etcd stays up when it cannot possibly proceed

[bcwaldon]

I deployed etcd from the raft branch at commit 0b2fdd6. Consider the following logs:

Aug 28 14:30:54 ip-10-138-52-213.ec2.internal etcd[6697]: 2014/08/28 14:30:54 name=a2fa842729214a428a2a
96c7e1ba37b0 server.new raftPubAddr=http://10.138.52.213:7001
Aug 28 14:30:54 ip-10-138-52-213.ec2.internal etcd[6697]: 2014/08/28 14:30:54 etcd server starts listen
ing on :4001
Aug 28 14:30:54 ip-10-138-52-213.ec2.internal etcd[6697]: 2014/08/28 14:30:54 etcd server starts servin
g HTTP
Aug 28 14:30:54 ip-10-138-52-213.ec2.internal etcd[6697]: 2014/08/28 14:30:54 discoverer name=a2fa84272
9214a428a2a96c7e1ba37b0 target="["https://discovery.etcd.io"]" prefix=/9cebb7746f4a049af2ef066d87dbef3d
Aug 28 14:30:54 ip-10-138-52-213.ec2.internal etcd[6697]: 2014/08/28 14:30:54 raft server starts listen
ing on :7001
Aug 28 14:30:54 ip-10-138-52-213.ec2.internal etcd[6697]: 2014/08/28 14:30:54 raft server starts servin
g HTTP
Aug 28 14:30:55 ip-10-138-52-213.ec2.internal etcd[6697]: 2014/08/28 14:30:55 name=a2fa842729214a428a2a
96c7e1ba37b0 server.run source=-discovery seeds=["http://10.141.164.134:7001" "http://10.236.135.216:70
01"]
Aug 28 14:30:55 ip-10-138-52-213.ec2.internal etcd[6697]: 2014/08/28 14:30:55 id=0 participant.new.mkdi
r err=mkdir /var/lib/etcd/snap: permission denied
Aug 28 14:30:55 ip-10-138-52-213.ec2.internal etcd[6697]: 2014/08/28 14:30:55 name=a2fa842729214a428a2a96c7e1ba37b0 server.run newParicipanteErr="mkdir /var/lib/etcd/snap: permission denied"

etcd started, bound on both server ports, then failed to continue operation due to the inability to create /var/lib/etcd/snap.

Given that etcd cannot possibly proceed, I suggest two things:

1. do all setup before binding server ports as to not mislead clients
2. exit when any part of setup (like creating a directory) fails