Secure, maintain, and upgrade¶
This page covers topics that will help you maintain a healthy, up-to-date, and secure Zulip installation, including:
You may also want to read this related content:
We recommend reading this entire section before doing your first upgrade.
To upgrade to a new version of the zulip server, download the appropriate release tarball from https://www.zulip.org/dist/releases/.
Next, run as root:
The upgrade process will shut down the Zulip service and then run
apt-get upgrade, a
puppet apply, any database migrations, and then bring the Zulip service back
up. Upgrading will result in some brief downtime for the service, which should be
under 30 seconds unless there is an expensive transition involved. Unless you
have tested the upgrade in advance, we recommend doing upgrades at off hours.
(Note that there are separate instructions for upgrading Zulip if you’re using Docker.)
Upgrading the distro¶
Note that upgrading an existing Zulip production server from Ubuntu 14.04 Trusty to Ubuntu 16.04 Xenial (or 16.04 Xenial to 18.04 Bionic) will require significant manual intervention on your part to migrate the data in the database from Postgres 9.3 to Postgres 9.5. Contributions on testing and documenting this process are welcome!
Preserving local changes to configuration files¶
Warning: If you have modified configuration files installed by
Zulip (e.g. the nginx configuration), the Zulip upgrade process will
overwrite your configuration when it does the
You can test whether this will happen assuming no upstream changes to
the configuration using
scripts/zulip-puppet-apply (without the
-f option), which will do a test puppet run and output and changes
it would make. Using this list, you can save a copy of any files
that you’ve modified, do the upgrade, and then restore your
If you need to do this, please report the issue so that we can make the Zulip puppet configuration flexible enough to handle your setup.
Troubleshooting with the upgrade log¶
The Zulip upgrade script automatically logs output to
/var/log/zulip/upgrade.log. Please use those logs to include output
that shows all errors in any bug reports.
After the upgrade, we recommend checking
to confirm that your users are not experiencing errors after the
Rolling back to a prior version¶
The Zulip upgrade process works by creating a new deployment under
/home/zulip/deployments/ containing a complete copy of the Zulip server code,
and then moving the symlinks at
as part of the upgrade process.
This means that if the new version isn’t working,
you can quickly downgrade to the old version by running
/home/zulip/deployments/last/scripts/restart-server, or to an
earlier previous version by running
restart-server script stops any running Zulip server, and starts
the version corresponding to the
restart-server path you call.
If required, you can update your settings by editing
and then run
restart the server.
Applying system updates¶
The Zulip upgrade script will automatically run
apt-get update and
apt-get upgrade, to make sure you have any new versions of
dependencies (this will also update system packages). We assume that
you will install security updates from
apt regularly, according to
your usual security practices for a production server.
If you’d like to minimize downtime when installing a Zulip server
upgrade, you may want to do an
apt-get upgrade (and then restart the
server and check everything is working) before running the Zulip
apt package to be careful about: upgrading
while the server is running may result in an outage (basically,
postgresql might stop accepting new queries but refuse to shut down
while waiting for connections from the Zulip server to shut down).
While this only happens sometimes, it can be hard to fix for someone
who isn’t comfortable managing a
postgresql database . You can
avoid that possibility with the following procedure (run as root):
apt-get update supervisorctl stop all apt-get upgrade -y supervisorctl start all
 If this happens to you, just stop the Zulip server, restart postgres, and then start the Zulip server again, and you’ll be back in business.
Disabling unattended upgrades¶
Important: We recommend that you disable Ubuntu’s unattended-upgrades, and instead install apt upgrades manually. With unattended upgrades enabled, the moment a new Postgres release is published, your Zulip server will have its postgres server upgraded (and thus restarted).
When one of the services Zulip depends on (postgres, memcached, redis, rabbitmq) is restarted, that services will disconnect everything using them (like the Zulip server), and every operation that Zulip does which uses that service will throw an exception (and send you an error report email). These apparently “random errors” can be confusing and might cause you to worry incorrectly about the stability of the Zulip software, which in fact the problem is that Ubuntu automatically upgraded and then restarted key Zulip dependencies.
Instead, we recommend installing updates for these services manually,
and then restarting the Zulip server with
API and your Zulip URL¶
To use the Zulip API with your Zulip server, you will need to use the
API endpoint of e.g.
https://zulip.example.com/api. Our Python
API example scripts support this via the
--site=https://zulip.example.com argument. The API bindings
support it via putting
site=https://zulip.example.com in your
Every Zulip integration supports this sort of argument (or e.g. a
ZULIP_SITE variable in a zuliprc file or the environment), but this
is not yet documented for some of the integrations (the included
integration documentation on
/integrations will properly document
how to do this for most integrations). We welcome pull requests for
integrations that don’t discuss this!
Similarly, you will need to instruct your users to specify the URL for your Zulip server when using the Zulip desktop and mobile apps.
