This article provides migration instructions to replace CentOS 7 instances with Red Hat Enterprise Linux 9 (RHEL 9). The enrollment and provisioning of new App Connectors can be automated in a few steps using Terraform (IaC) or Container Orchestration to further simplify deployment.

Note the following requirements for successfully migrating from CentOS 7 to RHEL 9:

• Use a fresh install for all deployments.
• The EL9 repository must be used with RHEL 9 base OS. Older platform binaries (EL7/EL8) are not supported.
• Ensure that the/opt/zscaler/var folder is empty before install.
• Yum upgrades from EL7/EL8 to RHEL9 are not supported.

Use the following steps to migrate from CentOS 7 to RHEL 9:

1. Create new App Connector groups and provisioning keys for each location.

Do not reuse existing provisioning keys as this will add the new RHEL 9 App Connectors to the old App Connector groups. Mixing different host OS and Zscaler software versions in a single group is not supported.

3. (Optional) If you have old App Connectors (el7/el8), use the following commands before clearing the contents of /opt/zscaler/var/

   # systemctl stop zpa-connector
   # yum remove zpa-connector
   # rm -rf /opt/zscaler/var/*

4. Follow the step-by-step guide to deploy new VMs using the RHEL 9 images and newly created provisioning keys. Ensure the yum repository is pointing to the new RHEL 9 link: https://yum.private.zscaler.com/yum/el9

Only RHEL 9 repositories and RPMs are supported on RHEL 9.

5. Add the new App Connector groups to each respective server group.

   

6. (Optional) Disable the App Connector groups 5 minutes prior to the regional off-hours maintenance window to allow connections to gradually drain down.

7. During regional off hours, remove the CentOS 7 App Connector groups.