Don't install rules for the primary interface #98
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There's an expectation that containers on the docker0 bridge can communicate with the host on its primary interface's address. The practical way to accomplish that, without knowing additional information about the additional interfaces and/or prefixes involved, is to avoid creating a rule matching traffic from the primary interface's addresses and instead let the main table handle that traffic. Routing traffic from the primary interface via the main table was in place prior to version 2.4.0, which regressed. The tradeoff in fixing this is that traffic that specifically binds to one of device-number-0's addresses will be routed via the "wrong" table when trying to reach addresses reachable via a secondary ENI. The expected behavior in a VPC is that it it's routed via device-number-0, but according to entries in the main table it will be routed via the secondary ENI as the most direct path to the destination. This is consistent with Amazon Linux 2's routing behavior, and for that reason is considered desirable here as well. Fixes: 0a57c62 ("Route configuration simplification") Fixes: amazonlinux#97
vigh-m
approved these changes
Oct 19, 2023
nikolamz
approved these changes
Oct 19, 2023
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Issue #, if available: #97
Description of changes:
There's an expectation that containers on the docker0 bridge can communicate with the host on its primary interface's address. The practical way to accomplish that, without knowing additional information about the additional interfaces and/or prefixes involved, is to avoid creating a rule matching traffic from the primary interface's addresses and instead let the main table handle that traffic.
Routing traffic from the primary interface via the main table was in place prior to version 2.4.0, which regressed.
The tradeoff in fixing this is that traffic that specifically binds to one of device-number-0's addresses will be routed via the "wrong" table when trying to reach addresses reachable via a secondary ENI. The expected behavior in a VPC is that it it's routed via device-number-0, but according to entries in the main table it will be routed via the secondary ENI as the most direct path to the destination. This is consistent with Amazon Linux 2's routing behavior, and for that reason is considered desirable here as well.
Fixes: 0a57c62 ("Route configuration simplification")
Fixes: #97
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