yontalcar / linux-system-roles-network

An ansible role to configure networking

linux-system-roles/network

This role enables users to configure network on target machines. The role can be used to configure:

• Ethernet interfaces
• Bridge interfaces
• Bonded interfaces
• VLAN interfaces
• MacVLAN interfaces
• Infiniband interfaces
• IP configuration

General

The role supports two providers: nm and initscripts. The provider can be configured per host via the network_provider variable. In absence of explicit configuration, it is autodetected based on the distribution. The nm provider is used by default on RHEL7 and initscripts on RHEL6. However, note that the provider is not tied to a certain distribution, given that the required API is available. For nm this means that at least version 1.2 of NetworkManager's API is available. For initscripts, it requires the legacy network service as commonly available on Fedora/RHEL.

For each host a list of networking profiles can be configured via the network_connections variable.

• For initscripts, profiles correspond to ifcfg files in /etc/sysconfig/network-scripts/ifcfg-*.

• For NetworkManager, profiles correspond to connection profiles as handled by NetworkManager. Fedora and RHEL use the rh-plugin for NetworkManager which also writes configuration files to /etc/sysconfig/network-scripts/ifcfg-* for compatibility.

Note that the role primarily operates on networking profiles (connections) and not on devices but it defaults to use the profile name as the interface name. But it is also possible to create generic profiles, by creating for example a profile with a certain IP configuration without activating the profile. To apply the configuration to the actual networking interface, a command like nmcli needs to be used on the target system.

Warning

The role updates or creates all connection profiles on the target system as specified in the network_connections variable. Therefore, the role will remove settings from the specified profiles if the settings are only present on the system but not in the network_connections variable. The following exceptions apply:

• For profiles that only contain a state setting, the role will only activate or deactivate the connection without changing its configuration.

• The route_append_only setting allows to only add new routes to the existing routes on the system.

• The rule_append_only setting allows to preserve the current routing rules. There is no support to specify routing rules at the moment.

See also Limitations.

Variables

The role is configured via variables with a network_ name prefix. The connection profiles are configured as network_connections, which is a list of dictionaries that have a name.

name

The name identifies the connection profile. It is not the name of the networking interface for which the profile applies, though it makes sense to restrict the profile to an interface and give them the same name. Note also that you can have multiple profiles for the same device, but of course only one profile can be active on the device at each time. Note that for NetworkManager, a connection can only be active at one device at a time.

• For NetworkManager, the name translates to connection.id. Altough NetworkManager supports multiple connections with the same connection.id, this role cannot handle a duplicate name. Specifying a name multiple times refers to the same connection profile.

• For initscripts, the name determines the ifcfg file name /etc/sysconfig/network-scripts/ifcfg-$NAME. Note that here too the name doesn't specify the DEVICE but a filename. As a consequence '/' is not a valid character for the name.

state and persistent_state

Each connection profile can have a runtime state, represented by the state setting and a persistent state, represtented by the persistent_state setting.

The optional state setting supports the following values:

• up
• down

It defines whether the profile is activated (up) or deactivated (down). If it is unset, the profile's runtime state will not be changed.

The persistent_state setting is either present (default) or absent. If the persistent_state setting is present and the connection profile contains a type setting, the profile will be created or updated. If the profile is incomplete (lacks the type setting) and persistent_state is present, the behavior is undefined. The value absent makes the role ensure that the profile is not present on the target host.

Example

network_connections:
  - name: eth0
    persistent_state: absent

Above example ensures the absence of a connection profile. If a profile with name eth0 exists, it will be deleted.

• For NetworkManager this deletes all connection profiles with the matching connection.id. Deleting a profile usually does not change the current networking configuration, unless the profile was currently activated on a device. In that case deleting the currently active connection profile disconnects the device. That makes the device eligible to autoconnect another connection (see also rh#1401515).

• For initscripts it results in the deletion of the ifcfg file. Usually that has no side-effect, unless some component is watching the sysconfig directory.

