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Type: Bug
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Resolution: Done
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Priority: Major - P3
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Affects Version/s: 2.4.10, 2.6.1
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Component/s: Replication
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None
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Fully Compatible
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ALL
'isself' should match the ports only if the hosts are being string matched. In cases where an instance is being addressed through a proxy port, port matching is an incorrect check - it invalidates a genuine match.
e.g. a mongod instance listening on port 27017 may be get redirected traffic from another port through IPtables routing. Such instances would fail to get added to a replica set for no good reason. Port proxies maybe required in multi-tenant cloud based systems where bind-able IPs/ports are NAT'ed.
Take this example replica set config to setup a one node cluster. The server itself can be addressed using a DNS name and an externally proxied port, but we cannot form a cluster if the same is used for the rs config.
config = { "id" : "test", "members" : [ { "_id" : 0, "host" : "public_dns_to_ec2_node:38132" } ] }
Internally, the mongod was bound to 127.0.0.1:27017 and we have IPtables proxy rule to route all tcp traffic from 38132 to 127.0.0.1:27017, e.g.
-A OUTPUT -d 10.203.77.175/32 -m tcp -p tcp --dport 38132 -j DNAT --to-destination 127.0.0.1:27017 -A PREROUTING -d 10.203.77.175/32 -m tcp -p tcp --dport 38132 -j DNAT --to-destination 127.0.0.1:27017
where 'public_dns_to_ec2_node' routes to 10.203.77.175 through public IP DNS registration.
With the above example it is clear that a fix is needed to not unnecessarily match the ports as integers. Or we cannot even create a one node cluster, leave aside a usable 3-node replica set.
- related to
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SERVER-14078 Verify >1 local interface works with isself
- Closed
- links to