Chapter 12. Setting container network modes
Chapter 12. Setting container network modes The chapter provides information about how to set different network modes. 12.1. Running containers with a static IP The podman run command with the --ip option sets the container network interface to a particular IP address (for example, 10.88.0.44). To verify that you set the IP address correctly, run the podman inspect command. Prerequisites The container-tools meta-package is installed. Procedure Set the container network interface to the IP address 10.88.0.44: Verification Check that the IP address is set properly: 12.2. Running the DHCP plugin for Netavark using systemd Prerequisites The container-tools meta-package is installed. Procedure Enable the DHCP proxy by using the systemd socket: Optional: Display the socket unit file: Create a macvlan network and specify your host interface with it. Typically, it is your external interface: Run the container by using newly created network: Verification Confirm the container has an IP on your local subnet: Inspect the container to verify it uses correct IP addresses: Note When attempting to connect to this IP address, ensure the connection is made from a different host. Connections from the same host are not supported when using macvlan networking. Additional resources Lease dynamic IPs with Netavark 12.3. Running the DHCP plugin for CNI using systemd You can use the systemd unit file to run the dhcp plugin. Prerequisites The container-tools meta-package is installed. Procedure Optional: Make sure you re sign the CNI network stack: Enable the DHCP proxy by using the systemd socket: Optional: Display the socket unit file: Verification Check the status of the socket: 12.4. The macvlan plugin Most of the container images do not have a DHCP client, the dhcp plugin acts as a proxy DHCP client for the containers to interact with a DHCP server. The host system does not have network access to the container. To allow network connections from outside the host to the container, the container has to have an IP on the same network as the host. The macvlan plugin enables you to connect a container to the same network as the host. Note This procedure only applies to rootfull containers. Rootless containers are not able to use the macvlan and dhcp plugins. Note You can create a macvlan network using the podman network create --driver=macvlan command. 12.5. Switching the network stack from CNI to Netavark Previously, containers were able to use DNS only when connected to the single Container Network Interface (CNI) plugin. Netavark is a network stack for containers. You can use Netavark with Podman and other Open Container Initiative (OCI) container management applications. The advanced network stack for Podman is compatible with advanced Docker functionalities. Now, containers in multiple networks access containers on any of those networks. Netavark is capable of the following: Create, manage, and remove network interfaces, including bridge and MACVLAN interfaces. Configure firewall settings, such as network address translation (NAT) and port mapping rules. Support IPv4 and IPv6. Improve support for containers in multiple networks. Warning The CNI network stack is deprecated and will be removed in a future RHEL release. Use the Netavark network stack instead. Prerequisites The container-tools meta-package is installed. Procedure If the /etc/containers/containers.conf file does not exist, copy the /usr/share/containers/containers.conf file to the /etc/containers/ directory: Edit the /etc/containers/containers.conf file, and add the following content to the [network] section: If you have any containers or pods, reset the storage back to the initial state: Reboot the system: Verification Verify that the network stack is changed to Netavark: Note If you are using Podman 4.0.0 or later, use the podman info command to check the network stack setting. Additional resources Podman 4.0's new network stack: What you need to know podman-system-reset man page on your system 12.6. Switching the network stack from Netavark to CNI You can switch the network stack from Netavark to CNI. Warning The CNI network stack is deprecated and will be removed in a future RHEL release. Use the Netavark network stack instead. Prerequisites The container-tools meta-package is installed. Procedure If the /etc/containers/containers.conf file does not exist, copy the /usr/share/containers/containers.conf file to the /etc/containers/ directory: Edit the /etc/containers/containers.conf file, and add the following content to the [network] section: If you have any containers or pods, reset the storage back to the initial state: Reboot the system: Verification Verify that the network stack is changed to CNI: Note If you are using Podman 4.0.0 or later, use the podman info command to check the network stack setting. Additional resources Podman 4.0's new network stack: What you need to know podman-system-reset man page on your system
podman run -d --name=myubi --ip=10.88.0.44 registry.access.redhat.com/ubi9/ubi efde5f0a8c723f70dd5cb5dc3d5039df3b962fae65575b08662e0d5b5f9fbe85 podman inspect --format='{{.NetworkSettings.IPAddress}}' myubi 10.88.0.44 systemctl enable --now netavark-dhcp-proxy.socket Created symlink /etc/systemd/system/sockets.target.wants/netavark-dhcp-proxy.socket /usr/lib/systemd/system/netavark-dhcp-proxy.socket. cat /usr/lib/systemd/system/netavark-dhcp-proxy.socket [Unit] Description=Netavark DHCP proxy socket [Socket] ListenStream=%t/podman/nv-proxy.sock SocketMode=0660 [Install] WantedBy=sockets.target podman network create -d macvlan --interface-name <LAN_INTERFACE> mv1 mv1 podman run --rm --network mv1 -d --name test alpine top 894ae3b6b1081aca2a5d90a9855568eaa533c08a174874be59569d4656f9bc45 podman exec test ip addr 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: eth0@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP qlen 1000 link/ether 5a:30:72:bf:13:76 brd ff:ff:ff:ff:ff:ff inet 192.168.188.36/24 brd 192.168.188.255 scope global eth0 valid_lft forever preferred_lft forever inet6 fe80::5830:72ff:febf:1376/64 scope link valid_lft forever preferred_lft forever podman container inspect test --format {{.NetworkSettings.Networks.mv1.IPAddress}} 192.168.188.36 podman info --format "{{.Host.NetworkBackend}}" cni systemctl enable --now cni-dhcp.socket Created symlink /etc/systemd/system/sockets.target.wants/cni-dhcp.socket /usr/lib/systemd/system/cni-dhcp.socket. cat /usr/lib/systemd/system/io.podman.dhcp.socket [Unit] Description=CNI DHCP service socket Documentation=https://github.com/containernetworking/plugins/tree/master/plugins/ipam/dhcp PartOf=cni-dhcp.service [Socket] ListenStream=/run/cni/dhcp.sock SocketMode=0660 SocketUser=root SocketGroup=root RemoveOnStop=true [Install] WantedBy=sockets.target systemctl status io.podman.dhcp.socket systemctl status cni-dhcp.socket ● cni-dhcp.socket - CNI DHCP service socket Loaded: loaded (/usr/lib/systemd/system/cni-dhcp.socket; enabled; vendor preset: disabled) Active: active (listening) since Mon 2025-01-06 08:39:35 EST; 33s ago Docs: https://github.com/containernetworking/plugins/tree/master/plugins/ipam/dhcp Listen: /run/cni/dhcp.sock (Stream) Tasks: 0 (limit: 11125) Memory: 4.0K CGroup: /system.slice/cni-dhcp.socket cp /usr/share/containers/containers.conf /etc/containers/ network_backend="netavark" podman system reset reboot cat /etc/containers/containers.conf [network] network_backend="netavark" cp /usr/share/containers/containers.conf /etc/containers/ network_backend="cni" podman system reset reboot cat /etc/containers/containers.conf [network] network_backend="cni"