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Amazon ElastiCache

Manage cache-cluster records and parameter-group settings.

Plan: Pro75 of 75 operations implemented

The tested cluster returns a configuration port of 0 and generated cache hostnames; a working cache connection was not verified.

Example checked on Vera 1.2.2, 8 November 2026. Each coverage note names its own evidence and date.

Connect

Section titled “Connect”

Activate your license key and start the emulator with the Vera launcher, as in Activate Pro, then run this in a terminal of its own, from an empty scratch directory. It gives the official AWS CLI dummy credentials and a config file of its own, so no AWS account is needed and your own AWS profile isn't touched.

Terminal window
export VERA_ENDPOINT="http://localhost:5003"
export AWS_ACCESS_KEY_ID=test AWS_SECRET_ACCESS_KEY=test
export AWS_REGION=us-east-1 AWS_DEFAULT_REGION=us-east-1
export AWS_SHARED_CREDENTIALS_FILE=/dev/null
export AWS_EC2_METADATA_DISABLED=true
export AWS_PAGER="" AWS_CLI_AUTO_PROMPT=off
unset AWS_PROFILE AWS_DEFAULT_PROFILE
unset AWS_SESSION_TOKEN AWS_SECURITY_TOKEN
unset AWS_WEB_IDENTITY_TOKEN_FILE AWS_ROLE_ARN AWS_ROLE_SESSION_NAME
unset AWS_CONTAINER_CREDENTIALS_FULL_URI
unset AWS_CONTAINER_CREDENTIALS_RELATIVE_URI
cat > vera-aws-config <<'EOF'
[default]
region = us-east-1
output = json
cli_binary_format = base64
s3 =
    addressing_style = path
EOF
export AWS_CONFIG_FILE="$PWD/vera-aws-config"

When you've finished every example in this terminal, close it and delete vera-aws-config, not before.

The example uses the AWS CLI’s elasticache commands. The emulator serves the 2015-02-02 API over the AWS Query protocol, and the example was checked with the official AWS CLI 2.31.35.

Example

Section titled “Example”

Create a Redis parameter group, change its maxmemory-policy, then create a cache cluster that uses it.

Terminal window
aws --endpoint-url "$VERA_ENDPOINT" elasticache create-cache-parameter-group \
  --cache-parameter-group-name docs-redis --cache-parameter-group-family redis7 \
  --description 'Documentation metadata example'
aws --endpoint-url "$VERA_ENDPOINT" elasticache describe-cache-parameter-groups \
  --cache-parameter-group-name docs-redis
aws --endpoint-url "$VERA_ENDPOINT" elasticache modify-cache-parameter-group \
  --cache-parameter-group-name docs-redis \
  --parameter-name-values ParameterName=maxmemory-policy,ParameterValue=allkeys-lru
aws --endpoint-url "$VERA_ENDPOINT" elasticache describe-cache-parameters \
  --cache-parameter-group-name docs-redis --source user

The last command returns the changed parameter, with these fields:

Output (selected fields)
{
    "Parameters": [
        {
            "ParameterName": "maxmemory-policy",
            "ParameterValue": "allkeys-lru",
            "Source": "user",
            "IsModifiable": true
        }
    ]
}

allkeys-lru is a stored setting: it doesn’t show that a cache evicts keys.

Create a cluster with that parameter group and describe it:

Terminal window
aws --endpoint-url "$VERA_ENDPOINT" elasticache create-cache-cluster \
  --cache-cluster-id docs-cache --engine redis --cache-node-type cache.t3.micro \
  --num-cache-nodes 1 --cache-parameter-group-name docs-redis
aws --endpoint-url "$VERA_ENDPOINT" elasticache describe-cache-clusters \
  --cache-cluster-id docs-cache --show-cache-node-info

The create reports the cluster’s CacheClusterStatus as creating, and the description reports it available, with one cache node. Its ConfigurationEndpoint is {"Port": 0}, while CacheNodes[0].Endpoint has a generated *.cache.amazonaws.com address and port 6379. Don’t try to connect to that address: it’s a generated name, and no cache server behind it was verified.

To clean up, delete the cluster, then the parameter group:

Terminal window
aws --endpoint-url "$VERA_ENDPOINT" elasticache delete-cache-cluster --cache-cluster-id docs-cache
aws --endpoint-url "$VERA_ENDPOINT" elasticache delete-cache-parameter-group \
  --cache-parameter-group-name docs-redis

Supported features

Section titled “Supported features”
  • Parameter groups, created for a family such as redis7, described, changed, read and deleted. A changed parameter reads back with Source set to user.
  • Cache cluster records, created with an engine, node type, node count and parameter group, described and deleted. They move from creating to available at once.
  • Also served, not yet tested: replication groups and global replication groups, serverless caches, snapshots, users and user groups, subnet and security groups, reserved nodes, failover tests, migrations, service updates and tags.

Limitations

Section titled “Limitations”

The main limits are below. A few more apply to every service, and the API coverage notes cover smaller differences.

