daemon: Remove defunct --single-cluster-route flag
#18426
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The `single-cluster-route` flag was intended to instruct Cilium to use a single route covering the entire cluster CIDR to point to the `cilium_host` interface in tunnel mode, instead of per-host or per-endpoint routes. However, the underlying concept of a cluster prefix used for routing was removed in PR cilium#10194. It seems the `single-cluster-route` flag was likely even broken prior to that and accidentally used the per-node mask instead of the per-cluster mask for the route. In summary, this flag has not been functional for almost two years. As no one seems to have noticed, it should be safe to remove this defunct flag without a deprecation period. Signed-off-by: Sebastian Wicki <sebastian@isovalent.com>
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--single-cluster-route flag--single-cluster-route flag
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Apparently, the implementation always used the node-local allocation CIDR. So it is not technically defunct and works as originally intended, even though that behavior is not what I expect given its description which clearly talks about a cluster CIDR. Closing this for now, as I still don't fully understand it's intended usage. Might remove it later. |
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Nov 16, 2023
This commit removes the ``single-cluster-route` flag. Contrary to it's description, it never [1] installed a cluster-wide route for `cilium_host`. Instead, it installed a route for the local alloc CIDR (aka local PodCIDR), virtually identical to the (enabled by default) `enable-local-node-route`. The only difference being that `single-cluster-route` sets the MTU. This means that the flag (which has not been referenced anywhere in the last four years) likely never worked as described. Marco Iorio recently tested the flag and found that the flag (when enabled) breaks node-to-pod and nodeport traffic. In addition, since the route conflicts with the local node route, we also found that the "single cluster route" was in fact overwritten by the "local node route". The only other effect the flag has is that it disables per-node routes, but those are needed for node-to-pod traffic. Removal has already been discussed two years ago [1]. Given that the flag has remained broken ever since and there have not been any bug reports at all, it is assumed that no one is actually using it. It is also not documented anywhere outside of the cmdref. Therefore, it is removed without prior deprecation. [1] cilium#18426 Signed-off-by: Sebastian Wicki <sebastian@isovalent.com>
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Nov 16, 2023
This commit removes the `single-cluster-route` flag. Contrary to it's description, it never [1] installed a cluster-wide route for `cilium_host`. Instead, it installed a route for the local alloc CIDR (aka local PodCIDR), virtually identical to the (enabled by default) `enable-local-node-route`. The only difference being that `single-cluster-route` sets the MTU. This means that the flag (which has not been referenced anywhere in the last four years) likely never worked as described. Marco Iorio recently tested the flag and found that the flag (when enabled) breaks node-to-pod and nodeport traffic. In addition, since the route conflicts with the local node route, we also found that the "single cluster route" was in fact overwritten by the "local node route". The only other effect the flag has is that it disables per-node routes, but those are needed for node-to-pod traffic. Removal has already been discussed two years ago [1]. Given that the flag has remained broken ever since and there have not been any bug reports at all, it is assumed that no one is actually using it. It is also not documented anywhere outside of the cmdref. Therefore, it is removed without prior deprecation. [1] cilium#18426 Signed-off-by: Sebastian Wicki <sebastian@isovalent.com>
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Nov 20, 2023
This commit removes the `single-cluster-route` flag. Contrary to it's description, it never [1] installed a cluster-wide route for `cilium_host`. Instead, it installed a route for the local alloc CIDR (aka local PodCIDR), virtually identical to the (enabled by default) `enable-local-node-route`. The only difference being that `single-cluster-route` sets the MTU. This means that the flag (which has not been referenced anywhere in the last four years) likely never worked as described. Marco Iorio recently tested the flag and found that the flag (when enabled) breaks node-to-pod and nodeport traffic. In addition, since the route conflicts with the local node route, we also found that the "single cluster route" was in fact overwritten by the "local node route". The only other effect the flag has is that it disables per-node routes, but those are needed for node-to-pod traffic. Removal has already been discussed two years ago [1]. Given that the flag has remained broken ever since and there have not been any bug reports at all, it is assumed that no one is actually using it. It is also not documented anywhere outside of the cmdref. Therefore, it is removed without prior deprecation. [1] #18426 Signed-off-by: Sebastian Wicki <sebastian@isovalent.com>
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This commit removes the `single-cluster-route` flag. Contrary to it's description, it never [1] installed a cluster-wide route for `cilium_host`. Instead, it installed a route for the local alloc CIDR (aka local PodCIDR), virtually identical to the (enabled by default) `enable-local-node-route`. The only difference being that `single-cluster-route` sets the MTU. This means that the flag (which has not been referenced anywhere in the last four years) likely never worked as described. Marco Iorio recently tested the flag and found that the flag (when enabled) breaks node-to-pod and nodeport traffic. In addition, since the route conflicts with the local node route, we also found that the "single cluster route" was in fact overwritten by the "local node route". The only other effect the flag has is that it disables per-node routes, but those are needed for node-to-pod traffic. Removal has already been discussed two years ago [1]. Given that the flag has remained broken ever since and there have not been any bug reports at all, it is assumed that no one is actually using it. It is also not documented anywhere outside of the cmdref. Therefore, it is removed without prior deprecation. [1] cilium#18426 Signed-off-by: Sebastian Wicki <sebastian@isovalent.com>
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The
single-cluster-routeflag was intended to instruct Cilium to use asingle route covering the entire cluster CIDR to point to the
cilium_hostinterface in tunnel mode, instead of per-host orper-endpoint routes.
However, the underlying concept of a cluster prefix used for routing was
removed in PR #10194. It seems the
single-cluster-routeflag was likely even broken prior to that and accidentally used the
per-node mask instead of the per-cluster mask for the route. In summary,
this flag has not been functional for almost two years. As no one seems
to have noticed, it should be safe to remove this defunct flag without a
deprecation period.