Setting security keyspaces replication factors
Prerequisite, increase replication factors (RF) for security keyspaces which manage authentication and authorization to prevent lockouts and ensure consistency across the cluster.
system_auth
dse_security
system_auth
keyspace RF. If
the keyspace is not available, the cassandra account log in fails. The cassandra
account uses a consistency level of QUORUM for all requests. Security keyspaces and tables
Read access to these system tables is implicitly given to every authenticated user because the tables are used by most DSE tools:
system_auth keyspace
Contains authorization and internal authentication data.
Table | Columns | Description |
---|---|---|
resource_role_permissons_index | resource (PK), role | Stores the role and a resource that the role has a set permission. |
role_permissions | role (PK), resource, permissions | Stores the role, resource (for example keyspace_name/table_name), and the permission that the role has to access the resource. |
role_members | role (PK), member | Stores the roles and role members. |
roles | role (PK), can_login, is_superuser, member_of, salted_hash | Stores the role name, whether the role can be used for login, whether the role is a superuser, what other roles the role may be a member of, and a bcrypt salted hash password for the role. |
dse_security keyspace
Contains DSE Spark, Kerberos digest data, and role options.
Table | Columns | Description |
---|---|---|
role_options | role, options | Role options. |
digest_tokens | id, password | Kerberos digest tokens when enabled. |
spark_security | dc, shared_secret | Share secret for Spark. |
Default replication factors
The default replication factor for the
system_auth
and dse_security
keyspaces is 1.
All analytics keyspaces are initially created with the
SimpleStrategy
replication strategy and a replication factor
(RF) of 1. Each of these must be updated in production environments to avoid data
loss. DataStax recommends
changing the replication factor before enabling authentication. DSE uses a
consistency level of LOCAL_ONE
for all security keyspaces queries,
except when using the cassandra role. For the cassandra role, DSE uses the
consistency level QUORUM
. Only use the cassandra role to login and
create your own full access account and then drop the cassandra role.
Recommended replication factors
Determine the appropriate RF based on your failure tolerance and the size of your deployment.
system_auth
: Required for each log in and for every action that affects a database object; once a user logs in their credentials, roles, and permissions are cached for a period set in the cassandra.yaml, see Security properties. Contains LDAP, native authentication, and authorization related data. When the keyspace is unavailable logins and actions may fail. When located on a node in another datacenter, may cause delays that also can lead to failures. The keyspace tables are relatively small.DataStax recommends using a replication factor of
3
,4
, or5
per datacenter.Note: DSE caches security data, to adjust cache interval see Security properties.dse_security
: Contains DSE Analytic (Spark), DSE Client digest tokens, and other Kerberos related data. Required for related DSE services, less critical for pure database activities.DataStax recommends using a replication factor of
1
per datacenter if none of these services are present.Note: See the corresponding set up instructions for recommendeddse_security
if these services are present.
Procedure
-
Change the
system_auth
keyspace RF:ALTER KEYSPACE system_auth WITH REPLICATION= {'class' : 'NetworkTopologyStrategy', 'data_center_name' : N, 'data_center_name' : N};
Note: Every time you add or remove a datacenter, you must manually reconfigure thesystem_auth
keyspace. -
Change the dse_security keyspace RF:
ALTER KEYSPACE dse_security WITH REPLICATION= {'class' : 'NetworkTopologyStrategy', 'data_center_name' : N, 'data_center_name' : N};
Important: Every time you add or remove a datacenter, you must manually reconfigure thedse_security
keyspace. If DataStax Enterprise or Spark security options are enabled on the cluster, you must also increase the replication factor for thedse_leases
keyspace across all logical datacenters. -
Run the nodetool repair on the security
keyspaces.
nodetool repair --full system_auth nodetool repair --full dse_security
Note: After changing the replication strategy, you must runnodetool repair
with the --full option.