Enable IP address forwarding for a container host

The container management feature in Kyndryl Cloud Uplift has been deprecated and will be disabled on November 30, 2026.
For more details, see Deprecation of Kyndryl Cloud Uplift container management.

IP forwarding is disabled on some versions of Linux, which breaks IP forwarding to containers after the VM is suspended and then resumed.

Affected Linux distributions:

  • CentOS
  • Red Hat Enterprise Linux
  • Fedora
To enable IP forwarding for a container host VM

  1. In the VM, navigate to the directory /usr/lib/systemd/network/

    Create the directory if it doesn’t exist.

  2. Type the following command to determine the name of the Docker interface:

     ifconfig

    Typically, the host name for the Docker interface on a machine where there is only one network interface card installed, is docker0.

  3. Create a new file named: 80-container-<interface_name>.network, where <interface_name> is the host name for the Docker interface that you determined in step 2.

  4. In the new file, add the following content: 
     [Network]
 IPForward=kernel
  5. Restart the VM.
  6. Verify that containers are still accessible after the VM is suspended and then resumed, by typing the following command in a terminal: 
     sysctl net.ipv4.conf.<interface_name>.ip_forward

    The terminal should display the status:

     net.ipv4.ip_forward = 1