  • No cache connection was verified. The described cluster’s configuration endpoint has port 0, and its node’s endpoint is a generated *.cache.amazonaws.com address on port 6379. No Redis, Valkey or Memcached client was connected, so an available record doesn’t mean a cache server is running.
  • Parameters are stored, not applied. A changed parameter such as maxmemory-policy reads back, but nothing shows that a cache behaves differently because of it.
  • Only Redis was tested. No Valkey or Memcached clusters were created.
  • No provisioning delay. A new cluster is available as soon as it’s described.
  • Other features weren’t revalidated. Snapshots, replication, failover, scaling, encryption, users and user groups, subnet and security groups, multi-AZ and maintenance windows weren’t checked in Vera 1.2.0 preview or Vera 1.2.0-rc.3.

API coverage

Section titled “API coverage”

Every operation in AWS's published 2015-02-02 API (SDK model, botocore 1.43.105), and whether the emulator implements it. Availability combines the earlier implementation inventory with the dated observations below; checking a page's example does not verify every operation. Each note names its evidence first; an observation given without a build or date comes from earlier testing, on 3 November 2026. What the statuses mean

OperationStatusNotes
AddTagsToResourceImplemented
AuthorizeCacheSecurityGroupIngressImplemented
BatchApplyUpdateActionImplemented
BatchStopUpdateActionImplemented
CompleteMigrationImplemented
CopyServerlessCacheSnapshotImplemented
CopySnapshotImplemented
CreateCacheClusterImplementedLocal observation: Vera 1.2.0 preview, 5 November 2026 — created a Redis cluster record reported as creating. No cache server was verified.
CreateCacheParameterGroupImplemented
CreateCacheSecurityGroupImplemented
CreateCacheSubnetGroupImplemented
CreateGlobalReplicationGroupImplemented
CreateReplicationGroupImplemented
CreateServerlessCacheImplemented
CreateServerlessCacheSnapshotImplemented
CreateSnapshotImplemented
CreateUserImplemented
CreateUserGroupImplemented
DecreaseNodeGroupsInGlobalReplicationGroupImplemented
DecreaseReplicaCountImplemented
DeleteCacheClusterImplemented
DeleteCacheParameterGroupImplemented
DeleteCacheSecurityGroupImplemented
DeleteCacheSubnetGroupImplemented
DeleteGlobalReplicationGroupImplemented
DeleteReplicationGroupImplemented
DeleteServerlessCacheImplemented
DeleteServerlessCacheSnapshotImplemented
DeleteSnapshotImplemented
DeleteUserImplemented
DeleteUserGroupImplemented
DescribeCacheClustersImplementedReported a new cluster as available straight after creation, with a configuration endpoint on port 0. Local observation: Vera 1.2.0 preview, 5 November 2026 — described the cluster available with one cache node: ConfigurationEndpoint had port 0, and the node's endpoint was a generated *.cache.amazonaws.com address on port 6379. No cache connection was checked.
DescribeCacheEngineVersionsImplemented
DescribeCacheParameterGroupsImplemented
DescribeCacheParametersImplementedLocal observation: Vera 1.2.0 preview, 5 November 2026 — returned the changed parameter with Source user and IsModifiable true.
DescribeCacheSecurityGroupsImplemented
DescribeCacheSubnetGroupsImplemented
DescribeEngineDefaultParametersImplemented
DescribeEventsImplemented
DescribeGlobalReplicationGroupsImplemented
DescribeReplicationGroupsImplemented
DescribeReservedCacheNodesImplemented
DescribeReservedCacheNodesOfferingsImplemented
DescribeServerlessCacheSnapshotsImplemented
DescribeServerlessCachesImplemented
DescribeServiceUpdatesImplemented
DescribeSnapshotsImplemented
DescribeUpdateActionsImplemented
DescribeUserGroupsImplemented
DescribeUsersImplemented
DisassociateGlobalReplicationGroupImplemented
ExportServerlessCacheSnapshotImplemented
FailoverGlobalReplicationGroupImplemented
IncreaseNodeGroupsInGlobalReplicationGroupImplemented
IncreaseReplicaCountImplemented
ListAllowedNodeTypeModificationsImplemented
ListTagsForResourceImplemented
ModifyCacheClusterImplemented
ModifyCacheParameterGroupImplementedLocal observation: Vera 1.2.0 preview, 5 November 2026 — stored maxmemory-policy as allkeys-lru. Cache eviction wasn't checked.
ModifyCacheSubnetGroupImplemented
ModifyGlobalReplicationGroupImplemented
ModifyReplicationGroupImplemented
ModifyReplicationGroupShardConfigurationImplemented
ModifyServerlessCacheImplemented
ModifyUserImplemented
ModifyUserGroupImplemented
PurchaseReservedCacheNodesOfferingImplemented
RebalanceSlotsInGlobalReplicationGroupImplemented
RebootCacheClusterImplemented
RemoveTagsFromResourceImplemented
ResetCacheParameterGroupImplemented
RevokeCacheSecurityGroupIngressImplemented
StartMigrationImplemented
TestFailoverImplemented
TestMigrationImplemented