通路Cassandra
Cassandra叢集中的機器沒有主從或者線性關系，分布式的叢集可以通過通路叢集中任一機器的cassandra來連接配接cassandra叢集。
Cassandra 叢集可以有無數個節點
cqlsh連接配接cassandra
[[email protected] ~]# cqlsh -u username -pdbname ip1
Connected to DBS Cluster at ip1:9042.
[cqlsh 5·0·1 | Cassandra 3·10 | CQL spec 3·4·4 | Native protocol v4]
Use HELP for help.
cqlsh> select cluster_name, listen_address from system.local;
cluster_name | listen_address
DBS Cluster | ip1
(1 rows)
cqlsh>
Python連接配接cassandra
在Cassandra 叢集部署(二)——Ntpd和Python、Java安裝文章中我們介紹了python pip安裝指令pip install cassandra-drive安裝Python通路Cassandra的驅動包，現在我們在指令行運作python直接通路測試
[[email protected] ~]# python
Python 2.7.13 (default, Jun 2 2017, 10:12:53)
[GCC 4.4.7 20120313 (Red Hat 4·4·7-18)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from cassandra.cluster import Cluster
>>> from cassandra.auth import PlainTextAuthProvider
>>> cluster = Cluster(['ip1'],auth_provider=PlainTextAuthProvider(username='username', password='password'))
>>> session = cluster.connect('system')
>>> rows = session.execute('select cluster_name, listen_address from local')
>>> for row in rows:
... print(row)
Row(cluster_name=u'DBS Cluster', listen_address='ip1')