached,
RabbitMQ, or Redis.
You can ensure that the unattended-upgrades
package never upgrades
PostgreSQL, memcached, Redis, or RabbitMQ, by configuring in
/etc/apt/apt.conf.d/50unattended-upgrades
:
// Python regular expressions, matching packages to exclude from upgrading
Unattended-Upgrade::Package-Blacklist {
"libc\d+";
"memcached$";
"nginx-full$";
"postgresql-\d+$";
"rabbitmq-server$";
"redis-server$";
"supervisor$";
};
Monitoring
Chat is mission-critical to many organizations. This section contains advice on monitoring your Zulip server to minimize downtime.
First, we should highlight that Zulip sends Django error emails to
ZULIP_ADMINISTRATOR
for any backend exceptions. A properly
functioning Zulip server shouldn’t send any such emails, so it’s worth
reporting/investigating any that you do see.
Beyond that, the most important monitoring for a Zulip server is standard stuff:
Basic host health monitoring for issues running out of disk space, especially for the database and where uploads are stored.
Service uptime and standard monitoring for the services Zulip depends on. Most monitoring software has standard plugins for nginx, PostgreSQL, Redis, RabbitMQ, and memcached, and those will work well with Zulip.
supervisorctl status
showing all servicesRUNNING
.Checking for processes being OOM killed.
Beyond that, Zulip ships a few application-specific end-to-end health
checks. The Nagios plugins check_send_receive_time
,
check_rabbitmq_queues
, and check_rabbitmq_consumers
are generally
sufficient to point to the cause of any Zulip production issue. See
the next section for details.
Nagios configuration
The complete Nagios configuration (sans secret keys) used to
monitor zulip.com is available under puppet/kandra
in the
Zulip Git repository (those files are not installed in the release
tarballs).
The Nagios plugins used by that configuration are installed
automatically by the Zulip installation process in subdirectories
under /usr/lib/nagios/plugins/
. The following is a summary of the
useful Nagios plugins included with Zulip and what they check:
Application server and queue worker monitoring:
check_send_receive_time
: Sends a test message through the system between two bot users to check that end-to-end message sending works. An effective end-to-end check for Zulip’s Django and Tornado systems being healthy.check_rabbitmq_consumers
andcheck_rabbitmq_queues
: Effective checks for Zulip’s RabbitMQ-based queuing systems being healthy.check_worker_memory
: Monitors for memory leaks in queue workers.
Database monitoring:
check_fts_update_log
: Checks whether full-text search updates are being processed properly or getting backlogged.check_postgres
: General checks for database health.check_postgresql_replication_lag
: Checks whether PostgreSQL streaming replication is up to date.
Standard server monitoring:
check_debian_packages
: Checks whether the system is behind onapt upgrade
.
If you’re using these plugins, bug reports and pull requests to make it easier to monitor Zulip and maintain it in production are encouraged!
Memory leak mitigation
As a measure to mitigate the potential impact of any future memory
leak bugs in one of the Zulip daemons, Zulip service automatically
restarts itself every Sunday early morning. See
/etc/cron.d/restart-zulip
for the precise configuration.
Troubleshooting the Zulip installer
Important
The Zulip installer is designed to be idempotent: if the script fails, once you’ve corrected the cause of the failure, you can just rerun the script.
The install script automatically logs a transcript to
/var/log/zulip/install.log
. In case of failure, you might find the
log handy for resolving the issue. Please include a copy of this log
file in any bug reports.
If you get an error after scripts/setup/install
completes, check the bottom of
/var/log/zulip/errors.log
for a traceback, and consult the rest of this
page for advice on how to debug or get help.
The zulip
user’s password.
By default, the zulip
user doesn’t
have a password, and is intended to be accessed by su zulip
from the
root
user (or via SSH keys or a password, if you want to set those
up, but that’s up to you as the system administrator). Most people
who are prompted for a password when running su zulip
turn out to
already have switched to the zulip
user earlier in their session,
and can just skip that step.