Lifecycle Agent Operator (LCA)

The seed image generation requires an existing SNO cluster, referred to as the seed cluster. The SNO cluster must adhere to specific guidelines to be used as a seed cluster; the complete list can be found here.

Some of the guidelines include:

When the LifeCycle Agent Operator runs the seed image generation, the orchestrator performs system configuration validation checks to ensure the required seed SNO configuration is present. If there is any blocking configuration, the relevant information is stored in the SeedGenerator custom resource.

The role of LCA during IBI deployments is limited to generating the seed image used during the final installation. As discussed in future sections, IBI deployments require booting the hardware with a pre-installation iso that leverages the seed image.

The role of LCA during IBU operations includes generating the seed image used during the upgrade, as well as orchestrating the upgrade process itself. This orchestration includes backup and restore operations for cluster configurations and running workloads.

During the upgrade, the LCA orchestrates the process through the following stages:

The diagram below illustrates these stages:

For more detailed information on the stages, refer to the stages of the image-based upgrade in the official documentation.

During the upgrade, LCA can also back up and restore cluster configurations and workloads. Consult the backup and restore guidelines in the official documentation.

The LCA operator cannot manage image-based upgrades at scale. To perform IBU at scale, we utilize another operator, TALM. We will discuss the ImageBasedGroupUpgrade API and how TALM orchestrates such upgrades in the Image-based upgrade for single-node OpenShift clusters section of the lab. The recommended upgrade method for Telco 5G RAN SNOs is the image-based upgrade flow, specifically leveraging the Image Based Group Upgrade (IBGU) CR provided by TALM.