zulip/docs/production/system-configuration.md

System configuration

The file /etc/zulip/zulip.conf is an INI format configuration file used to configure properties of the system and deployment; /etc/zulip/settings.py is used to configure the application itself. The zulip.conf sections and settings are described below. Changes to zulip.conf generally do not take effect until you run zulip-puppet-apply as root:

# /home/zulip/deployments/current/scripts/zulip-puppet-apply

The zulip-puppet-apply command will display the configuration changes it will make and prompt for you to confirm you'd like to make those changes, before executing them (if you approve).

Truthy values

When a setting refers to "set to true" or "set to false", the values true and false are canonical, but any of the following values will be considered "true", case-insensitively:

• 1
• y
• t
• yes
• true
• enable
• enabled

Any other value (including the empty string) is considered false.

[machine]

puppet_classes

A comma-separated list of the Puppet classes to install on the server. The most common is zulip::profile::standalone, used for a stand-alone single-host deployment. Components of that include:

• zulip::profile::app_frontend
• zulip::profile::memcached
• zulip::profile::postgresql
• zulip::profile::rabbitmq
• zulip::profile::redis
• zulip::profile::smokescreen

If you are using a Apache as a single-sign-on authenticator, you will need to add zulip::apache_sso to the list.

pgroonga

Set to true if enabling the multi-language PGroonga search extension.

timesync

What time synchronization daemon to use; defaults to chrony, but also supports ntpd and none. Installations should not adjust this unless they are aligning with a fleet-wide standard of ntpd. none is only reasonable in containers like LXC which do not allow adjustment of the clock; a Zulip server will not function correctly without an accurate clock.

[deployment]

deploy_options

Options passed by upgrade-zulip and upgrade-zulip-from-git into upgrade-zulip-stage-2. These might be any of:

• --skip-puppet skips doing Puppet/apt upgrades. The user will need to run zulip-puppet-apply manually after the upgrade.
• --skip-migrations skips running database migrations. The user will need to run ./manage.py migrate manually after the upgrade.
• --skip-purge-old-deployments skips purging old deployments; without it, only deployments with the last two weeks are kept.

Generally installations will not want to set any of these options; the --skip-* options are primarily useful for reducing upgrade downtime for servers that are upgraded frequently by core Zulip developers.

git_repo_url

Default repository URL used when upgrading from a Git repository.

[application_server]

http_only

If set to true, [configures Zulip to allow HTTP access][using-http]; use if Zulip is deployed behind a reverse proxy that is handling SSL/TLS termination.

nginx_listen_port

Set to the port number if you prefer to listen on a port other than 443.

nginx_worker_connections

Adjust the worker_connections setting in the nginx server. This defaults to 10000; increasing it allows more concurrent connections per CPU core, at the cost of more memory consumed by NGINX. This number, times the number of CPU cores, should be more than twice the concurrent number of users.

queue_workers_multiprocess

By default, Zulip automatically detects whether the system has enough memory to run Zulip queue processors in the higher-throughput but more multiprocess mode (or to save 1.5GiB of RAM with the multithreaded mode). The calculation is based on whether the system has enough memory (currently 3.5GiB) to run a single-server Zulip installation in the multiprocess mode.

Set explicitly to true or false to override the automatic calculation. This override is useful both Docker systems (where the above algorithm might see the host's memory, not the container's) and/or when using remote servers for postgres, memcached, redis, and RabbitMQ.

rolling_restart

If set to true, when using ./scripts/restart-server to restart Zulip, restart the uwsgi processes one-at-a-time, instead of all at once. This decreases the number of 502's served to clients, at the cost of slightly increased memory usage, and the possibility that different requests will be served by different versions of the code.

service_file_descriptor_limit

The number of file descriptors which Supervisor is configured to allow processes to use; defaults to 40000. If your Zulip deployment is very large (hundreds of thousands of concurrent users), your Django processes hit this limit and refuse connections to clients. Raising it above this default may require changing system-level limits, particularly if you are using a virtualized environment (e.g., Docker, or Proxmox LXC).

s3_memory_cache_size

Used only when the S3 storage backend is in use. Controls the in-memory size of the cache index; the default is 1MB, which is enough to store about 8 thousand entries.

s3_disk_cache_size

Used only when the S3 storage backend is in use. Controls the on-disk size of the cache contents; the default is 200MB.

s3_cache_inactive_time

Used only when the S3 storage backend is in use. Controls the longest amount of time an entry will be cached since last use; the default is 30 days. Since the contents of the cache are immutable, this serves only as a potential additional limit on the size of the contents on disk; s3_disk_cache_size is expected to be the primary control for cache sizing.

thumbnail_workers

How many image-thumbnailing workers to run. Defaults to 1; adding more workers can prevent the image-thumbnailing queue backlogging when large numbers of very large image files are uploaded at once. (When backlogged, image previews for images that have not yet been thumbnailed will appear as loading spinners).

nameserver

When the S3 storage backend is in use, downloads from S3 are proxied from nginx, whose configuration requires an explicit value of a DNS nameserver to resolve the S3 server's hostname. Zulip defaults to using the resolver found in /etc/resolv.conf; this setting overrides any value found there.

uwsgi_listen_backlog_limit

Override the default uwsgi backlog of 128 connections.

uwsgi_processes

Override the default uwsgi (Django) process count. It defaults to a sliding scale between 3 workers for hosts with under 3GB RAM, up to 16 workers for hosts with more than 24GB of RAM.

access_log_retention_days

Number of days of access logs to keep, for both nginx and the application. Defaults to 14 days.

katex_server

Set to a false value to disable the separate service for rendering math with LaTeX. Disabling this service will save a small amount of memory, at the cost of making math blocks significantly slower to render, to the point that using dozens of them in a single message may cause the message to fail to send.

katex_server_port

Set to the port number for the KaTeX server; defaults to port 9700.