Example

network_connections:
  - name: eth0
    #persistent_state: present  # default
    type: ethernet
    autoconnect: yes
    mac: 00:00:5e:00:53:5d
    ip:
      dhcp4: yes

Above example creates a new connection profile or ensures that it is present with the given configuration. It implies the persistent_state setting to be present.

Valid values for type are:

• bond
• bridge
• ethernet
• infiniband
• macvlan
• team
• vlan

The value present for the persistent_state setting does not directly result in a change in the network configuration. That is, without state set to up, the profile is only created or modified, not activated.

• For NetworkManager, note the new connection profile is created with autoconnect turned on by default. Thus, NetworkManager may very well decide right away to activate the new profile on a currently disconnected device. (rh#1401515).

autoconnect

By default, profiles are created with autoconnect enabled.

• For NetworkManager, this translates to the connection.autoconnect property.

• For initscripts, this corresponds to the ONBOOT property.

mac

The mac address is optional and restricts the profile to be usable only on devices with the given MAC address. mac is only allowed for type ethernet or type infiniband to match a non-virtual device with the profile.

• For NetworkManager mac is the permanent MAC address ethernet.mac-address.

• For initscripts, this means the currently configured MAC address of the device (HWADDR).

interface_name

For the types ethernet and infiniband, this option restricts the profile to the given interface by name. This argument is optional and by default the profile name is used unless a mac address is specified using the mac key. Specifying an empty string ("") allows to specify that the profile is not restricted to a network interface.

Note: With persistent interface naming, the interface is predictable based on the hardware configuration. Otherwise, the mac address might be an option.

For virtual interface types like bridges, this argument is the name of the created interface. In case of a missing interface_name, the profile name name is used.

Note: The profile name name and the device name interface_name may be different or the profile may not be tied to an interface at all.

zone

Sets the firewalld zone for the interface.

Slaves to bridge/bond/team devices cannot specify a zone.

state: up

Example

network_connections:
  - name: eth0
    state: up

The above example requires an existing profile to activate.

• For NetworkManager this results in nmcli connection id {{name}} up.

• For initscripts it is the same as ifup {{name}}.

State up also supports an optional integer setting wait. wait: 0 will only initiate the activation but not wait until the device is fully connected. Connection will complete in the background, for example after a DHCP lease was received. wait: <SECONDS> is a timeout for how long we give the device to activate. The default is using a suitable timeout. Note that this setting is only supported by NetworkManager. TODO wait different from zero is not yet implemented.

Note that state up always re-activates the profile and possibly changes the networking configuration, even if the profile was already active before. As such, it always changes the system.

state: down

Example

network_connections:
  - name: eth0
    state: down

Another state is down.

• For NetworkManager it is like calling nmcli connection id {{name}} down.

• For initscripts this means to call ifdown {{name}}.

This is the opposite of the up state. It also will always issue the command to deactivate the profile, even it if seemingly is currently not active. As such, down always changes the system.

For NetworkManager, a wait argument is supported like for up state.

Refer to the same connection multiple times

Example

network_connections:
  - name: Wired0
    type: ethernet
    interface_name: eth0
    ip:
      dhcp4: yes

  - name: Wired0
    state: up

As said, the name identifies a unique profile. However, you can refer to the same profile multiple times. Therefore it is possible to create a profile and activate it separately.

ip

The IP configuration supports the following options:

network_connections:
  - name: eth0
    type: ethernet
    ip:
      route_metric4: 100
      dhcp4: no
      #dhcp4_send_hostname: no
      gateway4: 192.0.2.1

      dns:
        - 192.0.2.2
        - 198.51.100.5
      dns_search:
        - example.com
        - subdomain.example.com

      route_metric6: -1
      auto6: no
      gateway6: 2001:db8::1

      address:
        - 192.0.2.3/24
        - 198.51.100.3/26
        - 2001:db8::80/7

      route:
        - network: 198.51.100.128
          prefix: 26
          gateway: 198.51.100.1
          metric: 2
        - network: 198.51.100.64
          prefix: 26
          gateway: 198.51.100.6
          metric: 4
      route_append_only: no
      rule_append_only: yes

Manual addressing can be specified via a list of addresses and prefixes address. Also, manual addressing can be combined with either dhcp4 and auto6 for DHCPv4 and SLAAC. The dhcp4 and auto6 keys can be omitted and the default depends on the presence of manual addresses.

