aws cdk for Elasticache Redis Cluster - aws-cdk

Question

I have gone through the https://docs.aws.amazon.com/cdk/api/latest/python/aws_cdk.aws_elasticache.html.
How to create an Elasticache Redis template using AWS-CDK. It would be more helpful if you share the sample code.

Answer 1

sorry for late response but can be usefull for others.
CDK doesn't have an High Level Construct to create a Redis Cluster, but you can create it by using the low level construct api.
For Redis Cluster types you can take a look at this: https://aws.amazon.com/it/blogs/database/work-with-cluster-mode-on-amazon-elasticache-for-redis/
I've created a single Redis (no replication) Cluster using typescript like this:
const subnetGroup = new CfnSubnetGroup(
this,
"RedisClusterPrivateSubnetGroup",
{
cacheSubnetGroupName: "privata",
subnetIds: privateSubnets.subnetIds,
description: "subnet di sviluppo privata"
}
);
const redis = new CfnCacheCluster(this, `RedisCluster`, {
engine: "redis",
cacheNodeType: "cache.t2.small",
numCacheNodes: 1,
clusterName: "redis-sviluppo",
vpcSecurityGroupIds: [vpc.defaultSecurityGroup.securityGroupId],
cacheSubnetGroupName: subnetGroup.cacheSubnetGroupName
});
redis.addDependsOn(subnetGroup);
If you need a Redis (cluster enabled) Cluster you can you replication group
const redisSubnetGroup = new CfnSubnetGroup(
this,
"RedisClusterPrivateSubnetGroup",
{
cacheSubnetGroupName: "privata",
subnetIds: privateSubnets.subnetIds,
description: "subnet di produzione privata"
}
);
const redisReplication = new CfnReplicationGroup(
this,
`RedisReplicaGroup`,
{
engine: "redis",
cacheNodeType: "cache.m5.xlarge",
replicasPerNodeGroup: 1,
numNodeGroups: 3,
automaticFailoverEnabled: true,
autoMinorVersionUpgrade: true,
replicationGroupDescription: "cluster redis di produzione",
cacheSubnetGroupName: redisSubnetGroup.cacheSubnetGroupName
}
);
redisReplication.addDependsOn(redisSubnetGroup);
Hope this help.

Answer 2

I just struggled for hours creating a Redis cluster mode enabled with just one shard but two nodes. If you create a CfnReplicationGroup with num_cache_clusters=2, it will create a primary & replica node.
The trick is to create a CfnReplicationGroup with num_cache_clusters=2 and set the cache_parameter_group_name="default.redis6.x.cluster.on"
Then it will create a redis cache with cluster mode enable, one shard but two nodes