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Backups, export and import

Zulip has high quality export and import tools that can be used to move data from one Zulip server to another, do backups, compliance work, or migrate from your own servers to the hosted Zulip Cloud service (or back):

  • The Backup tool is designed for exact restoration of a Zulip server's state, for disaster recovery, testing with production data, or hardware migration. This tool has a few limitations:

    • Backups must be restored on a server running the same Zulip version (most precisely, one where manage.py showmigrations has the same output).
    • Backups must be restored on a server running the same postgres version.
    • Backups aren't useful for migrating organizations between self-hosting and Zulip Cloud (which may require renumbering all the users/messages/etc.).

    We highly recommend this tool in situations where it is applicable, because it is highly optimized and highly stable, since the hard work is done by the built-in backup feature of postgres. We also document backup details for users managing backups manually.

  • The logical Data export tool is designed for migrating data between Zulip Cloud and other Zulip servers, as well as various auditing purposes. The logical export tool produces a .tar.gz archive with most of the Zulip database data encoded in JSON files–a format shared by our data import tools for third-party services like Slack.

    Like the backup tool, logical data exports must be imported on a Zulip server running the same version. However, logical data exports can be imported on Zulip servers running a different postgres version or hosting a different set of Zulip organizations. We recommend this tool in cases where the backup tool isn't applicable, including situations where an easily machine-parsable export format is desired.

  • Zulip also has an HTML archive tool, which is primarily intended for public archives, but can also be useful to inexpensively preserve public stream conversations when decommissioning a Zulip organization.

  • It's possible to setup postgres streaming replication and the S3 file upload backend as part of a high evailability environment.

Backups

The Zulip server has a built-in backup tool:

# As the zulip user
/home/zulip/deployments/current/manage.py backup
# Or as root
su zulip -c '/home/zulip/deployments/current/manage.py backup'

The backup tool provides the following options:

  • --output=/tmp/backup.tar.gz: Filename to write the backup tarball to (default: write to a file in /tmp). On success, the console output will show the path to the output tarball.
  • --skip-db: Skip backup of the database. Useful if you're using a remote postgres host with its own backup system and just need to backup non-database state.
  • --skip-uploads: If LOCAL_UPLOADS_DIR is set, user-uploaded files in that directory will be ignored.

This will generate a .tar.gz archive containing all the data stored on your Zulip server that would be needed to restore your Zulip server's state on another machine perfectly.

Restoring backups

First, install a new Zulip server through Step 3 with the same version of both the base OS and Zulip from your previous installation. Then, run as root:

/home/zulip/deployments/current/scripts/setup/restore-backup /path/to/backup

When that finishes, your Zulip server should be fully operational again.

Changing the hostname

It's common, when testing backup restoration, to restore backups with a different user-facing hostname than the original server to avoid disrupting service (e.g. zuliptest.example.com rather than zulip.example.com).

If you do so, just like any other time you change the hostname, you'll need to update EXTERNAL_HOST and then restart the Zulip server (after backup restoration completes).

Until you do, your Zulip server will think its user-facing hostname is still zulip.example.com and will return HTTP 400 BAD REQUEST errors when trying to access it via zuliptest.example.com.

Inspecting a backup tarball

If you're not sure what versions were in use when a given backup was created, you can get that information via the files in the backup tarball: postgres-version, os-version, and zulip-version. The following command may be useful for viewing these files without extracting the entire archive.

tar -Oaxf /path/to/archive/zulip-backup-rest.tar.gz zulip-backup/zulip-version

What is included

Backups contain everything you need to fully restore your Zulip server, including the database, settings, secrets from /etc/zulip, and user-uploaded files stored on the Zulip server.

The following data is not included in these backup archives, and you may want to backup separately:

  • The server access/error logs from /var/log/zulip. The Zulip server only appends to logs, and they can be very large compared to the rest of the data for a Zulip server.

  • Files uploaded with the Zulip S3 file upload backend. We don't include these for two reasons. First, the uploaded file data in S3 can easily be many times larger than the rest of the backup, and downloading it all to a server doing a backup could easily exceed its disk capacity. Additionally, S3 is a reliable persistent storage system with its own high-quality tools for doing backups.

  • SSL certificates. These are not included because they are particularly security-sensitive and are either trivially replaced (if generated via Certbot) or provided by the system administrator.

For completeness, Zulip's backups do not include certain highly transient state that Zulip doesn't store in a database. For example, typing status data, API rate-limiting counters, and RabbitMQ queues that are essentially always empty in a healthy server (like outgoing emails to send). You can check whether these queues are empty using rabbitmqctl list_queues.

