Troubleshooting: Switching from CNI to Netavark (Podman deployments)

Some older operating systems, such as RHEL 8, running Podman may be configured to use the legacy, deprecated CNI-based plug-in which creates issues for DNS lookups in Concert containers. The Concert installation process is expected to encounter issues, the issue might also surface during the runtime stage. It is advisable to transition to the recommended alternative, i.e., from CNI to Netavark. This is to ensure continued support and avoid potential issues that may arise from using a deprecated CNI-based plug-in. Refer to the following instructions for a workaround by switching to Netavark.

Note: Perform the following steps as a root user.

Step 1: Determine if the CNI plug-in is configured.

Run the following command to determine if your Podman container engine is using the CNI plug-in.

podman info --format {{.Host.NetworkBackend}}

If the response includes cni, then proceed with the following steps as you must switch to the Netavark network backend.

Step 2: Verify the existence of the container configuration file.

Run the following command to verify the existence of the Podman /etc/containers/containers.conf configuration file.

test -f /etc/containers/containers.conf

If the file does not exist, use the following command to copy the default configuration file from /usr/share/containers/containers.conf to /etc/containers/.

cp /usr/share/containers/containers.conf /etc/containers/

If the file already exists (i.e., true), then use the following command to verify the network backend.

grep network_backend /etc/containers/containers.conf

If the network_backend option is set to cni, you must switch to the Netavark network plugin.

Step 2: Install `netavark`.

Run the following command to install the netavark plug-in.

yum install -y netavark

Step 3: Change the backend network in the configuration file.

In the /etc/containers/containers.conf file, change the network_backend field to netavark.

Then, run the following command to validate the change.

grep network_backend /etc/containers/containers.conf

The network_backend option should be set to netavark.

Additionally, the following command should also return netavark in the response.

podman info --format {{.Host.NetworkBackend}}

Step 4: Restart the Podman system.

If a user (root or non-root) already set up Concert, that user must use the following command to reset the Podman system.

podman system reset

Then, run the Concert setup script again. Refer to Installing Concert software on a VM.