Re: [RFC 00/13] reuse NetworkManager connection profiles to set up kdump network

[Kairui Song]

Coiby Xu  于2022年4月2日周六 11:24写道：
> Currently, kexec-tools parses legacy ifcfg-* configuration files or
> NetworkManager .nmconnection connection profiles to build up dracut
> command line parameters like ip=. Then dracut parses these parameters and
> runs nm-initrd-generator to generate NetworkManager connection profiles.
> Taking a bonding network as an example, nm-initrd-generator generates two
> connections as follows,
>   $ /usr/libexec/nm-initrd-generator -s -- bootdev=mybond0 rd.neednet kdumpnic=mybond0 bond=mybond0:kdump-eth0
>
> *** Connection 'mybond0' ***
>
> [connection]
>   id=mybond0
>   uuid=ed87d02b-dd44-4f0e-8b11-37db7e89bb48
>   type=bond
>   autoconnect-retries=1
>   interface-name=mybond0
>   multi-connect=1
>   permissions=
>
> [bond]
>   mode=balance-rr
>
> [ipv4]
>   dhcp-timeout=90
>   dns-search=
>   method=auto
>
> [ipv6]
>   addr-gen-mode=eui64
>   dhcp-timeout=90
>   dns-search=
>   method=auto
>
> [proxy]
>
> *** Connection 'kdump-eth0' ***
>
> [connection]
>   id=kdump-eth0
>   uuid=ed6a7448-b5f8-4f8a-b718-3e24ea1c924b
>   type=ethernet
>   autoconnect-retries=1
>   interface-name=kdump-eth0
>   master=ed87d02b-dd44-4f0e-8b11-37db7e89bb48
>   multi-connect=1
>   permissions=
>   slave-type=bond
>   wait-device-timeout=60000
>
> [ethernet]
>   mac-address-blacklist=
>
> Later dracut starts NetworkManager to activate these profiles to bring up
> the network connections. This way of seting up kdump network is tedious,
> error-prone and unncessary. A better way is to directly copy the needed
> connection profiles to initrd. A potential benefit of this approach for
> the users is they can simply edit the connection profile directly like
> changing ipv4.dhcp-timeout instead of being forced to use the hard-coded
> value enforced by nm-initrd-generator.
>
> This patch set reuses NetworkManager connection profiles to set up kdump
> network. It also reduces the memory consumption of network drivers and
> fix other issues at the same time. Here are the bug list that addressed by
> this patch set on bugzilla,
> Bug 1962421 - [RHEL-9]"eth0: Failed to rename network interface 3 from 'eth0' to 'kdump-eth0': File exists"
> Bug 2064708 - kdump: mkdumprd: failed to make kdump initrd for bridge network on z15 z/vm
>             - bugs related to OOM caused by network driver

Hi Coiby,

This looks great, but one thing I don't understand, how is this going
to help reduce the memory consumption? Shoudn't network drivers be the
same, no matter how they are loaded?
>               - Bug 1950282 - shutdown those unneeded network interfaces to save memory for kdump
>               - Bug 1958587 - the kdump initramfs includes unnecessary NIC drivers for SSH/NFS dumping target
>               - Bug 1890021 - be2net is using too much memory during kdump
>               - Bug 1662202 - [RHEL-8.1] aarch64: hpe-apache crashkernel OOM when dump to network targe
>
> Coiby Xu (13):
>   add function to copy NetworkManage connection profile to the initramfs
>   support legacy ifcfg
>   ask NM to wait the network device to be available
>   don't let NetworkManager manage unneeded network interfaces
>   stop dracut 35network-manager from running nm-initrd-generator
>   set up kdump network bridge by directly copying NM connection profile
>     to initrd
>   set up kdump bonding network by directly copying NM connection profile
>     to initrd
>   fix error for vlan over team network interface
>   set up kdump vlan network by directly copying NM connection profile to
>     initrd
>   set up kdump teaming network by directly copying NM connection profile
>     to initrd
>   clean up unneeded code after copying .nmconnection to initrd
>   address the cases where a NIC has a different name in kdump kernel
>   simplify setup_znet by copying connection profile to initrd
>
> dracut-kdump.sh        |  18 +-
>  dracut-module-setup.sh | 385 ++++++++++++++---------------------------
>  2 files changed, 133 insertions(+), 270 deletions(-)
>
> --
> 2.34.1
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