Accessing your cluster - Amazon MemoryDB for Redis
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Accessing your cluster

Your MemoryDB for Redis instances are designed to be accessed through an Amazon EC2 instance.

You can access your MemoryDB node from an Amazon EC2 instance in the same Amazon VPC. Or, by using VPC peering, you can access your MemoryDB node from an Amazon EC2 in a different Amazon VPC.

Grant access to your cluster

You can connect to your MemoryDB cluster only from an Amazon EC2 instance that is running in the same Amazon VPC. In this case, you will need to grant network ingress to the cluster.

To grant network ingress from an Amazon VPC security group to a cluster
  1. Sign in to the Amazon Web Services Management Console and open the Amazon EC2 console at

  2. In the left navigation pane, under Network & Security, choose Security Groups.

  3. From the list of security groups, choose the security group for your Amazon VPC. Unless you created a security group for MemoryDB use, this security group will be named default.

  4. Choose the Inbound tab, and then do the following:

    1. Choose Edit.

    2. Choose Add rule.

    3. In the Type column, choose Custom TCP rule.

    4. In the Port range box, type the port number for your cluster node. This number must be the same one that you specified when you launched the cluster. The default port for Redis is 6379.

    5. In the Source box, choose Anywhere which has the port range ( so that any Amazon EC2 instance that you launch within your Amazon VPC can connect to your MemoryDB nodes.


      Opening up the MemoryDB cluster to does not expose the cluster to the Internet because it has no public IP address and therefore cannot be accessed from outside the VPC. However, the default security group may be applied to other Amazon EC2 instances in the customer’s account, and those instances may have a public IP address. If they happen to be running something on the default port, then that service could be exposed unintentionally. Therefore, we recommend creating a VPC Security Group that will be used exclusively by MemoryDB. For more information, see Custom Security Groups.

    6. Choose Save.

When you launch an Amazon EC2 instance into your Amazon VPC, that instance will be able to connect to your MemoryDB cluster.

Accessing MemoryDB resources from outside Amazon

MemoryDB is a service designed to be used internally to your VPC. External access is discouraged due to the latency of Internet traffic and security concerns. However, if external access to MemoryDB is required for test or development purposes, it can be done through a VPN.

Using the Amazon Client VPN, you allow external access to your MemoryDB nodes with the following benefits:

  • Restricted access to approved users or authentication keys;

  • Encrypted traffic between the VPN Client and the Amazon VPN endpoint;

  • Limited access to specific subnets or nodes;

  • Easy revocation of access from users or authentication keys;

  • Audit connections;

The following procedures demonstrate how to:

Create a certificate authority

It is possible to create a Certificate Authority (CA) using different techniques or tools. We suggest the easy-rsa utility, provided by the OpenVPN project. Regardless of the option you choose, make sure to keep the keys secure. The following procedure downloads the easy-rsa scripts, creates the Certificate Authority and the keys to authenticate the first VPN client:

  • To create the initial certificates, open a terminal and do the following:

    • git clone

    • cd easy-rsa

    • ./easyrsa3/easyrsa init-pki

    • ./easyrsa3/easyrsa build-ca nopass

    • ./easyrsa3/easyrsa build-server-full server nopass

    • ./easyrsa3/easyrsa build-client-full client1.domain.tld nopass

    A pki subdirectory containing the certificates will be created under easy-rsa.

  • Submit the server certificate to the Amazon Certificate manager (ACM):

    • On the ACM console, select Certificate Manager.

    • Select Import Certificate.

    • Enter the public key certificate available in the easy-rsa/pki/issued/server.crt file in the Certificate body field.

    • Paste the private key available in the easy-rsa/pki/private/server.key in the Certificate private key field. Make sure to select all the lines between BEGIN AND END PRIVATE KEY (including the BEGIN and END lines).

    • Paste the CA public key available on the easy-rsa/pki/ca.crt file in the Certificate chain field.

    • Select Review and import.

    • Select Import.

    To submit the server's certificates to ACM using the Amazon CLI, run the following command: aws acm import-certificate --certificate fileb://easy-rsa/pki/issued/server.crt --private-key file://easy-rsa/pki/private/server.key --certificate-chain file://easy-rsa/pki/ca.crt --region region

    Note the Certificate ARN for future use.

Configuring Amazon client VPN components

Using the Amazon Console

On the Amazon console, select Services and then VPC.

Under Virtual Private Network, select Client VPN Endpoints and do the following:

Configuring Amazon Client VPN components

  • Select Create Client VPN Endpoint.

  • Specify the following options:

    • Client IPv4 CIDR: use a private network with a netmask of at least /22 range. Make sure that the selected subnet does not conflict with the VPC networks' addresses. Example:

    • In Server certificate ARN, select the ARN of the certificate previously imported.

    • Select Use mutual authentication.

    • In Client certificate ARN, select the ARN of the certificate previously imported.

    • Select Create Client VPN Endpoint.

