- Running Redis on the application server
- Setting up a Redis-only server
- Increasing the number of Redis connections beyond the default
- Tuning the TCP stack for Redis
- Running with multiple Redis instances
- Redis Sentinel
- Setting the Redis Cache instance as an LRU
- Using a Redis HA setup
- Using Secure Sockets Layer (SSL)
- Renamed commands
- SSL certificates
- Lazy freeing
- Common Troubleshooting
Configuring Redis
Running Redis on the application server
Using an alternate local Redis Instance
Omnibus GitLab provides an instance of Redis by default. Administrators who
wish to point the GitLab application at their own locally running Redis
instance should make the following changes in gitlab.rb
. Run
gitlab-ctl reconfigure
for the changes to take effect.
redis['enable'] = false
# Redis via TCP
gitlab_rails['redis_host'] = '127.0.0.1'
gitlab_rails['redis_port'] = 6379
# OR Redis via Unix domain sockets
gitlab_rails['redis_socket'] = '/tmp/redis.sock' # defaults to /var/opt/gitlab/redis/redis.socket
# Password to Authenticate to alternate local Redis if required
gitlab_rails['redis_password'] = 'Redis Password'
Making a bundled Redis instance reachable via TCP
Use the following settings if you want to make one of the Redis instances managed by Omnibus GitLab reachable via TCP.
redis['port'] = 6379
redis['bind'] = '127.0.0.1'
Setting up a Redis-only server
If you’d like to setup a separate Redis server (e.g. in the case of scaling issues) for use with GitLab you can do so using Omnibus GitLab.
Setting up the Redis Node
Note: Redis does not require authentication by default. See Redis Security documentation for more information. We recommend using a combination of a Redis password and tight firewall rules to secure your Redis service.
- Download/install Omnibus GitLab using steps 1 and 2 from GitLab downloads. Do not complete other steps on the download page.
-
Create/edit
/etc/gitlab/gitlab.rb
and use the following configuration.# Disable all services except Redis redis_master_role['enable'] = true # Redis configuration redis['port'] = 6379 redis['bind'] = '0.0.0.0' # If you wish to use Redis authentication (recommended) redis['password'] = 'Redis Password' # Disable automatic database migrations # Only the primary GitLab application server should handle migrations gitlab_rails['auto_migrate'] = false
Note: The
redis_master_role['enable']
option is only available as of GitLab 8.14, seegitlab_rails.rb
to understand which services are automatically disabled via that option. - Run
sudo gitlab-ctl reconfigure
to install and configure Redis.
Configuring the GitLab Application Node
-
The following settings point the GitLab application at the external Redis service:
redis['enable'] = false gitlab_rails['redis_host'] = 'redis.example.com' gitlab_rails['redis_port'] = 6379 # Required if Redis authentication is configured on the Redis node gitlab_rails['redis_password'] = 'Redis Password'
-
Run
sudo gitlab-ctl reconfigure
to configure the application to use the external Redis node.
Using Google Cloud Memorystore
Google Cloud Memorystore does not support the Redis CLIENT
command.
By default Sidekiq will attempt to set the CLIENT
for debugging
purposes. This can be disabled via this configuration setting:
gitlab_rails['redis_enable_client'] = false
Increasing the number of Redis connections beyond the default
By default Redis will only accept 10,000 client connections. If you need
more that 10,000 connections set the maxclients
attribute to suit your needs.
Be advised that adjusting the maxclients
attribute means that you will also need
to take into account your systems settings for fs.file-max
(for example sysctl -w fs.file-max=20000
)
redis['maxclients'] = 20000
Tuning the TCP stack for Redis
The following settings are to enable a more performant Redis server instance. tcp_timeout
is
a value set in seconds that the Redis server waits before terminating an idle TCP connection.
The tcp_keepalive
is a tunable setting in seconds to TCP ACKs to clients in absence of
communication.
redis['tcp_timeout'] = "60"
redis['tcp_keepalive'] = "300"
Running with multiple Redis instances
GitLab includes support for running with separate Redis instances for different persistence classes, currently: cache
, queues
, shared_state
and actioncable
.
Instance | Purpose |
---|---|
cache
| Store cached data |
queues
| Store Sidekiq background jobs |
shared_state
| Store session-related and other persistent data |
actioncable
| Pub/Sub queue backend for ActionCable |
- Create a dedicated instance for each persistence class as per the instructions in Setting up a Redis-only server
-
Set the appropriate variable in
/etc/gitlab/gitlab.rb
for each instance you are using:gitlab_rails['redis_cache_instance'] = REDIS_CACHE_URL gitlab_rails['redis_queues_instance'] = REDIS_QUEUES_URL gitlab_rails['redis_shared_state_instance'] = REDIS_SHARED_STATE_URL gitlab_rails['redis_actioncable_instance'] = REDIS_ACTIONCABLE_URL
Note: Redis URLs should be in the format:
redis://PASSWORD@REDIS_HOST:PORT/2
Where:
- PASSWORD is the plaintext password for the Redis instance
- REDIS_HOST is the hostname or IP address of the host
- REDIS_PORT is the port Redis is listening on, the default is 6379
- Run
gitlab-ctl reconfigure
Redis Sentinel
For details on configuring Redis Sentinel, see https://docs.gitlab.com/ee/administration/high_availability/redis.html.
