Kubernetes Cassandra

Deploy Apache Cassandra in Kubernetes

Install

We utilize a "headless" service for Cassandra. This way we can provide a way for applications to access it via KubeDNS and not expose it to the outside. To access it from your developer workstation you can use kubectl exec commands against any of the cassandra pods.
If you do wish to connect an application to it you can use the KubeDNS value of cassandra.default.svc.cluster.local when configuring your application.

kubectl create -f service.yaml
kubectl create -f volumes.yaml
kubectl create -f statefulset.yaml

Scaling

To increase or decrease the size of your StatefulSet you can use the scale command:

$ kubectl scale --replicas=3 statefulset/cassandra

Check Cluster

You can perform a nodetool status to check if the other cassandra nodes have joined and formed a Cassandra cluster.

$ kubectl exec -ti cassandra-0 -- nodetool status

Datacenter: DC1
===============
Status=Up/Down
|/ State=Normal/Leaving/Joining/Moving
--  Address     Load        Tokens       Owns (effective)   Host ID                                 Rack
UN  10.1.4.99   80.05 KiB   256          69.3%              528a11d5-74a4-4768-a1aa-70de5998449b    Rack1
UN  10.1.4.98   74.94 KiB   256          61.9%              510c2b45-79ba-4717-8b7b-c7bc782fe6e7    Rack1
UN  10.1.4.101  236.12 KiB  256          68.9%              677859ee-ca59-42e1-9d6d-2632dfd3c13a    Rack1

Check Cassandra

You can access the cassandra container using the following command:

$ kubectl exec -it cassandra-0 cqlsh

Connected to Cassandra at 127.0.0.1:9042.
[cqlsh 5.0.1 | Cassandra 3.11.6 | CQL spec 3.4.4 | Native protocol v4]
Use HELP for help.
cqlsh>

Check tables :

cqlsh> describe tables


Keyspace system_traces
----------------------
events  sessions

Keyspace system_schema
----------------------
tables     triggers    views    keyspaces  dropped_columns
functions  aggregates  indexes  types      columns

Keyspace system_auth
--------------------
resource_role_permissons_index  role_permissions  role_members  roles

Keyspace system
---------------
available_ranges          peers               batchlog        transferred_ranges
batches                   compaction_history  size_estimates  hints
prepared_statements       sstable_activity    built_views
"IndexInfo"               peer_events         range_xfers
views_builds_in_progress  paxos               local

Keyspace system_distributed
---------------------------
repair_history  view_build_status  parent_repair_history