Using the Amazon CLI

Run the following command:

aws ec2 create-client-vpn-endpoint --client-cidr-block "" --server-certificate-arn arn:aws:acm:us-east-1:012345678912:certificate/0123abcd-ab12-01a0-123a-123456abcdef --authentication-options Type=certificate-authentication,,MutualAuthentication={ClientRootCertificateChainArn=arn:aws:acm:us-east-1:012345678912:certificate/123abcd-ab12-01a0-123a-123456abcdef} --connection-log-options Enabled=false

Example output:

"ClientVpnEndpointId": "cvpn-endpoint-0123456789abcdefg", "Status": { "Code": "pending-associate" }, "DnsName": "" }

Associate the target networks to the VPN endpoint

  • Select the new VPN endpoint, and then select the Associations tab.

  • Select Associate and specify the following options.

    • VPC: Select the MemoryDB Cluster's VPC.

    • Select one of the MemoryDB cluster's networks. If in doubt, review the networks in the Subnet Groups on the MemoryDB dashboard.

    • Select Associate. If necessary, repeat the steps for the remaining networks.

Using the Amazon CLI

Run the following command:

aws ec2 associate-client-vpn-target-network --client-vpn-endpoint-id cvpn-endpoint-0123456789abcdefg --subnet-id subnet-0123456789abdcdef

Example output:

"Status": { "Code": "associating" }, "AssociationId": "cvpn-assoc-0123456789abdcdef" }

Review the VPN security group

The VPN Enpoint will automatically adopt the VPC's default security group. Check the inbound and outbound rules and confirm if the security group allows the traffic from the VPN network (defined on the VPN Endpoint settings) to the MemoryDB networks on the service ports (by default, 6379 for Redis).

If you need to change the security group assigned to the VPN Endpoint, proceed as follows:

  • Select the current security group.

  • Select Apply Security Group.

  • Select the new Security Group.

Using the Amazon CLI

Run the following command:

aws ec2 apply-security-groups-to-client-vpn-target-network --client-vpn-endpoint-id cvpn-endpoint-0123456789abcdefga  --vpc-id vpc-0123456789abdcdef --security-group-ids sg-0123456789abdcdef

Example output:

"SecurityGroupIds": [ "sg-0123456789abdcdef" ] }


The MemoryDB security group also needs to allow traffic coming from the VPN clients. The clients' addresses will be masked with the VPN Endpoint address, according to the VPC Network. Therefore, consider the VPC network (not the VPN Clients' network) when creating the inbound rule on the MemoryDB security group.

Authorize the VPN access to the destination networks

On the Authorization tab, select Authorize Ingress and specify the following:

  • Destination network to enable access: Either use to allow access to any network (including the Internet) or restrict the the MemoryDB networks/hosts.

  • Under Grant access to:, select Allow access to all users.

  • Select Add Authorization Rules.

Using the Amazon CLI

Run the following command:

aws ec2 authorize-client-vpn-ingress --client-vpn-endpoint-id cvpn-endpoint-0123456789abcdefg --target-network-cidr --authorize-all-groups

Example output:

{ "Status": { "Code": "authorizing" } }

Allowing access to the Internet from the VPN clients

If you need to browse the Internet through the VPN, you need to create an additional route. Select the Route Table tab and then select Create Route:

  • Route destination:

  • Target VPC Subnet ID: Select one of the associated subnets with access to the Internet.

  • Select Create Route.

Using the Amazon CLI

Run the following command:

aws ec2 create-client-vpn-route --client-vpn-endpoint-id cvpn-endpoint-0123456789abcdefg --destination-cidr-block --target-vpc-subnet-id subnet-0123456789abdcdef

Example output:

{ "Status": { "Code": "creating" } }

Configure the VPN client

On the Amazon Client VPN Dashboard, select the VPN endpoint recently created and select Download Client Configuration. Copy the configuration file, and the files easy-rsa/pki/issued/client1.domain.tld.crt and easy-rsa/pki/private/client1.domain.tld.key. Edit the configuration file and change or add the following parameters:

  • cert: add a new line with the parameter cert pointing to the client1.domain.tld.crt file. Use the full path to the file. Example: cert /home/user/.cert/client1.domain.tld.crt

  • cert: key: add a new line with the parameter key pointing to the client1.domain.tld.key file. Use the full path to the file. Example: key /home/user/.cert/client1.domain.tld.key

Establish the VPN connection with the command: sudo openvpn --config downloaded-client-config.ovpn

Revoking access

If you need to invalidate the access from a particular client key, the key needs to be revoked in the CA. Then submit the revocation list to Amazon Client VPN.

Revoking the key with easy-rsa:

  • cd easy-rsa

  • ./easyrsa3/easyrsa revoke client1.domain.tld

  • Enter "yes" to continue, or any other input to abort.

    Continue with revocation: `yes` ... * `./easyrsa3/easyrsa gen-crl

  • An updated CRL has been created. CRL file: /home/user/easy-rsa/pki/crl.pem

Importing the revocation list to the Amazon Client VPN:

  • On the Amazon Web Services Management Console, select Services and then VPC.

  • Select Client VPN Endpoints.

  • Select the Client VPN Endpoint and then select Actions -> Import Client Certificate CRL.

  • Paste the contents of the crl.pem file.

Using the Amazon CLI

Run the following command:

aws ec2 import-client-vpn-client-certificate-revocation-list --certificate-revocation-list file://./easy-rsa/pki/crl.pem --client-vpn-endpoint-id cvpn-endpoint-0123456789abcdefg

Example output:

Example output: { "Return": true }