Ignore previous serf user events to avoid wrong fdb programming#1639
Ignore previous serf user events to avoid wrong fdb programming#1639aboch merged 1 commit intomoby:masterfrom
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drivers/overlay/ov_serf.go
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| return | ||
| } | ||
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| logrus.Debugf("Sending peer query resp %v", fmt.Sprintf("%s %s %s", peerMac.String(), net.IP(peerIPMask).String(), vtep.String())) |
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why %v is you are actually formatting a string as parameter, should be %s
peerIPMask is already of type net.IP no need to cast
net.HardwareAddr, net.IPMask and net.IP implement String() string, you do not need to call it.
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I am taking the same fmt.Sprintf we have in the next line and throwing it in a debug. Are you suggesting that its better to print the fields individually in the debug ?
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IMO, unnecessary casting make the code bloated.
It is a minor comment, you don't need to change it.
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Ok, I will change it to avoid the cast and explicit string conversion.
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@aboch Made the change.
peerIPMask is ok type net.IPMask and the default Stringer for net.IPMask is different from net.IP. That is why it was casted explicitly.
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This change can be reverted (if we can avoid querying the cluster its better) if the serf ordering can be fixed. |
drivers/overlay/ov_serf.go
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| func (d *driver) processEvent(u serf.UserEvent) { | ||
| logrus.Debugf("Received user event name:%s, payload:%s\n", u.Name, | ||
| string(u.Payload)) | ||
| logrus.Debugf("Received user event name:%s, payload:%s LTime:%v \n", u.Name, |
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%v -> %d since you know it is a uint64
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@aboch %v does exactly that. Its just easier to use the default specifier.
From https://golang.org/pkg/fmt/
The default format for %v is:
bool: %t
int, int8 etc.: %d
uint, uint8 etc.: %d, %x if printed with %#v
float32, complex64, etc: %g
string: %s
chan: %p
pointer: %p
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Yeah we know that. It just looks weird in the same Debufg call you mix the dedicated verb %s with the generic one %v when you exactly know the type of each argument.
As I said it is minor comment. You don't have to change it.
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LGTM besides few minor comments |
Signed-off-by: Santhosh Manohar <santhosh@docker.com>
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LGTM again |
3 participants
When deploying classic swarm with overlay network and using
on-node-failurereschedule policy randomly some containers might have connectivity issues with other containers in the same network.To illustrate: One container C1 with three worker nodes W1, W2 and W3.
Container interface's mac is built from the IP address.
Let say C1 has 10.0.0.2 and mac 02:42:0a:00:00:02. If its initially scheduled on W1 the reachability info will be distributed to other nodes will be
<join 10.0.0.2, 02:42:0a:00:00:02, VTEP IP of W1>If W1 goes through a failure and the container gets rescheduled to W2 the results events will be
<leave 10.0.0.2, 02:42:0a:00:00:02, VTEP IP of W1><join 10.0.0.2, 02:42:0a:00:00:02, VTEP IP of W2>At this point if W3's daemon is restarted serf replays all the previous events. But they can be delivered out of order to the client. So libnetwork could end up getting the following..
<join 10.0.0.2, 02:42:0a:00:00:02, VTEP IP of W2><leave 10.0.0.2, 02:42:0a:00:00:02, VTEP IP of W1><join 10.0.0.2, 02:42:0a:00:00:02, VTEP IP of W1>W3 ends up with incorrect forwarding info.
The change is to avoid getting the older events from serf when joining the gossip cluster. Hence for the containers that are already running in the network the miss notification and query mechanism will be used to program the neighbor entry/FDB.
Also added some debugs to help in debugging.
Signed-off-by: Santhosh Manohar santhosh@docker.com