Setting the Redis Cache instance as an LRU
Using multiple Redis instances allows you to configure Redis as a Least Recently Used cache. Note you should only do this for the Redis cache instance; the Redis queues and shared state instances should never be configured as an LRU, since they contain data (e.g. Sidekiq jobs) that is expected to be persistent.
To cap memory usage at 32GB, you can use:
redis['maxmemory'] = "32gb"
redis['maxmemory_policy'] = "allkeys-lru"
redis['maxmemory_samples'] = 5
Using a Redis HA setup
See https://docs.gitlab.com/ee/administration/high_availability/redis.html.
Using Secure Sockets Layer (SSL)
Redis v3.2.x does NOT support SSL out of the box. However, you can encrypt a Redis connection using stunnel. AWS ElasticCache also supports Redis over SSL.
Renamed commands
By default, the KEYS
command is disabled as a security measure.
If you’d like to obfuscate or disable this command, or other commands, edit the redis['rename_commands']
setting in /etc/gitlab/gitlab.rb
to look like:
redis['rename_commands'] = {
'KEYS': '',
'OTHER_COMMAND': 'VALUE'
}
-
OTHER_COMMAND
is the command you want to modify -
VALUE
should be one of:- A new command name.
- ’’, which completely disables the command
To disable this functionality:
- Set
redis['rename_commands'] = {}
in your/etc/gitlab/gitlab.rb
file - Run
sudo gitlab-ctl reconfigure
Limitations
-
GitLab does NOT ship with stunnel or other tools to provide encryption for the Redis server. However, GitLab does provide client support via the
rediss://
(as opposed toredis://
) URL scheme. -
Redis Sentinel does NOT support SSL yet. If you use Redis Sentinel, do not activate client support for SSL. This pull request may bring native support to Redis 6.0.
Activating SSL (client settings)
To activate GitLab client support for SSL, do the following:
-
Add the following line to
/etc/gitlab/gitlab.rb
:gitlab_rails['redis_ssl'] = true
-
Run
sudo gitlab-ctl reconfigure
for the changes to take effect.
SSL certificates
If you are using custom SSL certificates for Redis, be sure to add them to the trusted certificates.
Lazy freeing
Redis 4 introduced lazy freeing. This can improve performance when freeing large values.
This setting defaults to false
. To enable it, you can use:
redis['lazyfree_lazy_eviction'] = true
redis['lazyfree_lazy_expire'] = true
redis['lazyfree_lazy_server_del'] = true
redis['replica_lazy_flush'] = true
Common Troubleshooting
x509: certificate signed by unknown authority
This error message suggests that the SSL certificates have not been properly added to the list of trusted certificates for the server. To check whether this is an issue:
-
Check Workhorse logs in
/var/log/gitlab/gitlab-workhorse/current
. -
If you see messages that look like:
2018-11-14_05:52:16.71123 time="2018-11-14T05:52:16Z" level=info msg="redis: dialing" address="redis-server:6379" scheme=rediss 2018-11-14_05:52:16.74397 time="2018-11-14T05:52:16Z" level=error msg="unknown error" error="keywatcher: x509: certificate signed by unknown authority"
The first line should show
rediss
as the scheme with the address of the Redis server. The second line indicates the certificate is not properly trusted on this server. See the previous section. -
Verify that the SSL certificate is working via these troubleshooting steps.
NOAUTH Authentication required
A Redis server may require a password sent via an AUTH
message before
commands are accepted. A NOAUTH Authentication required
error message
suggests the client is not sending a password. GitLab logs may help
troubleshoot this error:
-
Check Workhorse logs in
/var/log/gitlab/gitlab-workhorse/current
. -
If you see messages that look like:
2018-11-14_06:18:43.81636 time="2018-11-14T06:18:43Z" level=info msg="redis: dialing" address="redis-server:6379" scheme=rediss 2018-11-14_06:18:43.86929 time="2018-11-14T06:18:43Z" level=error msg="unknown error" error="keywatcher: pubsub receive: NOAUTH Authentication required."
-
Check that the Redis client password specified in
/etc/gitlab/gitlab.rb
is correct:gitlab_rails['redis_password'] = 'your-password-here'
-
If you are using the Omnibus-provided Redis server, check that the server has the same password:
redis['password'] = 'your-password-here'
Redis connection reset (ECONNRESET)
If you see Redis::ConnectionError: Connection lost (ECONNRESET)
in the
GitLab Rails logs (/var/log/gitlab-rails/production.log
), this might
indicate that the server is expecting SSL but the client is not
configured to use it.
-
Check that the server is actually listening to the port via SSL. For example:
/opt/gitlab/embedded/bin/openssl s_client -connect redis-server:6379
-
Check
/var/opt/gitlab/gitlab-rails/etc/resque.yml
. You should see something like:production: url: rediss://:mypassword@redis-server:6379/
-
If
redis://
is present instead ofrediss://
, theredis_ssl
parameter may not have been configured properly, or the reconfigure step may not have been run.
Connecting to Redis via the CLI
When connecting to Redis for troubleshooting you can use:
-
Redis via Unix domain sockets:
/opt/gitlab/embedded/bin/redis-cli -s /var/opt/gitlab/redis/redis.socket
-
Redis via TCP:
/opt/gitlab/embedded/bin/redis-cli -h 127.0.0.1 -p 6379
-
Password to authenticate to Redis if required:
/opt/gitlab/embedded/bin/redis-cli -h 127.0.0.1 -p 6379 -a <password>