Configuring an SLB

When multiple Always-On Monitoring instances are present, we expect that traffic to these instances is directed through a SLB.

When HA is added to an Always-On Monitoring instance that was configured as a single instance, you need to repopulate the Always-On Monitoring instance's certificates with fresh copies that have the SLB host name in them. For Always-On Monitoring released with Enterprise Manager 13.3, you generate a certificate for the SLB and store that in a wallet by running the emsctl secure command.

  1. Copy the EM key from the Enterprise Manager repository by running the following command:

    emctl config emkey -copy_to_repos

  2. Run emsctl secure.
  3. Restart the Always-On Monitoring instance.
  4. Repeat for all Always-On Monitoring instances already configured.
  5. Make sure to run emctl set property for the emsUrl property to use the newly configured Always-On Monitoring upload URL set up on the SLB. For example: ./emctl set property -name "oracle.sysman.core.events.ems.emsURL" -value "https://<slb hostname>:<slb aom port>/upload"

The URL displayed from emsca and/or emsctl status is the local URL for that Always-On Monitoring instance. In an HA configuration, this local URL is NOT used as the Always-On Monitoring URL, but is used to set up the Always-On Monitoring pool in the SLB. The host and port for each Always-On Monitoring instance is used in the pool with the /upload PUT URL as the target for that pool.

When configuring the SLB, the monitoring URL is the /upload GET URL. This URL returns the string "Always On Monitoring is active."

Note:

Always-on monitoring is supported on F5 from version 11.4.x onwards.