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Manage SSL connectivity

Manage SSL connectivity for your Aiven for Caching service, including enabling secure connections and configuring stunnel for clients without SSL support.

Client support for SSL-encrypted connections

Default support

Aiven for Caching uses SSL encrypted connections by default. This is shown by the use of rediss:// (with double s) prefix in the Service URI on the Aiven Console.


The Service URI is available on the Aiven console.

Since Redis 6, the redis-cli tool itself supports SSL connections; therefore, you can connect directly to your service using:

redis-cli -u rediss://username:password@host:port

Alternatively, you can use the third-party Redli tool:

redli -u rediss://username:password@host:port

Not every Redis client supports SSL-encrypted connections. In such cases, turning off or bypassing SSL is possible but not recommended. Use one of the following options to achieve this.

Set up stunnel process

Set up a stunnel process on the client to manage SSL settings on the database side while hiding it from the client.

Use the following stunnel configuration, for example stunnel.conf, to set up a stunnel process.

client = yes
foreground = yes
debug = info
delay = yes

accept =
connect =
TIMEOUTclose = 0
; For old services only. New ones use Let's Encrypt and there's no
; CA cert available from Aiven console. Most environments trust
; Let's Encrypt by default without any explicit CAfile config.
; CAfile = /path/to/optional/project/cacert/that/you/can/download/from/aiven/console

For details about the global options of the stunnel configuration, see the Stunnel Global Options. More details about setting up such a process are available on the Stunnel website page.

For service-level option, the following parameters are configured:

  • accept => *[host:]port*: Accept connections on the specified address.
  • connect => *[host:]port*: Connect to a remote address.
  • TIMEOUTclose => *seconds*: Time to wait for close_notify.

Adjust settings according to your service. The Overview page lists your Overview > Host and Overview > Port for configuring the connect parameter.

When SSL is in use, HAProxy is responsible for terminating the SSL connections before they get forwarded to Aiven for Caching. This process has a connection timeout set to 12 hours, which is not configurable by users. If you allow long timeouts in Aiven for Caching, this SSL-terminating HAProxy may close the connection before the Aiven for Caching timeout expires. This timeout is independent of the Aiven for Caching timeout.

Allow plain-text connections

An alternative is disable database SSL allowing allow plain-text connections. To allow plain-text connections, you can change this setting on Overview in the Advanced configuration section, or using the Aiven Command Line interface.


Enabling plain-text connections compromises the security of your Aiven for Caching service. Disabling SSL allows potential eavesdroppers to access sensitive credentials and data.

To disable SSL on an existing caching instance, use the following Aiven CLI command substituting <my-caching> with your chosen service name when the service was created.

avn service update <my-Caching> -c "Caching_ssl=false"

After executing the command, the Service URI changes to a new location and starts with the Caching:// prefix (removing the extra 's'), indicating a direct connection to the Aiven for Caching service that does not use SSL.