问题
I use Hyperledger Fabric 1.2 to build a blockchain cluster, which contains 3 peers and 3 orderers. I can successfully deploy and invoke the chaincode via both CLI and Java SDK. Everything works fine. However, when I notice the service discovery function and try to use it, I met two problems. First, after I build the discover tool and try to use it to get some discovered information, I can't access the peer and get the message as follow
"failed connecting to discovery service: failed to create new connection: context deadline exceeded"
The config command is
discover --configFile conf.yaml --userKey ./crypto-config/peerOrganizations/org1.forchain.com/peers/peer0.org1.forchain.com/msp/keystore/7458b29b1fb6a89768585430dbf0e522a40ff4aefe600fc1e4fafe62c3c972e4_sk --userCert ./crypto-config/peerOrganizations/org1.forchain.com/peers/peer0.org1.forchain.com/msp/signcerts/peer0.org1.forchain.com-cert.pem --MSP Org1MSP saveConfig
The query command is
discover --configFile conf.yaml peers --channel lajiao --server localhost:6051
I guess it may be caused by the TLS config so I canceled the TLS and tried again. This time I successfully access the peer and get some messages, but I met another problem. When I use 'discover peers xxx ' command, I always get null result, in fact there are two peers in that channel. When I use 'discover endorsers xxx' command, I always get the following error message
'failed constructing descriptor for chaincodes:'
In the meantime, the peer log outputs the following message:
'Principal set computation failed: chaincode isn't installed on sufficient organizations required by the endorsement policy 2018-08-01 10:21:50.860 UTC [discovery] chaincodeQuery -> ERRO 1441 Failed constructing descriptor for chaincode chaincodes: ,: chaincode isn't installed on sufficient organizations required by the endorsement policy'
I can assure that the chaincode is successfully installed in all peers. And I didn't use the endorsement policy when I instantiated the chaincode. I think it is not the policy problem because I still can invoke the chaincode and propose a transaction. I also tried to use the Java SDK and found that I can get the orderer nodes info but I can't get the other peer nodes or chaincode info. The log always output: "Discover of chaincode names was empty.". But the chaincode is definitely instantiated and can be invoke via SDK. I refered to the test code in "org.hyperledger.fabric.sdkintegration.ServiceDiscoveryIT" and some key Java code is as follow:
channel.addPeer(peer, createPeerOptions().setPeerRoles(EnumSet.of(Peer.PeerRole.SERVICE_DISCOVERY,Peer.PeerRole.LEDGER_QUERY, Peer.PeerRole.EVENT_SOURCE,Peer.PeerRole.CHAINCODE_QUERY)));
channel.initialize();
System.out.println("================ orderer ===============");
for (Orderer orderer : channel.getOrderers()) {
System.out.println(orderer.getName());
}
System.out.println("================ peer ===============");
for (Peer p: channel.getPeers()) {
System.out.println(p.getName());
}
System.out.println("================ chaincode ===============");
for (String s: channel.getDiscoveredChaincodeNames()) {
System.out.println(s);
}
So, how can I use the 'discover' command under TLS configuration and how can I get the discovered information?
回答1:
For the config command - you need to pass a TLS root CA, via --peerTLSCA. Please look at the examples in the documentation and act accordingly.
Now - for the second problem, I think that the peers might not know each other in the channel.
- Make sure you have anchor peers defined in the channel and that both peers have external endpoints configured.
- Feel free to bug me (yacovm) on chat.hyperledger.org if you're struggling for too long and can't solve the problem.
回答2:
I stumbled a similar error (regarding to service discovery) as below.
Go Fabric Client logs:
Failed to get endorsing peers: error getting channel response for channel [myc]:
Discovery status Code: (11) UNKNOWN. Description: error received from Discovery Server:
failed constructing descriptor for chaincodes:<name:"mycc">
Peer logs:
Failed constructing descriptor for chaincode chaincodes:<name:"mycc" > ,:
cannot satisfy any principal combination
It's fixed when I provide CORE_PEER_GOSSIP_EXTERNALENDPOINT environment attribute with a correct value on peer's configuration (in docker yaml file in my case).
As I understood since this attribute is missing, discovery services running on peers failed to communicate with each other to have a conclusion of what current network looks like.
回答3:
You must add an anchor peer from each organization in the channel, this solved the problem for me. Anchor peers are required for the service discovery since the service discovery uses gossip protocol- thanks @yacovm
来源：https://stackoverflow.com/questions/51631123/hyperledger-fabric-1-2-service-discovery-error