Backup details

This section is primarily for users managing backups themselves (E.g. if they're using a remote postgres database with an existing backup strategy), and also serves as documentation for what is included in the backups generated by Zulip's standard tools. The data includes:

  • The postgres database. You can back it up like any postgres database. We have some example tooling for doing that incrementally into S3 using wal-g in puppet/zulip/manifests/postgres_backups.pp. In short, this requires:

    • Zulip 1.4 or newer release.
    • An Amazon S3 bucket for storing the backups.
    • /etc/zulip/zulip-secrets.conf on the postgres server like this: 
      [secrets]
s3_backups_key = # aws public key
s3_backups_secret_key =  # aws secret key
s3_backups_bucket = # name of S3 backup
    • A cron job to run /usr/local/bin/pg_backup_and_purge.py. There's puppet config for this in puppet/zulip/manifests/postgres_backups.pp.
    • Verification that backups are running via /usr/lib/nagios/plugins/zulip_postgres_backups/check_postgres_backup.

  • 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_salt and user's email), etc.

Restore from manual backups

To restore from a manual backup, 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-database second stage which puts default data into the database.

  • Unpack to /etc/zulip the settings.py and zulip-secrets.conf files from your backups.

  • If you ran initialize-database anyway above, you'll want to run scripts/setup/postgres-init-db to drop the initial database first.

  • Restore your database from the backup.

  • Reconfigure rabbitmq to use the password from secrets.conf by running, as root, scripts/setup/configure-rabbitmq.

  • If you're using local file uploads, restore those files to the path specified by settings.LOCAL_UPLOADS_DIR and (if appropriate) any logs.

  • Start the server using scripts/restart-server.

This restoration process can also be used to migrate a Zulip installation from one server to another.

We recommend running a disaster recovery after setting up your 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: puppet/zulip/files/nagios_plugins/zulip_postgres_backups/check_postgres_backup.

Postgres streaming replication

Zulip has database configuration for using Postgres streaming replication. You can see the configuration in these files:

  • puppet/zulip_ops/manifests/postgres_appdb.pp
  • puppet/zulip_ops/files/postgresql/*

We use this configuration for Zulip Cloud, and it works well in production, but it's not fully generic. Contributions to make it a supported and documented option for other installations are appreciated.

Data export

Zulip's powerful data export tool is designed to handle migration of a Zulip organization between different hardware platforms; as a result, these exports contain all non-transient data for a Zulip organization, with the exception of passwords and API keys.

We recommend using the backup tool if your primary goal is backups.

Preventing changes during the export

For best results, you'll want to shut down access to the organization before exporting; so that nobody can send new messages (etc.) while you're exporting data. There are two ways to do this:

  1. supervisorctl stop all, which stops the whole server. This is preferred if you're not hosting multiple organizations, because it has no side effects other than disabling the Zulip server for the duration.
  2. manage.py deactivate_realm -r 'target_org', which deactivates the target organization, logging out all active login sessions and preventing all accounts from logging in or accessing the API. This is preferred for environments like Zulip Cloud where you might want to export a single organization without disrupting any other users, and the intent is to move hosting of the organization (and forcing users to re-login would be required as part of the hosting migration anyway).

We include both options in the instructions below, commented out so that neither runs (using the # at the start of the lines). If you'd like to use one of these options, remove the # at the start of the lines for the appropriate option.

Export your Zulip data

Log in to a shell on your Zulip server as the zulip user. Run the following commands:

cd /home/zulip/deployments/current
# supervisorctl stop all # Stops the Zulip server
# ./manage.py deactivate_realm -r ''  # Deactivates the organization
./manage.py export -r ''  # Exports the data

(The -r option lets you specify the organization to export; '' is the default organization hosted at the Zulip server's root domain.)

This will generate a tarred archive with a name like /tmp/zulip-export-zcmpxfm6.tar.gz. The archive contains several JSON files (containing the Zulip organization's data) as well as an archive of all the organization's uploaded files.

Import into a new Zulip server

  1. Install a new Zulip server, skipping Step 3 (you'll create your Zulip organization via the data import tool instead).

    • Ensure that the Zulip server you're importing into is running the same version of Zulip as the server you're exporting from.

