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Chapter 9. Managing a container network

The chapter provides information about how to communicate among containers.

9.1. Listing container networks

In Podman, there are two network behaviors - rootless and rootful:

  • Rootless networking - the network is setup automatically, the container does not have an IP address.
  • Rootful networking - the container has an IP address.

Prerequisites

  • The container-tools module is installed.

Procedure

  • List all networks as a root user: 

    # podman network ls
NETWORK ID    NAME        VERSION     PLUGINS
2f259bab93aa  podman      0.4.0       bridge,portmap,firewall,tuning
    • By default, Podman provides a bridged network.
    • List of networks for a rootless user is the same as for a rootful user.

Additional resources

  • podman-network-ls man page

9.2. Inspecting a network

Display the IP range, enabled plugins, type of network, and so on, for a specified network listed by the podman network ls command.

Prerequisites

  • The container-tools module is installed.

Procedure

  • Inspect the default podman network: 

    $ podman network inspect podman
[
    {
        "cniVersion": "0.4.0",
        "name": "podman",
        "plugins": [
            {
                "bridge": "cni-podman0",
                "hairpinMode": true,
                "ipMasq": true,
                "ipam": {
                    "ranges": [
                        [
                            {
                                "gateway": "10.88.0.1",
                                "subnet": "10.88.0.0/16"
                            }
                        ]
                    ],
                    "routes": [
                        {
                            "dst": "0.0.0.0/0"
                        }
                    ],
                    "type": "host-local"
                },
                "isGateway": true,
                "type": "bridge"
            },
            {
                "capabilities": {
                    "portMappings": true
                },
                "type": "portmap"
            },
            {
                "type": "firewall"
            },
            {
                "type": "tuning"
            }
        ]
    }
]

    You can see the IP range, enabled plugins, type of network, and other network settings.

Additional resources

  • podman-network-inspect man page

9.3. Creating a network

Use the podman network create command to create a new network.

Note

By default, Podman creates an external network. You can create an internal network using the podman network create --internal command. Containers in an internal network can communicate with other containers on the host, but cannot connect to the network outside of the host nor be reached from it.

Prerequisites

  • The container-tools module is installed.

Procedure

  • Create the external network named mynet: 

    # podman network create mynet
/etc/cni/net.d/mynet.conflist

Verification

  • List all networks: 

    # podman network ls
NETWORK ID    NAME        VERSION     PLUGINS
2f259bab93aa  podman      0.4.0       bridge,portmap,firewall,tuning
11c844f95e28  mynet       0.4.0       bridge,portmap,firewall,tuning,dnsname

    You can see the created mynet network and default podman network.

Note

Beginning with Podman 4.0, the DNS plugin is enabled by default if you create a new external network using the podman network create command.

Additional resources

  • podman-network-create man page

9.4. Connecting a container to a network

Use the podman network connect command to connect the container to the network.

Prerequisites

  • The container-tools module is installed.
  • A network has been created using the podman network create command.
  • A container has been created.

Procedure

  • Connect a container named mycontainer to a network named mynet: 

    # podman network connect mynet mycontainer

Verification

  • Verify that the mycontainer is connected to the mynet network: 

    # podman inspect --format='{{.NetworkSettings.Networks}}' mycontainer
map[podman:0xc00042ab40 mynet:0xc00042ac60]

    You can see that mycontainer is connected to mynet and podman networks.

Additional resources

  • podman-network-connect man page

9.5. Disconnecting a container from a network

Use the podman network disconnect command to disconnect the container from the network.

Prerequisites

  • The container-tools module is installed.
  • A network has been created using the podman network create command.
  • A container is connected to a network.

Procedure

  • Disconnect the container named mycontainer from the network named mynet: 

    # podman network disconnect mynet mycontainer

Verification

  • Verify that the mycontainer is disconnected from the mynet network: 

    # podman inspect --format='{{.NetworkSettings.Networks}}' mycontainer
map[podman:0xc000537440]

    You can see that mycontainer is disconnected from the mynet network, mycontainer is only connected to the default podman network.

Additional resources

  • podman-network-disconnect man page

9.6. Removing a network

Use the podman network rm command to remove a specified network.

Prerequisites

  • The container-tools module is installed.

Procedure

  1. List all networks: 

    # podman network ls
NETWORK ID    NAME        VERSION     PLUGINS
2f259bab93aa  podman      0.4.0       bridge,portmap,firewall,tuning
11c844f95e28  mynet       0.4.0       bridge,portmap,firewall,tuning,dnsname

  2. Remove the mynet network: 

    # podman network rm mynet
mynet
Note

If the removed network has associated containers with it, you have to use the podman network rm -f command to delete containers and pods.

Verification

  • Check if mynet network was removed: 

    # podman network ls
NETWORK ID    NAME        VERSION     PLUGINS
2f259bab93aa  podman      0.4.0       bridge,portmap,firewall,tuning

Additional resources

  • podman-network-rm man page

9.7. Removing all unused networks

Use the podman network prune to remove all unused networks. An unused network is a network which has no containers connected to it. The podman network prune command does not remove the default podman network.

Prerequisites

  • The container-tools module is installed.

Procedure

  • Remove all unused networks: 

    # podman network prune
WARNING! This will remove all networks not used by at least one container.
Are you sure you want to continue? [y/N] y

Verification

  • Verify that all networks were removed: 

    # podman network ls
NETWORK ID    NAME        VERSION     PLUGINS
2f259bab93aa  podman      0.4.0       bridge,portmap,firewall,tuning

Additional resources

  • podman-network-prune man page