If dhcp4 is enabled, it can be configured whether the DHCPv4 request includes the hostname via dhcp4_send_hostname. Note that dhcp4_send_hostname is only supported by the nm provider and translates to ipv4.dhcp-send-hostname property.

Manual DNS configuration can be specified via a list of addresses given in the dns option and a list of domains to search given in the dns_search option.

• For NetworkManager, route_metric4 and route_metric6 corresponds to the ipv4.route-metric and ipv6.route-metric properties, respectively. If specified, it determines the route metric for DHCP assigned routes and the default route, and thus the priority for multiple interfaces.

Static route configuration can be specified via a list of routes given in the route option. The default value is an empty list. Each route is a dictionary with the following entries: network, prefix, gateway and metric. network and prefix together specify the destination network. CIDR notation or network mask notation are not supported yet. If the boolean option route_append_only is yes, the specified routes are appended to the existing routes, if it is no (default), the current routes are replaced. Setting this option to yes without setting route has the effect of preserving the current static routes. The boolean option rule_append_only works in a similar way for routing rules. Note that there is no further support for routing rules at the moment, so this option serves merely the purpose of preserving the current routing rules. Note also that when route_append_only/rule_append_only is not specified, the current routes/routing rules will be deleted by the role.

Slaves to bridge/bond/team devices cannot specify ip settings.

type: ethernet

Ethernet-specific options can be set using the connection profile variable ethernet. This variable should be specified as a dictionary with the following items (options): autoneg, speed and duplex, which correspond to the settings of the ethtool utility with the same name. speed is an integer giving the speed in Mb/s, the valid values of duplex are half and full, and autoneg accepts a boolean value (default is yes) to configure autonegotiation. The speed and duplex settings are required when autonegotiation is disabled.

network_connections:
  - name: eth0
    type: ethernet

    ethernet:
      autoneg: no
      speed: 1000
      duplex: full

Virtual types and Slaves

Device types like bridge, bond, team work similar:

network_connections:
  - name: br0
    type: bridge
    #interface_name: br0  # defaults to the connection name

Note that team is not supported on RHEL6 kernels.

For slaves of these virtual types, the special properites slave_type and master must be set. Also note that slaves cannot have ip settings.

network_connections:
  - name: internal-br0
    interface_name: br0
    type: bridge
    ip:
      dhcp4: no
      auto6: no

  - name: br0-bond0
    type: bond
    interface_name: bond0
    master: internal-br0
    slave_type: bridge

  - name: br0-bond0-eth1
    type: ethernet
    interface_name: eth1
    master: br0-bond0
    slave_type: bond

Note that the master refers to the name of a profile in the ansible playbook. That is, it is neither an interface-name, nor a connection-id of NetworkManager.

• For NetworkManager, master will be converted to the connection.uuid of the corresponding profile.

• For initscripts, the master is looked up as the DEVICE from the corresponding ifcfg file.

As master refers to other profiles of the same or another play, the order of the connections list matters. Also, --check ignores the value of the master and assumes it will be present during a real run. That means, in presence of an invalid master, --check may signal success but the actual play run fails.

type: vlan

VLANs work too:

network_connections:
  - name: eth1-profile
    autoconnet: no
    type: ethernet
    interface_name: eth1
    ip:
      dhcp4: no
      auto6: no

  - name: eth1.6
    autoconnect: no
    type: vlan
    parent: eth1-profile
    vlan:
      id: 6
    ip:
      address:
        - 192.0.2.5/24
      auto6: no

Like for master, the parent references the connection profile in the ansible role.

