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Guides

Memcached

This guide shows you how to use Memcached. Memcached is an in-memory key-value store for small chunks of arbitrary data (strings, objects) from results of database calls, API calls, or page rendering.

To run it, follow these steps:

1. Install the CLI and a container runtime engine, for example Docker. Use the unikraft CLI or the legacy kraft CLI.

2. Clone the examples repository and cd into the examples/memcached1.6/ directory:

Code
git clone https://github.com/unikraft-cloud/examples
cd examples/memcached1.6/

Make sure to log into Unikraft Cloud and pick a metro close to you. This guide uses fra (Frankfurt, 🇩🇪):

When done, invoke the following command to deploy this app on Unikraft Cloud:

The output shows the instance address and other details:

Code
[●] Deployed successfully!
 │
 ├────────── name: memcached16-arkv7
 ├────────── uuid: da436eca-bc64-46d7-a04c-72832652b10e
 ├───────── state: running
 ├────────── fqdn: weathered-smoke-hehsdinv.fra.unikraft.app
 ├───────── image: memcached16@sha256:f53cdbce4dc185e8acc8ecb93a0ab0ba99085ca0837a0ad2062aae9e31382e58
 ├───── boot time: 19.27 ms
 ├──────── memory: 256 MiB
 ├─────── service: weathered-smoke-hehsdinv
 ├── private fqdn: memcached16-arkv7.internal
 ├──── private ip: 172.16.6.5
 └────────── args: /usr/bin/memcached -u root

In this case, the instance name is memcached16-arkv7 which is different for each run.

To test the deployment, first forward the port with the kraft cloud tunnel command:

Code
kraft cloud tunnel 11211:memcached16-arkv7:11211

The kraft cloud tunnel command is only supported by the legacy CLI.

Now, on a separate console, run the following commands to test that it works (you should see output when incrementing):

Code
telnet 127.0.0.1 11211
set test 0 0 1
0
incr test 1
incr test 1

To exit telnet run:

Code
Ctrl + ]
Ctrl + C

To disconnect, kill the tunnel command with ctrl-C.

Note: This guide uses kraft cloud tunnel only when a service doesn't support TLS and isn't HTTP-based (TLS/SNI determines the correct instance to send traffic to). Also note that the tunnel command isn't needed when connecting via an instance's private IP/FQDN. For example when a Memcached instance serves as a cache server to another instance that acts as a frontend and which does support TLS.

You can list information about the instance by running:

Code
NAME               FQDN                                       STATE    STATUS          IMAGE                            MEMORY   VCPUS  ARGS                        BOOT TIME
memcached16-arkv7  weathered-smoke-hehsdinv.fra.unikraft.app  running  11 minutes ago  memcached16@sha256:f53cdbce4...  256 MiB  1      /usr/bin/memcached -u root  19266us

When done, you can remove the instance:

Customize your app

To customize the app, update the files in the repository, listed below:

• Kraftfile: the Unikraft Cloud specification, including command-line arguments
• Dockerfile: In case you need to add files to your instance's rootfs

Learn more

Use the --help option for detailed information on using Unikraft Cloud:

Or visit the CLI Reference or the legacy CLI Reference.