Connect to a Memcached instance

This page explains how to connect to a Memorystore for Memcached instance. You can connect to Memcached instances from Compute Engine VM instances, Google Kubernetes Engine clusters, Cloud Run functions, the App Engine flexible environment, and the App Engine standard environment.

Before you can access Memorystore with Cloud Run functions, you need follow the setup instructions at Connecting to internal resources in a VPC network.

Also, before you can access Memorystore with the App Engine standard environment, you need to follow the setup instructions at Connecting to internal resources in a VPC network.

Note: You can use any open source Memcached client library to connect to Memorystore for Memcached.

Connecting to a Memcached instance from a Compute Engine VM

In order to connect to a Memcached instance, a Compute Engine VM instance must be located within the same project and region, and must also be connected to the same network or VPC network as the Memcached instance.

1. Connect to a Linux VM. For steps to connect to a Linux VM, see Quickstart Using a Linux VM. If you used a Debian based image to create your VM instance as described in the quickstart, install telnet using apt-get:

   sudo apt-get install telnet
   

2. From the terminal, telnet to the IP address of one of the Memcached nodes, replacing variables with appropriate values.

   telnet node-ip-address 11211
   

   If it works correctly, you should see the following output with the [bracketed-variables] replaced by your project's variables:

   Trying [node-ip-address]
   Connected to [node-ip-address]
   

3. In the telnet session, enter some Memcached commands:

   Enter:

   get greeting
   

   Result:

   END
   

   Enter:

   set greeting 1 0 11
   hello world
   

   Result:

   STORED
   

   Enter:

   get greeting
   

   Result:

   VALUE greeting 1 11
   hello world
   END
   

Memorystore for Memcached supports standard open source Memcached libraries.

Connecting to a Memcached instance from a Google Kubernetes Engine cluster

Note: You cannot connect to a Memorystore for Memcached instance from a Google Kubernetes Engine cluster without VPC-native/IP aliasing enabled. To verify if your instance has VPC-native/IP aliasing enabled, check your cluster's details page in the Google Cloud console. Alternatively, run gcloud container clusters describe and verify if useIpAliases: true is present.

It is easiest to enable VPC-native/IP aliasing during cluster creation. When creating your cluster, select VPC Native under advanced options. For more details, see Creating VPC-native clusters using Alias IPs.

You can connect to your Memcached instances using GKE clusters that are in the same region and connected to the same network as your instance.

1. Go to the Google Kubernetes Engine page in the Google Cloud console.
   Google Kubernetes Engine

2. Click on the GKE cluster you'd like to connect from. If you don't already have a cluster, create one in the same zone and region as your Memcached instance with IP aliases enabled. For instructions on how to create a cluster with IP aliases enabled, see the Creating a VPC-native cluster.

3. Click the Connect button to the right of your cluster's name, then click the Run in Cloud Shell button in the window that appears.

4. Configure kubectl command line access by running the following command:

   gcloud container clusters get-credentials cluster-name --zone=cluster-zone --project=project-id
   

   • cluster-name is the name of your cluster.

   • cluster-zone is the zone your cluster is in. This must also be the zone your Memcached instance is in.

   • project-id is the project in which your cluster and your Memcached instance are located.

   If the command is successful, you should receive the following message:

   kubeconfig generated for cluster-name
   

   If you do not receive this message, make sure you entered the correct cluster information into the command.

5. If your cluster is version 1.8 or higher and has IP aliases enabled, skip this step. If your cluster is version 1.7 or lower, or your version 1.8 or higher cluster doesn't have IP aliases enabled, follow these workaround steps before trying to connect to your instance:

   Workaround

   Run these three commands, replacing reserved-ip-range with the reserved IP range of your instance:

   git clone https://github.com/bowei/k8s-custom-iptables.git
   

   cd k8s-custom-iptables/
   

   TARGETS="reserved-ip-range" ./install.sh
   

   Note: If you don't know the reserved IP range of your instance, you can find out by running the following command:

   gcloud memcache instances describe instance-id --region=region
   

   For more information about IP aliases, including how to create a cluster with this setting enabled, see Creating a VPC-native cluster.

6. Use the following command to connect to a bash shell:

   kubectl run -i --tty busybox --image=busybox -- sh
   

7. Telnet to your Memcached instance using one of your node's IP addresses and your instance's port number:

   telnet node-ip-address 11211
   

8. In the telnet session, enter some Memcached commands:

   Enter:

   get greeting
   

   Result:

   END
   

   Enter:

   set greeting 1 0 11
   hello world
   

   Result:

   STORED
   

   Enter:

   get greeting
   

   Result:

   VALUE greeting 1 11
   hello world
   END
   

Memorystore for Memcached supports standard open source Memcached libraries.

What's next

• Use the Auto Discovery service.
• Monitor your Memcached instances.