Upgrading from RHEL 7 to RHEL 8

This section provides step-by-step instructions to upgrade the existing Avi Load Balancer LSC deployments from RHEL 7 to RHEL 8.

Prerequisites

Ensure the following pre-requisites are met before initiating the upgrade:

The Avi Load Balancer Controller/ SE hosts which are being upgraded from RHEL 7.9 to 8.x are of version 21.1.3 or higher.
Docker is in running state until the Avi Load Balancer image is successfully loaded in Podman. It is recommended to not purge or uninstall docker until then.
Extra disk space is required for the Avi Load Balancer Controller (24G)/ SE (12G) images to be successfully loaded in Podman from Docker.

Note:

Rollback from Avi Load Balancer version 21.1.3 is not allowed after upgrading to RHEL 8.x host.

Upgrading the existing Avi Load Balancer LSC Deployments to RHEL 8

To upgrade the Avi Load Balancer LSC deployments from RHEL 7 to RHEL 8,

Stop and disable the Controller/ SE on the host(s) that are being upgraded:
On Controller Hosts:
```
systemctl stop avicontroller
systemctl disable avicontroller
```
On SE Hosts:
```
systemctl stop avise
systemctl disable avise
```
Upgrade from RHEL 7 to RHEL 8 using the steps mentioned here.

Note:
If you are not migrating the Docker Avi Load Balancer images to Podman, do not remove or purge Docker.
After booting in RHEL 8.x, install and upgrade Podman to 3.1.0.
Install the appropriate Kernel version for RHEL 8.x.

Install, enable and start network-scripts on the RHEL 8.x host:

yum install network-scripts
systemctl enable network
systemctl start network

Reboot the host after enabling the Controller/ SE:
On Controller Hosts:
```
systemctl enable avicontroller
```
On SE Hosts:
```
 systemctl enable avise
```

Avi Load Balancer will come up with Podman.

Note:

After upgrading to RHEL 8.x, the host boots up with a default RHEL 8.x kernel which might not be supported or qualified by Avi Load Balancer. In this case, downgrade the Kernel to a supported version.
For Avi Load Balancer upgrades from 21.1.3 to any future version, upload the relevant Avi Load Balancer image only after RHEL OS upgrade is done.

Upgrade Considerations

Starting with Avi Load Balancer version 20.1.3, RHEL versions 8.1, 8.2, 8.3, 8.4 are supported. For instructions to upgrade existing LSC deployments to RHEL 8.x, see Upgrading the existing LSC Deployments to RHEL 8.

Install Jinja2.3 package with Python version two on the Bare Metal hosts.
Install Python version 2 or 3 in the host of the Avi Load Balancer SE.
Recommended and tested Podman version is 3.0.1 with runc container runtime.
When the default FORWARD policy has been set to anything else than ACCEPT, access to containers must be granted in iptables by deploying custom forwarding rules. For more information, click here.
Rollback from 21.1.3 after RHEL 8.x host upgrade is not allowed.