[postfix]

mailname

The hostname that Postfix should be configured to receive mail at, as well as identify itself as for outgoing email.

[postgresql]

effective_io_concurrency

Override PostgreSQL's effective_io_concurrency setting.

listen_addresses

Override PostgreSQL's listen_addresses setting.

random_page_cost

Override PostgreSQL's random_page_cost setting

replication_primary

On the warm standby replicas, set to the hostname of the primary PostgreSQL server that streaming replication should be done from.

replication_user

On the warm standby replicas, set to the username that the host should authenticate to the primary PostgreSQL server as, for streaming replication. Authentication will be done based on the pg_hba.conf file; if you are using password authentication, you can set a postgresql_replication_password secret for authentication.

skip_backups

If set to as true value, inhibits the nightly [wal-g backups][wal-g] which would be taken on all non-replicated hosts and all warm standby replicas. This is generally only set if you have multiple warm standby replicas, in order to avoid taking multiple backups, one per replica.

backups_disk_concurrency

Number of concurrent disk reads to use when taking backups. Defaults to 1; you may wish to increase this if you are taking backups on a replica, so can afford to affect other disk I/O, and have an SSD which is good at parallel random reads.

backups_directory

If S3 secrets are not configured, perform daily database backups to this path on disk instead. It should be owned by the postgres user.

This option is not recommended for disaster recovery purposes, since unless the directory is on a different disk from the database itself, backups will likely also be lost if the database is lost. This setting can be useful if the path is on a NAS mountpoint, or if some other process copies this data off the disk; or if backups are purely for point-in-time historical analysis of recent application-level data changes.

backups_incremental

The number of delta (incremental) database backups to take between full backups. Defaults to 0 for S3 backups, and 6 for local-disk backups.

backups_storage_class

What storage class to use when uploading database backups. Defaults to STANDARD, meaning "S3 standard", but many deployments will have overall lower costs if "S3 Standard - Infrequent Access" is used, via the STANDARD_IA value. Also supported is "S3 Reduced Redundancy", by setting REDUCED_REDUNDANCY, but this is not suggested for production use.

backups_compression_method

What compression method to use when storing backups; defaults to lz4, which is fast but does not compress particularly well. Other options are lzma, zstd, and brotl; lzma provides the best (and slowest) compression, while zstd and brotli are middling compromises.

missing_dictionaries

If set to a true value during initial database creation, uses PostgreSQL's standard pg_catalog.english text search configuration, rather than Zulip's improved set of stopwords. Has no effect after initial database construction.

ssl_ca_file

Set to the path to the PEM-encoded certificate authority used to authenticate client connections.

ssl_cert_file

Set to the path to the PEM-encoded public certificate used to secure client connections.

ssl_key_file

Set to the path to the PEM-encoded private key used to secure client connections.

ssl_mode

The mode that should be used to verify the server certificate. The PostgreSQL default is prefer, which provides no security benefit; we strongly suggest setting this to require or better if you are using certificate authentication. See the PostgreSQL documentation for potential values.

version

The version of PostgreSQL that is in use. Do not set by hand; use the PostgreSQL upgrade tool.

[memcached]

memory

Override the number of megabytes of memory that memcached should be configured to consume; defaults to 1/8th of the total server memory.

max_item_size

Override the maximum size that an item in memcached can store. This defaults to 1m; adjusting it should only be necessary if your Zulip server has organizations which have more than 20k users.

size_reporting

Set to a true value to enable object size reporting in memcached. This incurs a small overhead for every store or delete operation, but allows a memcached_exporter to report precise item size distribution.

[loadbalancer]

ips

Comma-separated list of IP addresses or netmasks of external load balancers whose X-Forwarded-For and X-Forwarded-Proto should be respected. These can be individual IP addresses, or CIDR IP address ranges.

[http_proxy]

host

The hostname or IP address of an outgoing HTTP CONNECT proxy. Defaults to localhost if unspecified.

port

The TCP port of the HTTP CONNECT proxy on the host specified above. Defaults to 4750 if unspecified.

listen_address

The IP address that Smokescreen should bind to and listen on. Defaults to 127.0.0.1.

enable_for_camo

Because Camo includes logic to deny access to private subnets, routing its requests through Smokescreen is generally not necessary. Set to true or false to override the default, which uses the proxy only if it is not the default of Smokescreen on a local host.

[sentry]

organization

The Sentry organization used for the Sentry deploy hook.

project

The Sentry project used for the Sentry deploy hook.