etcd租约机制

新建租约

新建一个过期时间为120s的租约

# etcdctl lease grant 120
lease 018f6d7bb11aba0d granted with TTL(120s)

查看新建的租约信息

# etcdctl lease list
found 1 leases
018f6d7bb11aba0d

  # etcdctl lease timetolive 018f6d7bb11aba0d --keys
  lease 018f6d7bb11aba0d granted with TTL(120s), remaining(99s), attached keys([])

新建key，并为该key指定租约

# etcdctl put name alice --lease="018f6d7bb11aba0d"
OK
# etcdctl put name1 tina --lease="018f6d7bb11aba0d"
OK

# etcdctl lease timetolive 018f6d7bb11aba0d --keys

lease 018f6d7bb11aba0d granted with TTL(120s), remaining(60s), attached keys([name name1])

  # etcdctl get --prefix ""
  name
  alice
  name1
  tina

等到租约过期后，再次查看租约已经过期，对应的key也已经被自动删除

# etcdctl lease timetolive 018f6d7bb11aba0d --keys
lease 018f6d7bb11aba0d already expired

 续约

新建租约并赋予key值

# etcdctl lease grant 30
lease 018f6d7bd032c117 granted with TTL(30s)
# etcdctl put name alice --lease=018f6d7bd032c117
OK

 在租约即将过期时进行续约，命令不会自动结束，会一直显示该窗口

# etcdctl lease keep-alive 018f6d7bd032c117
lease 018f6d7bd032c117 keepalived with TTL(30)
lease 018f6d7bd032c117 keepalived with TTL(30)
lease 018f6d7bd032c117 keepalived with TTL(30)
......

 重新打开一个窗口，查看该租约续约信息，可以看到该租约会自动续约，相应key值也不会被删除

# etcdctl lease timetolive 018f6d7bd032c117 --keys
lease 018f6d7bd032c117 granted with TTL(30s), remaining(23s), attached keys([name])
# etcdctl lease timetolive 018f6d7bd032c117 --keys
lease 018f6d7bd032c117 granted with TTL(30s), remaining(22s), attached keys([name])
# etcdctl lease timetolive 018f6d7bd032c117 --keys
lease 018f6d7bd032c117 granted with TTL(30s), remaining(21s), attached keys([name])
# etcdctl lease timetolive 018f6d7bd032c117 --keys
lease 018f6d7bd032c117 granted with TTL(30s), remaining(20s), attached keys([name])
# etcdctl lease timetolive 018f6d7bd032c117 --keys
lease 018f6d7bd032c117 granted with TTL(30s), remaining(29s), attached keys([name])
# etcdctl lease timetolive 018f6d7bd032c117 --keys
lease 018f6d7bd032c117 granted with TTL(30s), remaining(28s), attached keys([name])
# etcdctl lease timetolive 018f6d7bd032c117 --keys
lease 018f6d7bd032c117 granted with TTL(30s), remaining(27s), attached keys([name])
# etcdctl lease timetolive 018f6d7bd032c117 --keys
lease 018f6d7bd032c117 granted with TTL(30s), remaining(27s), attached keys([name])
# etcdctl lease timetolive 018f6d7bd032c117 --keys
lease 018f6d7bd032c117 granted with TTL(30s), remaining(26s), attached keys([name])
# etcdctl lease timetolive 018f6d7bd032c117 --keys
lease 018f6d7bd032c117 granted with TTL(30s), remaining(25s), attached keys([name])
# etcdctl lease timetolive 018f6d7bd032c117 --keys
lease 018f6d7bd032c117 granted with TTL(30s), remaining(25s), attached keys([name])
# etcdctl lease timetolive 018f6d7bd032c117 --keys
lease 018f6d7bd032c117 granted with TTL(30s), remaining(24s), attached keys([name])
# etcdctl lease timetolive 018f6d7bd032c117 --keys
lease 018f6d7bd032c117 granted with TTL(30s), remaining(23s), attached keys([name])
# etcdctl lease timetolive 018f6d7bd032c117 --keys
lease 018f6d7bd032c117 granted with TTL(30s), remaining(22s), attached keys([name])
# etcdctl lease timetolive 018f6d7bd032c117 --keys
lease 018f6d7bd032c117 granted with TTL(30s), remaining(22s), attached keys([name])
# etcdctl lease timetolive 018f6d7bd032c117 --keys
lease 018f6d7bd032c117 granted with TTL(30s), remaining(20s), attached keys([name])
# etcdctl lease timetolive 018f6d7bd032c117 --keys
lease 018f6d7bd032c117 granted with TTL(30s), remaining(29s), attached keys([name])

回收租约 

回收租约会自动删除与该租约关联的key

# etcdctl lease revoke 018f6d7bd032c117
lease 018f6d7bd032c117 revoked
# etcdctl lease timetolive 018f6d7bd032c117 --keys
lease 018f6d7bd032c117 already expired
# etcdctl get name