type: macvlan

MACVLANs also work:

network_connections:
  - name: eth0-profile
    type: ethernet
    interface_name: eth0
    ip:
      address:
        - 192.168.0.1/24

  - name: veth0
    type: macvlan
    parent: eth0-profile
    macvlan:
      mode: bridge
      promiscuous: yes
      tap: no
    ip:
      address:
        - 192.168.1.1/24

Like for master and vlan, the parent references the connection profile in the ansible role.

network_provider

When Network Manager is running on the target system, the role will use the nm provider and initscripts otherwise. The variable network_provider allows to specify a specific provider. Setting it to network_provider_os_default will choose the provider depening on the operating system. This is usually nm except for RHEL 6 or CentOS 6 systems.

Example

network_provider: nm
network_connections:
  - name: eth0
    #...

Limitations

Configure over the Network

Ansible usually works via the network, for example via SSH. This role doesn't answer how to bootstrap networking configuration. One option may be ansible-pull. Another to initially auto-configure the host during installation (ISO based, kickstart, etc.), so that the host is connected to a management LAN or VLAN. It strongly depends on your environment.

• For initscripts provider, deploying a profile merely means to create the ifcfg files. Nothing happening automatically until the play issues ifup or ifdown via the up or down states -- unless of course, there are other components that watch the ifcfg files and react on changes.

• The initscripts provider requires the different profiles to be in the right order when they depend on each other, for example the bonding master device needs to be specified before the slave devices.

• When removing a profile for NetworkManager it will also take the connection down and possibly remove virtual interfaces. With the initscripts provider removing a profile does not change its current runtime state (this is going to be the case for NetworkManager in the future, too.).

• For NetworkManager, modifying a connection with autoconnect enabled may result in the activation of the new profile on a previously disconnected interface. Also, deleting a NetworkManager connection that is currently active will tear down the interface. Therefore, the order of the steps may matter and or careful handling of autoconnect property may be necessary. This should be improved in NetworkManager RFE rh#1401515.

• It seems difficult to change networking of the target host in a way that breaks the current SSH connection of ansible. If you want to do that, ansible-pull might be a solution. Alternatively, a combination of async/poll with changing the ansible_host midway of the play. TODO The current role doesn't yet support to easily split the play in a pre-configure step, and a second step to activate the new configuration.

In general, to successfully run the play, one must understand which configuration is active in the first place and then carefully configure a sequence of steps to change to the new configuration. Don't cut off the branch on which you are sitting. The actual solution depends strongly on your environment.

If something goes wrong

When something goes wrong while configuring the networking remotely, you might need to get phyisical access to the machine to recover.

• TODO NetworkManager supports a checkpoint/rollback feature. At the beginning of the play we could create a checkpoint and if we lose connectivity due to an error, NetworkManager would automatically rollback after timeout. The limitations is that this would only work with NetworkManager, and it's not clear that rollback will result in a working configuration either.

Invalid and Wrong Configuration

The role will reject invalid configurations, so it is a good idea to test the role with --check first. There is no protection against wrong (but valid) configuration. Double-check your configuration before applying it.

Compatibility

The role supports the same configuration scheme for both providers. That means, you can use the same playbook with NetworkManager and initscripts. Note however, that not every option is handled exactly the same by every provider. Do a test run first with --check.

It is also not supported to create a configuration for one provider, and expect another provider to handle them. For example, creating proviles with initscripts provider and later enabling NetworkManager is not guaranteed to work automatically. Possibly you have to adjust the configuration so that it can be used by another provider.

For example what will work is to configure a RHEL6 host with initscripts and upgrade to RHEL7 while continuing to use initscripts on RHEL7. What is not guaranteed to work it to upgrade to RHEL7, disable initscripts and expect NetworkManager to take over the configuration automatically.

Depending on NetworkManager's configuration, connections may be stored as ifcfg files as well, but again it is not guaranteed that plain initscripts can handle these ifcfg files after disabling the NetworkManager service.