Memory leak mitigation¶
As a measure to mitigate the impact of potential memory leaks in one
of the Zulip daemons, the service automatically restarts itself
every Sunday early morning. See
/etc/cron.d/restart-zulip for the
Upgrading from a git repository¶
Zulip supports upgrading a production installation to any commit in Git, which is great for running pre-release versions or maintaining a small fork. If you’re using Zulip 1.7 or newer, you can just run the command:
# Upgrade to a tagged release /home/zulip/deployments/current/scripts/upgrade-zulip-from-git 1.8.1 # Upgrade to a branch or other Git ref /home/zulip/deployments/current/scripts/upgrade-zulip-from-git master
and Zulip will automatically fetch the relevant Git commit and upgrade to the that version of Zulip.
By default, this uses the main upstream Zulip server repository
(example below), but you can configure any other Git repository by
adding a section like this to
[deployment] git_repo_url = https://github.com/zulip/zulip.git
Upgrading using Git from Zulip 1.6 and older¶
If you’re are upgrading from a Git repository, and you currently have
Zulip 1.6 or older installed, you will need to install the
dependencies for building Zulip’s static assets. To do this, add
zulip::static_asset_compiler to your
puppet_classes entry, like this:
puppet_classes = zulip::voyager, zulip::static_asset_compiler
scripts/zulip-puppet-apply. After approving the changes,
you’ll be able to use
After you’ve upgraded to Zulip 1.7 or above, you can safely remove
puppet_classes; in Zulip 1.7 and
above, it is a dependency of
zulip::voyager and thus these
dependencies are installed by default.
There are several pieces of data that you might want to back up:
- The postgres database. That you can back up like any postgres
database; we have some example tooling for doing that incrementally
into S3 using wal-e in
puppet/zulip_ops/manifests/postgres_common.pp(that’s what we use for zulip.com’s database backups). Note that this module isn’t part of the Zulip server releases since it’s part of the zulip.com configuration (see https://github.com/zulip/zulip/issues/293 for a ticket about fixing this to make life easier for running backups).
- Any user-uploaded files. If you’re using S3 as storage for file
uploads, this is backed up in S3, but if you have instead set
LOCAL_UPLOADS_DIR, any files uploaded by users (including avatars) will be stored in that directory and you’ll want to back it up.
- Your Zulip configuration including secrets from
/etc/zulip/. E.g. if you lose the value of
secret_key, all users will need to login again when you setup a replacement server since you won’t be able to verify their cookies; if you lose
avatar_salt, any user-uploaded avatars will need to be re-uploaded (since avatar filenames are computed using a hash of
avatar_saltand user’s email), etc.
- The logs under
/var/log/zulipcan be handy to have backed up, but they do get large on a busy server, and it’s definitely lower-priority.
If you are interested in backups because you are moving from one Zulip server to another server and can’t transfer a full postgres dump (which is definitely the simplest approach), our draft conversion and export design document may help. The tool is well designed, and was tested carefully with dozens of realms in mid-2016; but it’s not integrated into Zulip’s regular testing process, and thus it is worth asking on the Zulip developers mailing list whether it needs any minor updates to do things like export newly added tables.
Restore from backups¶
To restore from backups, the process is basically the reverse of the above:
- Install new server as normal by downloading a Zulip release tarball
and then using
scripts/setup/install, you don’t need to run the
initialize-databasesecond stage which puts default data into the database.
- Unpack to
zulip-secrets.conffiles from your backups.
- Restore your database from the backup using
wal-e; if you ran
initialize-databaseanyway above, you’ll want to first
scripts/setup/postgres-init-dbto drop the initial database first.
- Reconfigure rabbitmq to use the password from
secrets.confby running, as root,
- If you’re using local file uploads, restore those files to the path
settings.LOCAL_UPLOADS_DIRand (if appropriate) any logs.
- Start the server using
This restoration process can also be used to migrate a Zulip installation from one server to another.
We recommend running a disaster recovery after you setup backups to
confirm that your backups are working; you may also want to monitor
that they are up to date using the Nagios plugin at:
Contributions to more fully automate this process or make this section of the guide much more explicit and detailed are very welcome!
Postgres streaming replication¶
Zulip has database configuration for using Postgres streaming replication; you can see the configuration in these files:
Contribution of a step-by-step guide for setting this up (and moving
this configuration to be available in the main
would be very welcome!
The complete Nagios configuration (sans secret keys) used to
monitor zulip.com is available under
puppet/zulip_ops in the
Zulip Git repository (those files are not installed in the release
The Nagios plugins used by that configuration are installed
automatically by the Zulip installation process in subdirectories
/usr/lib/nagios/plugins/. The following is a summary of the
various 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)
check_rabbitmq_queues(checks for rabbitmq being down or the queue workers being behind)
check_queue_worker_errors(checks for errors reported by the queue workers)
check_worker_memory(monitors for memory leaks in queue workers)
check_email_deliverer_process(monitors for whether outgoing emails are being sent)
check_postgres_replication_lag(checks streaming replication is up to date).
check_postgres(checks the health of the postgres database)
check_postgres_backup(checks backups are up to date; see above)
check_fts_update_log(monitors for whether full-text search updates are being processed)
Standard server monitoring:
check_website_response.sh(standard HTTP check)
check_debian_packages(checks apt repository is up to date)
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!
