Concern only about flannel ip addresses #1401
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jcaamano
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rajatchopra
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Feb 18, 2021
pkg/ip/iface.go
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| // If there exist multiple addresses on link, it returns an error message to tell callers to remove additional address. | ||
| func EnsureV4AddressOnLink(ipn IP4Net, link netlink.Link) error { | ||
| addr := netlink.Addr{IPNet: ipn.ToIPNet()} | ||
| // EnsureV4AddressOnLink ensures that there is only one v4 Addr on `link` within the `net` address space and it equals `ipn`. |
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s/and it equals ipn/and it equals ipa/ ?
| if err := netlink.AddrDel(link, &existingAddrs[0]); err != nil { | ||
| return fmt.Errorf("failed to remove IP address %s from %s: %s", ipn.String(), link.Attrs().Name, err) | ||
| if ipn.Contains(FromIP(existingAddr.IP)) { | ||
| if err := netlink.AddrDel(link, &existingAddr); err != nil { |
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Can we log this as Info nevertheless? Useful since we are doing kind of a 'destructive' operation.
Currently flannel interface ip addresses are checked on startup when using vxlan and ipip backends. If multiple addresses are found, startup fails fatally. If only one address is found and is not the currently leased one, it will be assumed that it comes from a previous lease and be removed. This criteria seems arbitrary both in how it is done and in its timing. It may cause failures in situations where it might not be strictly necessary like for example if the node is running a dhcp client that is assigning link local addresses to all interfaces. It also might fail at flannel unexpected restarts which are completly unrelated to the external event that caused the unexpected modification in the flannel interface. This patch proposes to concern and check only ip address within the flannel network and takes the simple approach to ignore any other ip addresses assuming these would pose no problem on flannel operation. A discarded but more agressive alternative would be to remove all addresses that are not the currently leased one. Fixes flannel-io#1060 Signed-off-by: Jaime Caamaño Ruiz <jcaamano@suse.com>
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Addressed comments, thanks! |
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Description
Currently flannel interface ip addresses are checked on startup when
using vxlan and ipip backends. If multiple addresses are found, startup
fails fatally. If only one address is found and is not the currently
leased one, it will be assumed that it comes from a previous lease and
be removed.
This criteria seems arbitrary both in how it is done and in its timing.
It may cause failures in situations where it might not be strictly
necessary like for example if the node is running a dhcp client that is
assigning link local addresses to all interfaces. It also might fail at
flannel unexpected restarts which are completly unrelated to
the external event that caused the unexpected modification in the
flannel interface.
This patch proposes to concern and check only ip address within the
flannel network and takes the simple approach to ignore any other ip
addresses assuming these would pose no problem on flannel operation.
A discarded but more agressive alternative would be to remove all
addresses that are not the currently leased one.
Fixes #1060
Signed-off-by: Jaime Caamaño Ruiz jcaamano@suse.com