aws: do not set the primary network interface to "Unmanaged=yes" - #18642
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The file "10-eni-secondary.network" causes systemd-networkd to ignore the secondary ENIs. Before this change, the file found the secondary ENIs by their interface names. The names were correct only if the primary network interface had the name "ens5". But the interface names are different for each instance family and each systemd naming scheme. On Graviton4 instances, the primary network interface has the name "ens34". The file also found this interface. Thus systemd-networkd ignored the primary network interface, and systemd-resolved had no DNS servers for it. On 8th-generation Intel instances, the interfaces have the names "enp39s0" and "enp40s0". The file did not find these interfaces. Thus the secondary ENIs had no protection. With this change, the file finds all the interfaces that use the "ena" driver, but does not include the primary network interface. To find the primary network interface, nodeup reads the primary MAC address from the instance metadata and compares it with the sysfs data. The file uses the udev property "INTERFACE" for this, because a "Name=" entry also agrees with the alternative names of an interface.
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systemd-networkd uses the first file that agrees with an interface.
With the number 75, the per-interface files ("10-netplan-*" on Debian,
"70-*" on AL2023) come before this file. Thus the primary network
interface keeps its own file, and this gives more protection against
an incorrect match. The number 75 also comes before the AL2023
catch-all file "80-ec2.network". Thus the secondary ENIs stay
unmanaged.
Tests on EC2 (Debian 12 and AL2023, c8g.medium) show this order: the
primary network interface keeps its per-interface file, also without
the "Property=" exclusion, and a hot-attached ENI stays unmanaged.
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[APPROVALNOTIFIER] This PR is APPROVED This pull-request has been approved by: rifelpet The full list of commands accepted by this bot can be found here. The pull request process is described here DetailsNeeds approval from an approver in each of these files:
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Wow - thanks for fixing. Is there similar code in EKS or AWS-VPC-CNI - it feels like it would be a problem there also? |
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…-upstream-release-1.36 Automated cherry pick of #18642: aws: do not set the primary network interface to "Unmanaged=yes"
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The file "10-eni-secondary.network" causes systemd-networkd to ignore the secondary ENIs. Before this change, the file found the secondary ENIs by their interface names. The names were correct only if the primary network interface had the name "ens5". But the interface names are different for each instance family and each systemd naming scheme.
On Graviton4 instances, the primary network interface has the name "ens34". The file also found this interface. Thus systemd-networkd ignored the primary network interface, and systemd-resolved had no DNS servers for it.
On 8th-generation Intel instances, the interfaces have the names "enp39s0" and "enp40s0". The file did not find these interfaces. Thus the secondary ENIs had no protection.
With this change, the file finds all the interfaces that use the "ena" driver, but does not include the primary network interface. To find the primary network interface, nodeup reads the primary MAC address from the instance metadata and compares it with the sysfs data. The file uses the udev property "INTERFACE" for this, because a "Name=" entry also agrees with the alternative names of an interface.
/cc @rifelpet @ameukam