Distributed Session Cache in Docker environment
The Distributed Session Cache (DSC) is an independent service that acts as a centralized session repository for a web reverse proxy server environment. Servers in the environment can use the DSC to provide failover for user sessions.
When ISAM is running in a Docker environment, we can use the DSC Configuration page of the LMI to configure the DSC. See Manage Distributed Session Cache in Docker.
To configure a web reverse proxy instance to use the DSC, go to Web > Manage > Reverse Proxy and select to edit the instance. On the Session tab, select the Enable Distributed Session Cache option. If we enable the DSC within a web reverse proxy instance but do not want the configuration to be automatically updated if the DSC configuration changes, set the value of the dsess-auto-update entry in the [session] stanza in the WebSEAL configuration file to no.
The SSL certificates used by the DSC are stored in the dsc_key_store key store. This key store is initially populated with a self-signed certificate used when connecting to the DSC servers. The self-signed certificate can be replaced with a CA-signed certificate using the SSL Certificates management page of the LMI.
To start the DSC container within a Docker environment, specify the Docker environment variables SERVICE = 'dsc' and INSTANCE = '1|2|3|4' at container start time. The instance number corresponds to the role the DSC container will play in the environment (1 corresponds to primary, 2 corresponds to secondary, 3 corresponds to tertiary, 4 corresponds to quaternary). We can configure up to four DSC servers in the environment for high availability of the DSC. See Failover for the distributed session cache.
We can also dynamically update the trace level of a DSC server using the CLI of the DSC container. This can be achieved using the trace CLI command within the dsc menu. Updating the trace level will not cause any down-time of the DSC server. The trace output is available in the dsc.log file, which can be monitored using the monitor CLI command within the isam menu.
Parent topic: Docker support
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