ETCD监控

Watch key changes

Applications can watch on a key or a range of keys to monitor for any updates.

Here is the command to watch on key foo:

$ etcdctl watch foo
# in another terminal: etcdctl put foo bar PUT foo bar

Here is the command to watch on key foo in hex format:

$ etcdctl watch foo --hex
# in another terminal: etcdctl put foo bar PUT \x66\x6f\x6f # Key \x62\x61\x72 # Value

Here is the command to watch on a range key from foo to foo9:

$ etcdctl watch foo foo9
# in another terminal: etcdctl put foo bar PUT foo bar # in another terminal: etcdctl put foo1 bar1 PUT foo1 bar1

Here is the command to watch on keys having prefix foo:

$ etcdctl watch --prefix foo
# in another terminal: etcdctl put foo bar PUT foo bar # in another terminal: etcdctl put fooz1 barz1 PUT fooz1 barz1

Here is the command to watch on multiple keys foo and zoo:

$ etcdctl watch -i
$ watch foo
$ watch zoo
# in another terminal: etcdctl put foo bar PUT foo bar # in another terminal: etcdctl put zoo val PUT zoo val

监控历史版本变化，为了解决监控期间故障，保证数据更新不会丢失

Suppose we finished the following sequence of operations:

$ etcdctl put foo bar         # revision = 2 OK $ etcdctl put foo1 bar1 # revision = 3 OK $ etcdctl put foo bar_new # revision = 4 OK $ etcdctl put foo1 bar1_new # revision = 5 OK

# watch for changes on key `foo` since revision 2 $ etcdctl watch --rev=2 foo PUT foo bar PUT foo bar_new

# watch for changes on key `foo` since revision 3 $ etcdctl watch --rev=3 foo PUT foo bar_new

$ etcdctl watch --prev-kv foo=====最近的修改前和修改后
# in another terminal: etcdctl put foo bar_latest PUT foo # key bar_new # last value of foo key before modification foo # key bar_latest # value of foo key after modification

版本压缩

$ etcdctl compact 5
compacted revision 5

# any revisions before the compacted one are not accessible $ etcdctl get --rev=4 foo Error: rpc error: code = 11 desc = etcdserver: mvcc: required revision has been compacted


授予租约

# grant a lease with 10 second TTL $ etcdctl lease grant 10 lease 32695410dcc0ca06 granted with TTL(10s) # attach key foo to lease 32695410dcc0ca06 $ etcdctl put --lease=32695410dcc0ca06 foo bar OK

Suppose we finished the following sequence of operations:

$ etcdctl lease grant 10
lease 32695410dcc0ca06 granted with TTL(10s)
$ etcdctl put --lease=32695410dcc0ca06 foo bar
OK

取消租约会删除所有附加的KEY

Here is the command to revoke the same lease:

$ etcdctl lease revoke 32695410dcc0ca06
lease 32695410dcc0ca06 revoked

$ etcdctl get foo
# empty response since foo is deleted due to lease revocation

查看租约信息

# grant a lease with 500 second TTL $ etcdctl lease grant 500 lease 694d5765fc71500b granted with TTL(500s) # attach key zoo1 to lease 694d5765fc71500b $ etcdctl put zoo1 val1 --lease=694d5765fc71500b OK # attach key zoo2 to lease 694d5765fc71500b $ etcdctl put zoo2 val2 --lease=694d5765fc71500b OK

Here is the command to get information about the lease:

$ etcdctl lease timetolive 694d5765fc71500b
lease 694d5765fc71500b granted with TTL(500s), remaining(258s)

Here is the command to get information about the lease along with the keys attached with the lease:

 

$ etcdctl lease timetolive --keys 694d5765fc71500b

lease 694d5765fc71500b granted with TTL(500s), remaining(132s), attached keys([zoo2 zoo1])