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Caution
You're viewing documentation for an unstable version of Scylla Operator. Switch to the latest stable version.
Using Alternator (DynamoDB)¶
Alternator is a DynamoDB compatible API provided by ScyllaDB. You can enable it on your ScyllaClusters by adding this section:
spec:
alternator: {}
While this is enough to turn it on, there are more options available. Please refer to our API documentation for details.
Note
Contrary to CQL clients, Alternator clients don’t need to connect to every ScyllaDB node directly, nor discover the ScyllaDB node IP addresses. Alternator protocol is based on HTTP and you can also expose the service “manually” with other networking concepts like Ingresses.
Credentials¶
Scylla Operator enables Alternator authorization by default. Here is a quick example of how to get the token for accessing Alternator API. To find out more, please refer to ScyllaDB Alternator documentation.
Caution
The salted_hash is only present if password authentication for CQL is set up.
Always make sure your clusters are configured to use Authentication and Authorization.
Tip
You can find a quick example that enables Authentication and Authorization here.
kubectl exec -it service/<sc-name>-client -c scylla -- cqlsh --user <cql_user> \
-e "SELECT salted_hash FROM system_auth.roles WHERE role = '<cql_user>'"
AWS CLI¶
This paragraph shows how to use aws dynamodb cli to remotely connect to ScyllaDB Alternator API.
Note
This example uses Service ClusterIP to connect to the ScyllaDB cluster. If you have configured networking options differently, or are using additional networking concepts like Ingresses, this address will need to be adjusted.
Caution
At the time of writing this document kubectl exec -i echoes passwords into the terminal.
It can be avoided by manually running kubectl exec -it and copying the output into a file / variable.
Because using kubectl exec with -t option merges standard and error outputs, we can’t use it in the scripts bellow.
See https://github.com/kubernetes/kubernetes/issues/123913 for more details.
SCYLLACLUSTER_NAME=scylladb
CQL_USER=cassandra
SCYLLADB_EP="$( kubectl get "service/${SCYLLACLUSTER_NAME}-client" -o='jsonpath={.spec.clusterIP}' )"
AWS_ENDPOINT_URL_DYNAMODB="https://${SCYLLADB_EP}:8043"
export AWS_ENDPOINT_URL_DYNAMODB
AWS_ACCESS_KEY_ID="${CQL_USER}"
export AWS_ACCESS_KEY_ID
AWS_SECRET_ACCESS_KEY="$( kubectl exec -i "service/${SCYLLACLUSTER_NAME}-client" -c scylla -- cqlsh --user ${CQL_USER} --no-color \
-e "SELECT salted_hash from system_auth.roles WHERE role = '${AWS_ACCESS_KEY_ID}';" \
| sed -e 's/\r//g' | sed -e '4q;d' | sed -E -e 's/^\s+//' )"
export AWS_SECRET_ACCESS_KEY
AWS_CA_BUNDLE="$( mktemp )"
export AWS_CA_BUNDLE
kubectl get "configmap/${SCYLLACLUSTER_NAME}-alternator-local-serving-ca" --template='{{ index .data "ca-bundle.crt" }}' > "${AWS_CA_BUNDLE}"
Now we can use aws dynamodb cli without modifications.
aws dynamodb create-table --table-name MusicCollection --attribute-definitions AttributeName=Artist,AttributeType=S AttributeName=SongTitle,AttributeType=S --key-schema AttributeName=Artist,KeyType=HASH AttributeName=SongTitle,KeyType=RANGE --provisioned-throughput ReadCapacityUnits=5,WriteCapacityUnits=5
TABLEDESCRIPTION 2024-03-01T16:35:41+01:00 5c8aae70-d7e1-11ee-a99e-6f31aaf1d6d3 MusicCollection ACTIVE
ATTRIBUTEDEFINITIONS Artist S
ATTRIBUTEDEFINITIONS SongTitle S
KEYSCHEMA Artist HASH
KEYSCHEMA SongTitle RANGE
PROVISIONEDTHROUGHPUT 5 5
aws dynamodb list-tables
TABLENAMES MusicCollection