This section attempts to address the considerations involved with running Zulip with larger teams (especially >1000 users).
- For an organization with 100+ users, it’s important to have more than 4GB of RAM on the system. Zulip will install on a system with 2GB of RAM, but with less than 3.5GB of RAM, it will run its queue processors multithreaded to conserve memory; this creates a significant performance bottleneck.
- chat.zulip.org, with thousands of user accounts and thousands of messages sent every week, has 8GB of RAM, 4 cores, and 80GB of disk. The CPUs are essentially always idle, but the 8GB of RAM is important.
- We recommend using a remote postgres database for isolation, though it is not required. In the following, we discuss a relatively simple configuration with two types of servers: application servers (running Django, Tornado, RabbitMQ, Redis, Memcached, etc.) and database servers.
- You can scale to a pretty large installation (O(~1000) concurrently
active users using it to chat all day) with just a single reasonably
large application server (e.g. AWS c3.2xlarge with 8 cores and 16GB
of RAM) sitting mostly idle (<10% CPU used and only 4GB of the 16GB
RAM actively in use). You can probably get away with half that
(e.g. c3.xlarge), but ~8GB of RAM is highly recommended at scale.
Beyond a 1000 active users, you will eventually want to increase the
memory cap in
memcached.conffrom the default 512MB to avoid high rates of memcached misses.
- For the database server, we highly recommend SSD disks, and RAM is
the primary resource limitation. We have not aggressively tested
for the minimum resources required, but 8 cores with 30GB of RAM
(e.g. AWS’s m3.2xlarge) should suffice; you may be able to get away
with less especially on the CPU side. The database load per user is
pretty optimized as long as
memcachedis working correctly. This has not been tested, but from extrapolating the load profile, it should be possible to scale a Zulip installation to 10,000s of active users using a single large database server without doing anything complicated like sharding the database.
- For reasonably high availability, it’s easy to run a hot spare application server and a hot spare database (using Postgres streaming replication; see the section on configuring this). Be sure to check out the section on backups if you’re hoping to run a spare application server; in particular you probably want to use the S3 backend for storing user-uploaded files and avatars and will want to make sure secrets are available on the hot spare.
- Zulip does not support dividing traffic for a given Zulip realm between multiple application servers. There are two issues: you need to share the memcached/Redis/RabbitMQ instance (these should can be moved to a network service shared by multiple servers with a bit of configuration) and the Tornado event system for pushing to browsers currently has no mechanism for multiple frontend servers (or event processes) talking to each other. One can probably get a factor of 10 in a single server’s scalability by supporting multiple tornado processes on a single server, which is also likely the first part of any project to support exchanging events amongst multiple servers.
Questions, concerns, and bug reports about this area of Zulip are very welcome! This is an area we are hoping to improve.
Zulip has a large library of Django management
To use them, you will want to be logged in as the
zulip user and for
the purposes of this documentation, we assume the current working
Below, we show several useful examples, but there are more than 100 in total. We recommend skimming the usage docs (or if there are none, the code) of a management command before using it, since they are generally less polished and more designed for expert use than the rest of the Zulip system.
You can get an iPython shell with full access to code within the Zulip
manage.py shell, e.g., you can do the following to
change an email address:
$ /home/zulip/deployments/current/manage.py shell In : user_profile = get_user_profile_by_email("email@example.com") In : do_change_user_email(user_profile, "firstname.lastname@example.org")
This will start a postgres shell connected to the Zulip database.
Grant administrator access¶
You can make any user a realm administrator on the command line with
knight management command:
./manage.py knight email@example.com -f
Creating API super users with manage.py¶
If you need to manage the IRC, Jabber, or Zephyr mirrors, you will
need to create API super users. To do this, use
--permission=api_super_user argument. See the respective
integration scripts for these mirrors (under
zulip/integrations/ in the Zulip Python API
repo) for further detail on these.
Exporting users and realms with manage.py export¶
If you need to do an export of a single user or of an entire realm, we
have tools in
management/ that essentially export Zulip data to the
export_single_user.py exports the message history and realm-public
metadata for a single Zulip user (including that user’s received
messages as well as their sent messages).
A good overview of the process for exporting a single realm when moving a realm to a new server (without moving a full database dump) is in management/export.py. We recommend you read the comment there for words of wisdom on speed, what is and is not exported, what will break upon a move to a new server, and suggested procedure.
Other useful manage.py commands¶
There are a large number of useful management commands under
zerver/management/commands/; you can also see them listed using
./manage.py with no arguments.