    • For exports from Zulip Cloud (zulip.com), you need to upgrade to master, since we run run master on Zulip Cloud:

      /home/zulip/deployments/current/scripts/upgrade-zulip-from-git master

      It is not sufficient to be on the latest stable release, as zulip.com runs pre-release versions of Zulip that are often several months of development ahead of the latest release.

    • Note that if your server has limited free RAM, you'll want to shut down the Zulip server with supervisorctl stop all while you run the import, since our minimal system requirements do not budget extra RAM for running the data import tool.

  2. If your new Zulip server is meant to fully replace a previous Zulip server, you may want to copy some settings from /etc/zulip to your new server to reuse the server-level configuration and secret keys from your old server. There are a few important details to understand about doing so:

    • Copying /etc/zulip/settings.py and /etc/zulip/zulip.conf is safe and recommended. Care is required when copying secrets from /etc/zulip/zulip-secrets.conf (details below).
    • If you copy zulip_org_id and zulip_org_key (the credentials for the mobile push notifications service), you should be very careful to make sure the no users had their IDs renumbered during the import process (this can be checked using manage.py shell with some care). The push notifications service has a mapping of which user_id values are associated with which devices for a given Zulip server (represented by the zulip_org_id registration). This means that if any user_id values were renumbered during the import and you don't register a new zulip_org_id, push notifications meant for the user who now has ID 15 may be sent to devices registered by the user who had user ID 15 before the data export (yikes!). The solution is simply to not copy these settings and re-register your server for mobile push notifications if any users had their IDs renumbered during the logical export/import process.
    • If you copy the rabbitmq_password secret from zulip-secrets.conf, you'll need to run scripts/setup/configure-rabbitmq to update your local RabbitMQ installation to use the password in your Zulip secrets file.
    • You will likely want to copy camo_key (required to avoid breaking certain links) and any settings you added related to authentication and email delivery so that those work on your new server.
    • Copying avatar_salt is not recommended, due to similar issues to the mobile push notifications service. Zulip will automatically rewrite avatars at URLs appropriate for the new user IDs, and using the same avatar salt (and same server URL) post import could result in issues with browsers caching the avatar image improperly for users whose ID was renumbered.

  3. Log in to a shell on your Zulip server as the zulip user. Run the following commands, replacing the filename with the path to your data export tarball:

cd ~
tar -xf /path/to/export/file/zulip-export-zcmpxfm6.tar.gz
cd /home/zulip/deployments/current
./manage.py import '' ~/zulip-export-zcmpxfm6
# supervisorctl start all # Starts the Zulip server
# ./manage.py reactivate_realm -r ''  # Reactivates the organization

This could take several minutes to run depending on how much data you're importing.

Import options

The commands above create an imported organization on the root domain (EXTERNAL_HOST) of the Zulip installation. You can also import into a custom subdomain, e.g. if you already have an existing organization on the root domain. Replace the last two lines above with the following, after replacing <subdomain> with the desired subdomain.

./manage.py import <subdomain> ~/zulip-export-zcmpxfm6
./manage.py reactivate_realm -r <subdomain>  # Reactivates the organization

Logging in

Once the import completes, all your users will have accounts in your new Zulip organization, but those accounts won't have passwords yet (since for security reasons, passwords are not exported). Your users will need to either authenticate using something like Google auth or start by resetting their passwords.

You can use the ./manage.py send_password_reset_email command to send password reset emails to your users. We recommend starting with sending one to yourself for testing:

./manage.py send_password_reset_email -u username@example.com

and then once you're ready, you can email them to everyone using e.g.

./manage.py send_password_reset_email -r '' --all-users

(replace '' with your subdomain if you're using one).

Deleting and re-importing

If you did a test import of a Zulip organization, you may want to delete the test import data from your Zulip server before doing a final import. You can permanently delete all data from a Zulip organization using the following procedure:

realm = Realm.objects.get(string_id="")
realm.delete()

The output contains details on the objects deleted from the database.

Now, exit the management shell and run this to clear Zulip's cache:

/home/zulip/deployments/current/scripts/setup/flush-memcached

Assuming you're using the local file uploads backend, you can additionally delete all file uploads, avatars, and custom emoji on a Zulip server (across all organizations) with the following command:

rm -rf /home/zulip/uploads/*/*

If you're hosting multiple organizations and would like to remove uploads from a single organization, you'll need to access realm.id in the management shell before deleting the organization from the database (this will be 2 for the first organization created on a Zulip server, shown in the example below), e.g.:

rm -rf /home/zulip/uploads/*/2/

Once that's done, you can simply re-run the import process.