Support setting up Open vSwitch (Ovs) Bridge network
    
    Resolves: https://issues.redhat.com/browse/RHEL-33465
    Conflict: C9S misses the following two commits,
              - 1397006 ("dracut-module-setup: Remove remove_cpu_online_rule() since PowerPC uses nr_cpus")
              - 73c9eb7 ("dracut-module-setup: remove old s390 network device config (#1937048)")
    
    Upstream Status: git@github.com:rhkdump/kdump-utils.git
    
    commit 224d3102c54749eae98bfa1af8932aade8e4d2da
    Author: Coiby Xu <coxu@redhat.com>
    Date:   Mon Apr 22 15:02:42 2024 +0800
    
        Support setting up Open vSwitch (Ovs) Bridge network
    
        Resolves: https://issues.redhat.com/browse/RHEL-33465
    
        This patch supports setting up an Ovs bridge in kdump initrd. An Ovs
        bridge is similar to a classic Linux bridge but we use ovs-vsctl to find
        out the Ethernet device (having the MAC address as the bridge) added to
        an Ovs bridge. Once we copy all the needed NetworkManager (NM) connection
        profiles to kdump initrd and all the necessary files, NM will create an Ovs bridge
        automatically in kdump initrd.
    
        In the case of OpenShift Container Platform (OCP),
        ovs-configuration.service [1] is responsible for setting up an Ovs bridge.
        In theory, we can also try to bring up the original physical network
        interface before ovs-configuration.service. But this approach is
        cumbersome because it breaks our assumption that we should bring up the
        same network in kdump intrd as in 1st kernel (establishing the same network
        in kdump initrd only needs to copy the needed NM connection profiles
        thus we don't need to learn how different network setup work under the
        hood).
    
        How to test this patch with the help of configure-ovs.sh?
        =========================================================
    
        1. Extract configure-ovs.sh from [2]
    
        2. Install necessary packages for configure-ovs.sh
            dnf install openvswitch -yq
            dnf install NetworkManager-ovs nmap-ncat -yq
    
            systemctl enable --now openvswitch
    
            # restart NM so the ovs plugin can be activated
            systemctl restart NetworkManager
    
        3. Assume the network interface used for creating an Ovs bridge is
           "ens2", use configure-ovs.sh to create an Ovs bridge,
    
            interface=ens2
            mkdir -p /etc/ovnk
            echo $interface > /etc/ovnk/iface_default_hint
            bash configure-ovs.sh OVNKubernetes
    
        4. (Optional) If you want to make the created Ovs bridge survive a
           reboot, simply make the created NM connections created by
           configure-ovs.sh persist,
    
            cp /run/NetworkManager/system-connections/ovs-* /etc/NetworkManager/system-connections/
    
        If you need to create an Ovs bridge on top of a bonding network, use the
        following commands for step 3,
    
            nmcli con add type bond ifname bond0
            nmcli con add type ethernet ifname eth0 master bond0
            nmcli con add type ethernet ifname eth1 master bond0
    
            echo bond0 > /etc/ovnk/iface_default_hint
            bash configure-ovs.sh OVNKubernetes
    
        Note
        1. For RHEL, openvswitch3.3 may be installed so we need to get the
           package name by "rpm -qf /usr/lib/systemd/system/openvswitch.service"
    
        2. For RHEL9, openvswitch package needs to installed from another repo,
            cat << 'EOF' > /etc/yum.repos.d/ovs.repo
            [rhosp-rhel-9-fdp-cdn]
            name=Red Hat Enterprise Linux Fast Datapath $releasever - $basearch cdn
            baseurl=http://rhsm-pulp.corp.redhat.com/content/dist/layered/rhel9/$basearch/fast-datapath/os/
            enabled=1
            gpgcheck=0
            EOF
    
            dnf install openvswitch3.3 -yq
    
        3.  We instruct ovsdb-server to ignore NM connection files changes by
            "--ovsdb-server-options='--disable-file-column-diff'". In the
            future, this may not be needed if we simply copy all active NM
            connection profiles to kdump initrd without changing them after
            coming up with different solutions for the following cases,
            1. Some environments like some Azure machine doesn't use persistent
               NIC name. Current solution is to modify a NM connection
               profile to match a device by MAC address, for details check
               commit 568623e)
    
            2. If a NIC has an IPv4 or IPv6 address, set the corresponding
               may-fail property to no. Otherwise, dumping vmcore over IPv6
               could fail because only IPv4 network is ready or vice versa. Current
               solution is to disable IPv6 if only IPv4 is used and vice versa,
               for details check commit 9dfcacf,
    
            3. Some NICs need longer connection.wait-device-timeout otherwise
               the connection will fail to be established (commit 6b586a9).
    
        [1] https://github.com/openshift/machine-config-operator/blob/master/templates/common/_base/units/ovs-configuration.service.yaml
        [2] https://github.com/openshift/machine-config-operator/blob/master/templates/common/_base/files/configure-ovs-network.yaml
    
        Signed-off-by: Coiby Xu <coxu@redhat.com>
    
    Signed-off-by: Coiby Xu <coxu@redhat.com>